mySQL 5.0.11 sources for tomato

[tomato.git] / release / src / router / mysql / storage / innodb_plugin / ibuf / ibuf0ibuf.c

/*****************************************************************************

Copyright (c) 1997, 2013, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file ibuf/ibuf0ibuf.c
Insert buffer

Created 7/19/1997 Heikki Tuuri
*******************************************************/

#include "ibuf0ibuf.h"

/** Number of bits describing a single page */
#define IBUF_BITS_PER_PAGE      4
#if IBUF_BITS_PER_PAGE % 2
# error "IBUF_BITS_PER_PAGE must be an even number!"
#endif
/** The start address for an insert buffer bitmap page bitmap */
#define IBUF_BITMAP             PAGE_DATA

#ifdef UNIV_NONINL
#include "ibuf0ibuf.ic"
#endif

#ifndef UNIV_HOTBACKUP

#include "buf0buf.h"
#include "buf0rea.h"
#include "fsp0fsp.h"
#include "trx0sys.h"
#include "fil0fil.h"
#include "thr0loc.h"
#include "rem0rec.h"
#include "btr0cur.h"
#include "btr0pcur.h"
#include "btr0btr.h"
#include "row0upd.h"
#include "sync0sync.h"
#include "dict0boot.h"
#include "fut0lst.h"
#include "lock0lock.h"
#include "log0recv.h"
#include "que0que.h"
#include "rem0cmp.h"

/*      STRUCTURE OF AN INSERT BUFFER RECORD

In versions < 4.1.x:

1. The first field is the page number.
2. The second field is an array which stores type info for each subsequent
   field. We store the information which affects the ordering of records, and
   also the physical storage size of an SQL NULL value. E.g., for CHAR(10) it
   is 10 bytes.
3. Next we have the fields of the actual index record.

In versions >= 4.1.x:

Note that contary to what we planned in the 1990's, there will only be one
insert buffer tree, and that is in the system tablespace of InnoDB.

1. The first field is the space id.
2. The second field is a one-byte marker (0) which differentiates records from
   the < 4.1.x storage format.
3. The third field is the page number.
4. The fourth field contains the type info, where we have also added 2 bytes to
   store the charset. In the compressed table format of 5.0.x we must add more
   information here so that we can build a dummy 'index' struct which 5.0.x
   can use in the binary search on the index page in the ibuf merge phase.
5. The rest of the fields contain the fields of the actual index record.

In versions >= 5.0.3:

The first byte of the fourth field is an additional marker (0) if the record
is in the compact format.  The presence of this marker can be detected by
looking at the length of the field modulo DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE.

The high-order bit of the character set field in the type info is the
"nullable" flag for the field. */


/*      PREVENTING DEADLOCKS IN THE INSERT BUFFER SYSTEM

If an OS thread performs any operation that brings in disk pages from
non-system tablespaces into the buffer pool, or creates such a page there,
then the operation may have as a side effect an insert buffer index tree
compression. Thus, the tree latch of the insert buffer tree may be acquired
in the x-mode, and also the file space latch of the system tablespace may
be acquired in the x-mode.

Also, an insert to an index in a non-system tablespace can have the same
effect. How do we know this cannot lead to a deadlock of OS threads? There
is a problem with the i\o-handler threads: they break the latching order
because they own x-latches to pages which are on a lower level than the
insert buffer tree latch, its page latches, and the tablespace latch an
insert buffer operation can reserve.

The solution is the following: Let all the tree and page latches connected
with the insert buffer be later in the latching order than the fsp latch and
fsp page latches.

Insert buffer pages must be such that the insert buffer is never invoked
when these pages are accessed as this would result in a recursion violating
the latching order. We let a special i/o-handler thread take care of i/o to
the insert buffer pages and the ibuf bitmap pages, as well as the fsp bitmap
pages and the first inode page, which contains the inode of the ibuf tree: let
us call all these ibuf pages. To prevent deadlocks, we do not let a read-ahead
access both non-ibuf and ibuf pages.

Then an i/o-handler for the insert buffer never needs to access recursively the
insert buffer tree and thus obeys the latching order. On the other hand, other
i/o-handlers for other tablespaces may require access to the insert buffer,
but because all kinds of latches they need to access there are later in the
latching order, no violation of the latching order occurs in this case,
either.

A problem is how to grow and contract an insert buffer tree. As it is later
in the latching order than the fsp management, we have to reserve the fsp
latch first, before adding or removing pages from the insert buffer tree.
We let the insert buffer tree have its own file space management: a free
list of pages linked to the tree root. To prevent recursive using of the
insert buffer when adding pages to the tree, we must first load these pages
to memory, obtaining a latch on them, and only after that add them to the
free list of the insert buffer tree. More difficult is removing of pages
from the free list. If there is an excess of pages in the free list of the
ibuf tree, they might be needed if some thread reserves the fsp latch,
intending to allocate more file space. So we do the following: if a thread
reserves the fsp latch, we check the writer count field of the latch. If
this field has value 1, it means that the thread did not own the latch
before entering the fsp system, and the mtr of the thread contains no
modifications to the fsp pages. Now we are free to reserve the ibuf latch,
and check if there is an excess of pages in the free list. We can then, in a
separate mini-transaction, take them out of the free list and free them to
the fsp system.

To avoid deadlocks in the ibuf system, we divide file pages into three levels:

(1) non-ibuf pages,
(2) ibuf tree pages and the pages in the ibuf tree free list, and
(3) ibuf bitmap pages.

No OS thread is allowed to access higher level pages if it has latches to
lower level pages; even if the thread owns a B-tree latch it must not access
the B-tree non-leaf pages if it has latches on lower level pages. Read-ahead
is only allowed for level 1 and 2 pages. Dedicated i/o-handler threads handle
exclusively level 1 i/o. A dedicated i/o handler thread handles exclusively
level 2 i/o. However, if an OS thread does the i/o handling for itself, i.e.,
it uses synchronous aio, it can access any pages, as long as it obeys the
access order rules. */

/** Buffer pool size per the maximum insert buffer size */
#define IBUF_POOL_SIZE_PER_MAX_SIZE     2

/** Table name for the insert buffer. */
#define IBUF_TABLE_NAME         "SYS_IBUF_TABLE"

/** Operations that can currently be buffered. */
UNIV_INTERN ibuf_use_t  ibuf_use                = IBUF_USE_INSERT;

#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
/** Flag to control insert buffer debugging. */
UNIV_INTERN uint        ibuf_debug;
#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */

/** The insert buffer control structure */
UNIV_INTERN ibuf_t*     ibuf                    = NULL;

/** Counter for ibuf_should_try() */
UNIV_INTERN ulint       ibuf_flush_count        = 0;

#ifdef UNIV_IBUF_COUNT_DEBUG
/** Number of tablespaces in the ibuf_counts array */
#define IBUF_COUNT_N_SPACES     4
/** Number of pages within each tablespace in the ibuf_counts array */
#define IBUF_COUNT_N_PAGES      130000

/** Buffered entry counts for file pages, used in debugging */
static ulint    ibuf_counts[IBUF_COUNT_N_SPACES][IBUF_COUNT_N_PAGES];

/******************************************************************//**
Checks that the indexes to ibuf_counts[][] are within limits. */
UNIV_INLINE
void
ibuf_count_check(
/*=============*/
        ulint   space_id,       /*!< in: space identifier */
        ulint   page_no)        /*!< in: page number */
{
        if (space_id < IBUF_COUNT_N_SPACES && page_no < IBUF_COUNT_N_PAGES) {
                return;
        }

        fprintf(stderr,
                "InnoDB: UNIV_IBUF_COUNT_DEBUG limits space_id and page_no\n"
                "InnoDB: and breaks crash recovery.\n"
                "InnoDB: space_id=%lu, should be 0<=space_id<%lu\n"
                "InnoDB: page_no=%lu, should be 0<=page_no<%lu\n",
                (ulint) space_id, (ulint) IBUF_COUNT_N_SPACES,
                (ulint) page_no, (ulint) IBUF_COUNT_N_PAGES);
        ut_error;
}
#endif

/** @name Offsets to the per-page bits in the insert buffer bitmap */
/* @{ */
#define IBUF_BITMAP_FREE        0       /*!< Bits indicating the
                                        amount of free space */
#define IBUF_BITMAP_BUFFERED    2       /*!< TRUE if there are buffered
                                        changes for the page */
#define IBUF_BITMAP_IBUF        3       /*!< TRUE if page is a part of
                                        the ibuf tree, excluding the
                                        root page, or is in the free
                                        list of the ibuf */
/* @} */

/** The mutex used to block pessimistic inserts to ibuf trees */
static mutex_t  ibuf_pessimistic_insert_mutex;

/** The mutex protecting the insert buffer structs */
static mutex_t  ibuf_mutex;

/** The mutex protecting the insert buffer bitmaps */
static mutex_t  ibuf_bitmap_mutex;

/** The area in pages from which contract looks for page numbers for merge */
#define IBUF_MERGE_AREA                 8

/** Inside the merge area, pages which have at most 1 per this number less
buffered entries compared to maximum volume that can buffered for a single
page are merged along with the page whose buffer became full */
#define IBUF_MERGE_THRESHOLD            4

/** In ibuf_contract at most this number of pages is read to memory in one
batch, in order to merge the entries for them in the insert buffer */
#define IBUF_MAX_N_PAGES_MERGED         IBUF_MERGE_AREA

/** If the combined size of the ibuf trees exceeds ibuf->max_size by this
many pages, we start to contract it in connection to inserts there, using
non-synchronous contract */
#define IBUF_CONTRACT_ON_INSERT_NON_SYNC        0

/** If the combined size of the ibuf trees exceeds ibuf->max_size by this
many pages, we start to contract it in connection to inserts there, using
synchronous contract */
#define IBUF_CONTRACT_ON_INSERT_SYNC            5

/** If the combined size of the ibuf trees exceeds ibuf->max_size by
this many pages, we start to contract it synchronous contract, but do
not insert */
#define IBUF_CONTRACT_DO_NOT_INSERT             10

/* TODO: how to cope with drop table if there are records in the insert
buffer for the indexes of the table? Is there actually any problem,
because ibuf merge is done to a page when it is read in, and it is
still physically like the index page even if the index would have been
dropped! So, there seems to be no problem. */

/******************************************************************//**
Sets the flag in the current OS thread local storage denoting that it is
inside an insert buffer routine. */
UNIV_INLINE
void
ibuf_enter(void)
/*============*/
{
        ibool*  ptr;

        ptr = thr_local_get_in_ibuf_field();

        ut_ad(*ptr == FALSE);

        *ptr = TRUE;
}

/******************************************************************//**
Sets the flag in the current OS thread local storage denoting that it is
exiting an insert buffer routine. */
UNIV_INLINE
void
ibuf_exit(void)
/*===========*/
{
        ibool*  ptr;

        ptr = thr_local_get_in_ibuf_field();

        ut_ad(*ptr == TRUE);

        *ptr = FALSE;
}

/******************************************************************//**
Returns TRUE if the current OS thread is performing an insert buffer
routine.

For instance, a read-ahead of non-ibuf pages is forbidden by threads
that are executing an insert buffer routine.
@return TRUE if inside an insert buffer routine */
UNIV_INTERN
ibool
ibuf_inside(void)
/*=============*/
{
        return(*thr_local_get_in_ibuf_field());
}

/******************************************************************//**
Gets the ibuf header page and x-latches it.
@return insert buffer header page */
static
page_t*
ibuf_header_page_get(
/*=================*/
        mtr_t*  mtr)    /*!< in: mtr */
{
        buf_block_t*    block;

        ut_ad(!ibuf_inside());

        block = buf_page_get(
                IBUF_SPACE_ID, 0, FSP_IBUF_HEADER_PAGE_NO, RW_X_LATCH, mtr);
        buf_block_dbg_add_level(block, SYNC_IBUF_HEADER);

        return(buf_block_get_frame(block));
}

/******************************************************************//**
Gets the root page and x-latches it.
@return insert buffer tree root page */
static
page_t*
ibuf_tree_root_get(
/*===============*/
        mtr_t*          mtr)    /*!< in: mtr */
{
        buf_block_t*    block;

        ut_ad(ibuf_inside());

        mtr_x_lock(dict_index_get_lock(ibuf->index), mtr);

        block = buf_page_get(
                IBUF_SPACE_ID, 0, FSP_IBUF_TREE_ROOT_PAGE_NO, RW_X_LATCH, mtr);

        buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);

        return(buf_block_get_frame(block));
}

#ifdef UNIV_IBUF_COUNT_DEBUG
/******************************************************************//**
Gets the ibuf count for a given page.
@return number of entries in the insert buffer currently buffered for
this page */
UNIV_INTERN
ulint
ibuf_count_get(
/*===========*/
        ulint   space,  /*!< in: space id */
        ulint   page_no)/*!< in: page number */
{
        ibuf_count_check(space, page_no);

        return(ibuf_counts[space][page_no]);
}

/******************************************************************//**
Sets the ibuf count for a given page. */
static
void
ibuf_count_set(
/*===========*/
        ulint   space,  /*!< in: space id */
        ulint   page_no,/*!< in: page number */
        ulint   val)    /*!< in: value to set */
{
        ibuf_count_check(space, page_no);
        ut_a(val < UNIV_PAGE_SIZE);

        ibuf_counts[space][page_no] = val;
}
#endif

/******************************************************************//**
Closes insert buffer and frees the data structures. */
UNIV_INTERN
void
ibuf_close(void)
/*============*/
{
        mutex_free(&ibuf_pessimistic_insert_mutex);
        memset(&ibuf_pessimistic_insert_mutex,
               0x0, sizeof(ibuf_pessimistic_insert_mutex));

        mutex_free(&ibuf_mutex);
        memset(&ibuf_mutex, 0x0, sizeof(ibuf_mutex));

        mutex_free(&ibuf_bitmap_mutex);
        memset(&ibuf_bitmap_mutex, 0x0, sizeof(ibuf_mutex));

        mem_free(ibuf);
        ibuf = NULL;
}

/******************************************************************//**
Updates the size information of the ibuf, assuming the segment size has not
changed. */
static
void
ibuf_size_update(
/*=============*/
        const page_t*   root,   /*!< in: ibuf tree root */
        mtr_t*          mtr)    /*!< in: mtr */
{
        ut_ad(mutex_own(&ibuf_mutex));

        ibuf->free_list_len = flst_get_len(root + PAGE_HEADER
                                           + PAGE_BTR_IBUF_FREE_LIST, mtr);

        ibuf->height = 1 + btr_page_get_level(root, mtr);

        /* the '1 +' is the ibuf header page */
        ibuf->size = ibuf->seg_size - (1 + ibuf->free_list_len);

        ibuf->empty = page_get_n_recs(root) == 0;
}

/******************************************************************//**
Creates the insert buffer data structure at a database startup and initializes
the data structures for the insert buffer. */
UNIV_INTERN
void
ibuf_init_at_db_start(void)
/*=======================*/
{
        page_t*         root;
        mtr_t           mtr;
        dict_table_t*   table;
        mem_heap_t*     heap;
        dict_index_t*   index;
        ulint           n_used;
        page_t*         header_page;
        ulint           error;

        ibuf = mem_alloc(sizeof(ibuf_t));

        memset(ibuf, 0, sizeof(*ibuf));

        /* Note that also a pessimistic delete can sometimes make a B-tree
        grow in size, as the references on the upper levels of the tree can
        change */

        ibuf->max_size = buf_pool_get_curr_size() / UNIV_PAGE_SIZE
                / IBUF_POOL_SIZE_PER_MAX_SIZE;

        mutex_create(&ibuf_pessimistic_insert_mutex,
                     SYNC_IBUF_PESS_INSERT_MUTEX);

        mutex_create(&ibuf_mutex, SYNC_IBUF_MUTEX);

        mutex_create(&ibuf_bitmap_mutex, SYNC_IBUF_BITMAP_MUTEX);

        mtr_start(&mtr);

        mutex_enter(&ibuf_mutex);

        mtr_x_lock(fil_space_get_latch(IBUF_SPACE_ID, NULL), &mtr);

        header_page = ibuf_header_page_get(&mtr);

        fseg_n_reserved_pages(header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER,
                              &n_used, &mtr);
        ibuf_enter();

        ut_ad(n_used >= 2);

        ibuf->seg_size = n_used;

        {
                buf_block_t*    block;

                block = buf_page_get(
                        IBUF_SPACE_ID, 0, FSP_IBUF_TREE_ROOT_PAGE_NO,
                        RW_X_LATCH, &mtr);
                buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);

                root = buf_block_get_frame(block);
        }

        ibuf_size_update(root, &mtr);
        mutex_exit(&ibuf_mutex);

        mtr_commit(&mtr);

        ibuf_exit();

        heap = mem_heap_create(450);

        /* Use old-style record format for the insert buffer. */
        table = dict_mem_table_create(IBUF_TABLE_NAME, IBUF_SPACE_ID, 1, 0);

        dict_mem_table_add_col(table, heap, "DUMMY_COLUMN", DATA_BINARY, 0, 0);

        table->id = ut_dulint_add(DICT_IBUF_ID_MIN, IBUF_SPACE_ID);

        dict_table_add_to_cache(table, heap);
        mem_heap_free(heap);

        index = dict_mem_index_create(
                IBUF_TABLE_NAME, "CLUST_IND",
                IBUF_SPACE_ID, DICT_CLUSTERED | DICT_UNIVERSAL | DICT_IBUF, 1);

        dict_mem_index_add_field(index, "DUMMY_COLUMN", 0);

        index->id = ut_dulint_add(DICT_IBUF_ID_MIN, IBUF_SPACE_ID);

        error = dict_index_add_to_cache(table, index,
                                        FSP_IBUF_TREE_ROOT_PAGE_NO, FALSE);
        ut_a(error == DB_SUCCESS);

        ibuf->index = dict_table_get_first_index(table);
}
#endif /* !UNIV_HOTBACKUP */
/*********************************************************************//**
Initializes an ibuf bitmap page. */
UNIV_INTERN
void
ibuf_bitmap_page_init(
/*==================*/
        buf_block_t*    block,  /*!< in: bitmap page */
        mtr_t*          mtr)    /*!< in: mtr */
{
        page_t* page;
        ulint   byte_offset;
        ulint   zip_size = buf_block_get_zip_size(block);

        ut_a(ut_is_2pow(zip_size));

        page = buf_block_get_frame(block);
        fil_page_set_type(page, FIL_PAGE_IBUF_BITMAP);

        /* Write all zeros to the bitmap */

        if (!zip_size) {
                byte_offset = UT_BITS_IN_BYTES(UNIV_PAGE_SIZE
                                               * IBUF_BITS_PER_PAGE);
        } else {
                byte_offset = UT_BITS_IN_BYTES(zip_size * IBUF_BITS_PER_PAGE);
        }

        memset(page + IBUF_BITMAP, 0, byte_offset);

        /* The remaining area (up to the page trailer) is uninitialized. */

#ifndef UNIV_HOTBACKUP
        mlog_write_initial_log_record(page, MLOG_IBUF_BITMAP_INIT, mtr);
#endif /* !UNIV_HOTBACKUP */
}

/*********************************************************************//**
Parses a redo log record of an ibuf bitmap page init.
@return end of log record or NULL */
UNIV_INTERN
byte*
ibuf_parse_bitmap_init(
/*===================*/
        byte*           ptr,    /*!< in: buffer */
        byte*           end_ptr __attribute__((unused)), /*!< in: buffer end */
        buf_block_t*    block,  /*!< in: block or NULL */
        mtr_t*          mtr)    /*!< in: mtr or NULL */
{
        ut_ad(ptr && end_ptr);

        if (block) {
                ibuf_bitmap_page_init(block, mtr);
        }

        return(ptr);
}
#ifndef UNIV_HOTBACKUP
/********************************************************************//**
Gets the desired bits for a given page from a bitmap page.
@return value of bits */
UNIV_INLINE
ulint
ibuf_bitmap_page_get_bits(
/*======================*/
        const page_t*   page,   /*!< in: bitmap page */
        ulint           page_no,/*!< in: page whose bits to get */
        ulint           zip_size,/*!< in: compressed page size in bytes;
                                0 for uncompressed pages */
        ulint           bit,    /*!< in: IBUF_BITMAP_FREE,
                                IBUF_BITMAP_BUFFERED, ... */
        mtr_t*          mtr __attribute__((unused)))
                                /*!< in: mtr containing an
                                x-latch to the bitmap page */
{
        ulint   byte_offset;
        ulint   bit_offset;
        ulint   map_byte;
        ulint   value;

        ut_ad(bit < IBUF_BITS_PER_PAGE);
#if IBUF_BITS_PER_PAGE % 2
# error "IBUF_BITS_PER_PAGE % 2 != 0"
#endif
        ut_ad(ut_is_2pow(zip_size));
        ut_ad(mtr_memo_contains_page(mtr, page, MTR_MEMO_PAGE_X_FIX));

        if (!zip_size) {
                bit_offset = (page_no % UNIV_PAGE_SIZE) * IBUF_BITS_PER_PAGE
                        + bit;
        } else {
                bit_offset = (page_no & (zip_size - 1)) * IBUF_BITS_PER_PAGE
                        + bit;
        }

        byte_offset = bit_offset / 8;
        bit_offset = bit_offset % 8;

        ut_ad(byte_offset + IBUF_BITMAP < UNIV_PAGE_SIZE);

        map_byte = mach_read_from_1(page + IBUF_BITMAP + byte_offset);

        value = ut_bit_get_nth(map_byte, bit_offset);

        if (bit == IBUF_BITMAP_FREE) {
                ut_ad(bit_offset + 1 < 8);

                value = value * 2 + ut_bit_get_nth(map_byte, bit_offset + 1);
        }

        return(value);
}

/********************************************************************//**
Sets the desired bit for a given page in a bitmap page. */
static
void
ibuf_bitmap_page_set_bits(
/*======================*/
        page_t* page,   /*!< in: bitmap page */
        ulint   page_no,/*!< in: page whose bits to set */
        ulint   zip_size,/*!< in: compressed page size in bytes;
                        0 for uncompressed pages */
        ulint   bit,    /*!< in: IBUF_BITMAP_FREE, IBUF_BITMAP_BUFFERED, ... */
        ulint   val,    /*!< in: value to set */
        mtr_t*  mtr)    /*!< in: mtr containing an x-latch to the bitmap page */
{
        ulint   byte_offset;
        ulint   bit_offset;
        ulint   map_byte;

        ut_ad(bit < IBUF_BITS_PER_PAGE);
#if IBUF_BITS_PER_PAGE % 2
# error "IBUF_BITS_PER_PAGE % 2 != 0"
#endif
        ut_ad(ut_is_2pow(zip_size));
        ut_ad(mtr_memo_contains_page(mtr, page, MTR_MEMO_PAGE_X_FIX));
#ifdef UNIV_IBUF_COUNT_DEBUG
        ut_a((bit != IBUF_BITMAP_BUFFERED) || (val != FALSE)
             || (0 == ibuf_count_get(page_get_space_id(page),
                                     page_no)));
#endif
        if (!zip_size) {
                bit_offset = (page_no % UNIV_PAGE_SIZE) * IBUF_BITS_PER_PAGE
                        + bit;
        } else {
                bit_offset = (page_no & (zip_size - 1)) * IBUF_BITS_PER_PAGE
                        + bit;
        }

        byte_offset = bit_offset / 8;
        bit_offset = bit_offset % 8;

        ut_ad(byte_offset + IBUF_BITMAP < UNIV_PAGE_SIZE);

        map_byte = mach_read_from_1(page + IBUF_BITMAP + byte_offset);

        if (bit == IBUF_BITMAP_FREE) {
                ut_ad(bit_offset + 1 < 8);
                ut_ad(val <= 3);

                map_byte = ut_bit_set_nth(map_byte, bit_offset, val / 2);
                map_byte = ut_bit_set_nth(map_byte, bit_offset + 1, val % 2);
        } else {
                ut_ad(val <= 1);
                map_byte = ut_bit_set_nth(map_byte, bit_offset, val);
        }

        mlog_write_ulint(page + IBUF_BITMAP + byte_offset, map_byte,
                         MLOG_1BYTE, mtr);
}

/********************************************************************//**
Calculates the bitmap page number for a given page number.
@return the bitmap page number where the file page is mapped */
UNIV_INLINE
ulint
ibuf_bitmap_page_no_calc(
/*=====================*/
        ulint   zip_size,       /*!< in: compressed page size in bytes;
                                0 for uncompressed pages */
        ulint   page_no)        /*!< in: tablespace page number */
{
        ut_ad(ut_is_2pow(zip_size));

        if (!zip_size) {
                return(FSP_IBUF_BITMAP_OFFSET
                       + (page_no & ~(UNIV_PAGE_SIZE - 1)));
        } else {
                return(FSP_IBUF_BITMAP_OFFSET
                       + (page_no & ~(zip_size - 1)));
        }
}

/********************************************************************//**
Gets the ibuf bitmap page where the bits describing a given file page are
stored.
@return bitmap page where the file page is mapped, that is, the bitmap
page containing the descriptor bits for the file page; the bitmap page
is x-latched */
static
page_t*
ibuf_bitmap_get_map_page_func(
/*==========================*/
        ulint           space,  /*!< in: space id of the file page */
        ulint           page_no,/*!< in: page number of the file page */
        ulint           zip_size,/*!< in: compressed page size in bytes;
                                0 for uncompressed pages */
        const char*     file,   /*!< in: file name */
        ulint           line,   /*!< in: line where called */
        mtr_t*          mtr)    /*!< in: mtr */
{
        buf_block_t*    block;

        block = buf_page_get_gen(space, zip_size,
                                 ibuf_bitmap_page_no_calc(zip_size, page_no),
                                 RW_X_LATCH, NULL, BUF_GET,
                                 file, line, mtr);
        buf_block_dbg_add_level(block, SYNC_IBUF_BITMAP);

        return(buf_block_get_frame(block));
}

/********************************************************************//**
Gets the ibuf bitmap page where the bits describing a given file page are
stored.
@return bitmap page where the file page is mapped, that is, the bitmap
page containing the descriptor bits for the file page; the bitmap page
is x-latched
@param space    in: space id of the file page
@param page_no  in: page number of the file page
@param zip_size in: compressed page size in bytes; 0 for uncompressed pages
@param mtr      in: mini-transaction */
#define ibuf_bitmap_get_map_page(space, page_no, zip_size, mtr)         \
        ibuf_bitmap_get_map_page_func(space, page_no, zip_size,         \
                                      __FILE__, __LINE__, mtr)

/************************************************************************//**
Sets the free bits of the page in the ibuf bitmap. This is done in a separate
mini-transaction, hence this operation does not restrict further work to only
ibuf bitmap operations, which would result if the latch to the bitmap page
were kept. */
UNIV_INLINE
void
ibuf_set_free_bits_low(
/*===================*/
        ulint                   zip_size,/*!< in: compressed page size in bytes;
                                        0 for uncompressed pages */
        const buf_block_t*      block,  /*!< in: index page; free bits are set if
                                        the index is non-clustered and page
                                        level is 0 */
        ulint                   val,    /*!< in: value to set: < 4 */
        mtr_t*                  mtr)    /*!< in/out: mtr */
{
        page_t* bitmap_page;
        ulint   space;
        ulint   page_no;

        if (!page_is_leaf(buf_block_get_frame(block))) {

                return;
        }

        space = buf_block_get_space(block);
        page_no = buf_block_get_page_no(block);
        bitmap_page = ibuf_bitmap_get_map_page(space, page_no, zip_size, mtr);
#ifdef UNIV_IBUF_DEBUG
# if 0
        fprintf(stderr,
                "Setting space %lu page %lu free bits to %lu should be %lu\n",
                space, page_no, val,
                ibuf_index_page_calc_free(zip_size, block));
# endif

        ut_a(val <= ibuf_index_page_calc_free(zip_size, block));
#endif /* UNIV_IBUF_DEBUG */
        ibuf_bitmap_page_set_bits(bitmap_page, page_no, zip_size,
                                  IBUF_BITMAP_FREE, val, mtr);
}

/************************************************************************//**
Sets the free bit of the page in the ibuf bitmap. This is done in a separate
mini-transaction, hence this operation does not restrict further work to only
ibuf bitmap operations, which would result if the latch to the bitmap page
were kept. */
UNIV_INTERN
void
ibuf_set_free_bits_func(
/*====================*/
        buf_block_t*    block,  /*!< in: index page of a non-clustered index;
                                free bit is reset if page level is 0 */
#ifdef UNIV_IBUF_DEBUG
        ulint           max_val,/*!< in: ULINT_UNDEFINED or a maximum
                                value which the bits must have before
                                setting; this is for debugging */
#endif /* UNIV_IBUF_DEBUG */
        ulint           val)    /*!< in: value to set: < 4 */
{
        mtr_t   mtr;
        page_t* page;
        page_t* bitmap_page;
        ulint   space;
        ulint   page_no;
        ulint   zip_size;

        page = buf_block_get_frame(block);

        if (!page_is_leaf(page)) {

                return;
        }

        mtr_start(&mtr);

        space = buf_block_get_space(block);
        page_no = buf_block_get_page_no(block);
        zip_size = buf_block_get_zip_size(block);
        bitmap_page = ibuf_bitmap_get_map_page(space, page_no, zip_size, &mtr);

#ifdef UNIV_IBUF_DEBUG
        if (max_val != ULINT_UNDEFINED) {
                ulint   old_val;

                old_val = ibuf_bitmap_page_get_bits(
                        bitmap_page, page_no, zip_size,
                        IBUF_BITMAP_FREE, &mtr);
# if 0
                if (old_val != max_val) {
                        fprintf(stderr,
                                "Ibuf: page %lu old val %lu max val %lu\n",
                                page_get_page_no(page),
                                old_val, max_val);
                }
# endif

                ut_a(old_val <= max_val);
        }
# if 0
        fprintf(stderr, "Setting page no %lu free bits to %lu should be %lu\n",
                page_get_page_no(page), val,
                ibuf_index_page_calc_free(zip_size, block));
# endif

        ut_a(val <= ibuf_index_page_calc_free(zip_size, block));
#endif /* UNIV_IBUF_DEBUG */
        ibuf_bitmap_page_set_bits(bitmap_page, page_no, zip_size,
                                  IBUF_BITMAP_FREE, val, &mtr);
        mtr_commit(&mtr);
}

/************************************************************************//**
Resets the free bits of the page in the ibuf bitmap. This is done in a
separate mini-transaction, hence this operation does not restrict
further work to only ibuf bitmap operations, which would result if the
latch to the bitmap page were kept.  NOTE: The free bits in the insert
buffer bitmap must never exceed the free space on a page.  It is safe
to decrement or reset the bits in the bitmap in a mini-transaction
that is committed before the mini-transaction that affects the free
space. */
UNIV_INTERN
void
ibuf_reset_free_bits(
/*=================*/
        buf_block_t*    block)  /*!< in: index page; free bits are set to 0
                                if the index is a non-clustered
                                non-unique, and page level is 0 */
{
        ibuf_set_free_bits(block, 0, ULINT_UNDEFINED);
}

/**********************************************************************//**
Updates the free bits for an uncompressed page to reflect the present
state.  Does this in the mtr given, which means that the latching
order rules virtually prevent any further operations for this OS
thread until mtr is committed.  NOTE: The free bits in the insert
buffer bitmap must never exceed the free space on a page.  It is safe
to set the free bits in the same mini-transaction that updated the
page. */
UNIV_INTERN
void
ibuf_update_free_bits_low(
/*======================*/
        const buf_block_t*      block,          /*!< in: index page */
        ulint                   max_ins_size,   /*!< in: value of
                                                maximum insert size
                                                with reorganize before
                                                the latest operation
                                                performed to the page */
        mtr_t*                  mtr)            /*!< in/out: mtr */
{
        ulint   before;
        ulint   after;

        ut_a(!buf_block_get_page_zip(block));

        before = ibuf_index_page_calc_free_bits(0, max_ins_size);

        after = ibuf_index_page_calc_free(0, block);

        /* This approach cannot be used on compressed pages, since the
        computed value of "before" often does not match the current
        state of the bitmap.  This is because the free space may
        increase or decrease when a compressed page is reorganized. */
        if (before != after) {
                ibuf_set_free_bits_low(0, block, after, mtr);
        }
}

/**********************************************************************//**
Updates the free bits for a compressed page to reflect the present
state.  Does this in the mtr given, which means that the latching
order rules virtually prevent any further operations for this OS
thread until mtr is committed.  NOTE: The free bits in the insert
buffer bitmap must never exceed the free space on a page.  It is safe
to set the free bits in the same mini-transaction that updated the
page. */
UNIV_INTERN
void
ibuf_update_free_bits_zip(
/*======================*/
        buf_block_t*    block,  /*!< in/out: index page */
        mtr_t*          mtr)    /*!< in/out: mtr */
{
        page_t* bitmap_page;
        ulint   space;
        ulint   page_no;
        ulint   zip_size;
        ulint   after;

        space = buf_block_get_space(block);
        page_no = buf_block_get_page_no(block);
        zip_size = buf_block_get_zip_size(block);

        ut_a(page_is_leaf(buf_block_get_frame(block)));
        ut_a(zip_size);

        bitmap_page = ibuf_bitmap_get_map_page(space, page_no, zip_size, mtr);

        after = ibuf_index_page_calc_free_zip(zip_size, block);

        if (after == 0) {
                /* We move the page to the front of the buffer pool LRU list:
                the purpose of this is to prevent those pages to which we
                cannot make inserts using the insert buffer from slipping
                out of the buffer pool */

                buf_page_make_young(&block->page);
        }

        ibuf_bitmap_page_set_bits(bitmap_page, page_no, zip_size,
                                  IBUF_BITMAP_FREE, after, mtr);
}

/**********************************************************************//**
Updates the free bits for the two pages to reflect the present state.
Does this in the mtr given, which means that the latching order rules
virtually prevent any further operations until mtr is committed.
NOTE: The free bits in the insert buffer bitmap must never exceed the
free space on a page.  It is safe to set the free bits in the same
mini-transaction that updated the pages. */
UNIV_INTERN
void
ibuf_update_free_bits_for_two_pages_low(
/*====================================*/
        ulint           zip_size,/*!< in: compressed page size in bytes;
                                0 for uncompressed pages */
        buf_block_t*    block1, /*!< in: index page */
        buf_block_t*    block2, /*!< in: index page */
        mtr_t*          mtr)    /*!< in: mtr */
{
        ulint   state;

        /* As we have to x-latch two random bitmap pages, we have to acquire
        the bitmap mutex to prevent a deadlock with a similar operation
        performed by another OS thread. */

        mutex_enter(&ibuf_bitmap_mutex);

        state = ibuf_index_page_calc_free(zip_size, block1);

        ibuf_set_free_bits_low(zip_size, block1, state, mtr);

        state = ibuf_index_page_calc_free(zip_size, block2);

        ibuf_set_free_bits_low(zip_size, block2, state, mtr);

        mutex_exit(&ibuf_bitmap_mutex);
}

/**********************************************************************//**
Returns TRUE if the page is one of the fixed address ibuf pages.
@return TRUE if a fixed address ibuf i/o page */
UNIV_INLINE
ibool
ibuf_fixed_addr_page(
/*=================*/
        ulint   space,  /*!< in: space id */
        ulint   zip_size,/*!< in: compressed page size in bytes;
                        0 for uncompressed pages */
        ulint   page_no)/*!< in: page number */
{
        return((space == IBUF_SPACE_ID && page_no == IBUF_TREE_ROOT_PAGE_NO)
               || ibuf_bitmap_page(zip_size, page_no));
}

/***********************************************************************//**
Checks if a page is a level 2 or 3 page in the ibuf hierarchy of pages.
Must not be called when recv_no_ibuf_operations==TRUE.
@return TRUE if level 2 or level 3 page */
UNIV_INTERN
ibool
ibuf_page(
/*======*/
        ulint   space,  /*!< in: space id */
        ulint   zip_size,/*!< in: compressed page size in bytes, or 0 */
        ulint   page_no,/*!< in: page number */
        mtr_t*  mtr)    /*!< in: mtr which will contain an x-latch to the
                        bitmap page if the page is not one of the fixed
                        address ibuf pages, or NULL, in which case a new
                        transaction is created. */
{
        ibool   ret;
        mtr_t   local_mtr;
        page_t* bitmap_page;

        ut_ad(!recv_no_ibuf_operations);

        if (ibuf_fixed_addr_page(space, zip_size, page_no)) {

                return(TRUE);
        } else if (space != IBUF_SPACE_ID) {

                return(FALSE);
        }

        ut_ad(fil_space_get_type(IBUF_SPACE_ID) == FIL_TABLESPACE);

        if (mtr == NULL) {
                mtr = &local_mtr;
                mtr_start(mtr);
        }

        bitmap_page = ibuf_bitmap_get_map_page(space, page_no, zip_size, mtr);

        ret = ibuf_bitmap_page_get_bits(bitmap_page, page_no, zip_size,
                                        IBUF_BITMAP_IBUF, mtr);

        if (mtr == &local_mtr) {
                mtr_commit(mtr);
        }

        return(ret);
}

/********************************************************************//**
Returns the page number field of an ibuf record.
@return page number */
static
ulint
ibuf_rec_get_page_no(
/*=================*/
        const rec_t*    rec)    /*!< in: ibuf record */
{
        const byte*     field;
        ulint           len;

        ut_ad(ibuf_inside());
        ut_ad(rec_get_n_fields_old(rec) > 2);

        field = rec_get_nth_field_old(rec, 1, &len);

        if (len == 1) {
                /* This is of the >= 4.1.x record format */
                ut_a(trx_sys_multiple_tablespace_format);

                field = rec_get_nth_field_old(rec, 2, &len);
        } else {
                ut_a(trx_doublewrite_must_reset_space_ids);
                ut_a(!trx_sys_multiple_tablespace_format);

                field = rec_get_nth_field_old(rec, 0, &len);
        }

        ut_a(len == 4);

        return(mach_read_from_4(field));
}

/********************************************************************//**
Returns the space id field of an ibuf record. For < 4.1.x format records
returns 0.
@return space id */
static
ulint
ibuf_rec_get_space(
/*===============*/
        const rec_t*    rec)    /*!< in: ibuf record */
{
        const byte*     field;
        ulint           len;

        ut_ad(ibuf_inside());
        ut_ad(rec_get_n_fields_old(rec) > 2);

        field = rec_get_nth_field_old(rec, 1, &len);

        if (len == 1) {
                /* This is of the >= 4.1.x record format */

                ut_a(trx_sys_multiple_tablespace_format);
                field = rec_get_nth_field_old(rec, 0, &len);
                ut_a(len == 4);

                return(mach_read_from_4(field));
        }

        ut_a(trx_doublewrite_must_reset_space_ids);
        ut_a(!trx_sys_multiple_tablespace_format);

        return(0);
}

/********************************************************************//**
Creates a dummy index for inserting a record to a non-clustered index.

@return dummy index */
static
dict_index_t*
ibuf_dummy_index_create(
/*====================*/
        ulint           n,      /*!< in: number of fields */
        ibool           comp)   /*!< in: TRUE=use compact record format */
{
        dict_table_t*   table;
        dict_index_t*   index;

        table = dict_mem_table_create("IBUF_DUMMY",
                                      DICT_HDR_SPACE, n,
                                      comp ? DICT_TF_COMPACT : 0);

        index = dict_mem_index_create("IBUF_DUMMY", "IBUF_DUMMY",
                                      DICT_HDR_SPACE, 0, n);

        index->table = table;

        /* avoid ut_ad(index->cached) in dict_index_get_n_unique_in_tree */
        index->cached = TRUE;

        return(index);
}
/********************************************************************//**
Add a column to the dummy index */
static
void
ibuf_dummy_index_add_col(
/*=====================*/
        dict_index_t*   index,  /*!< in: dummy index */
        const dtype_t*  type,   /*!< in: the data type of the column */
        ulint           len)    /*!< in: length of the column */
{
        ulint   i       = index->table->n_def;
        dict_mem_table_add_col(index->table, NULL, NULL,
                               dtype_get_mtype(type),
                               dtype_get_prtype(type),
                               dtype_get_len(type));
        dict_index_add_col(index, index->table,
                           dict_table_get_nth_col(index->table, i), len);
}
/********************************************************************//**
Deallocates a dummy index for inserting a record to a non-clustered index. */
static
void
ibuf_dummy_index_free(
/*==================*/
        dict_index_t*   index)  /*!< in, own: dummy index */
{
        dict_table_t*   table = index->table;

        dict_mem_index_free(index);
        dict_mem_table_free(table);
}

/*********************************************************************//**
Builds the entry to insert into a non-clustered index when we have the
corresponding record in an ibuf index.

NOTE that as we copy pointers to fields in ibuf_rec, the caller must
hold a latch to the ibuf_rec page as long as the entry is used!

@return own: entry to insert to a non-clustered index */
UNIV_INLINE
dtuple_t*
ibuf_build_entry_pre_4_1_x(
/*=======================*/
        const rec_t*    ibuf_rec,       /*!< in: record in an insert buffer */
        mem_heap_t*     heap,           /*!< in: heap where built */
        dict_index_t**  pindex)         /*!< out, own: dummy index that
                                        describes the entry */
{
        ulint           i;
        ulint           len;
        const byte*     types;
        dtuple_t*       tuple;
        ulint           n_fields;

        ut_a(trx_doublewrite_must_reset_space_ids);
        ut_a(!trx_sys_multiple_tablespace_format);

        n_fields = rec_get_n_fields_old(ibuf_rec) - 2;
        tuple = dtuple_create(heap, n_fields);
        types = rec_get_nth_field_old(ibuf_rec, 1, &len);

        ut_a(len == n_fields * DATA_ORDER_NULL_TYPE_BUF_SIZE);

        for (i = 0; i < n_fields; i++) {
                const byte*     data;
                dfield_t*       field;

                field = dtuple_get_nth_field(tuple, i);

                data = rec_get_nth_field_old(ibuf_rec, i + 2, &len);

                dfield_set_data(field, data, len);

                dtype_read_for_order_and_null_size(
                        dfield_get_type(field),
                        types + i * DATA_ORDER_NULL_TYPE_BUF_SIZE);
        }

        *pindex = ibuf_dummy_index_create(n_fields, FALSE);

        return(tuple);
}

/*********************************************************************//**
Builds the entry to insert into a non-clustered index when we have the
corresponding record in an ibuf index.

NOTE that as we copy pointers to fields in ibuf_rec, the caller must
hold a latch to the ibuf_rec page as long as the entry is used!

@return own: entry to insert to a non-clustered index */
static
dtuple_t*
ibuf_build_entry_from_ibuf_rec(
/*===========================*/
        const rec_t*    ibuf_rec,       /*!< in: record in an insert buffer */
        mem_heap_t*     heap,           /*!< in: heap where built */
        dict_index_t**  pindex)         /*!< out, own: dummy index that
                                        describes the entry */
{
        dtuple_t*       tuple;
        dfield_t*       field;
        ulint           n_fields;
        const byte*     types;
        const byte*     data;
        ulint           len;
        ulint           i;
        dict_index_t*   index;

        data = rec_get_nth_field_old(ibuf_rec, 1, &len);

        if (len > 1) {
                /* This a < 4.1.x format record */

                return(ibuf_build_entry_pre_4_1_x(ibuf_rec, heap, pindex));
        }

        /* This a >= 4.1.x format record */

        ut_a(trx_sys_multiple_tablespace_format);
        ut_a(*data == 0);
        ut_a(rec_get_n_fields_old(ibuf_rec) > 4);

        n_fields = rec_get_n_fields_old(ibuf_rec) - 4;

        tuple = dtuple_create(heap, n_fields);

        types = rec_get_nth_field_old(ibuf_rec, 3, &len);

        ut_a(len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE <= 1);
        index = ibuf_dummy_index_create(
                n_fields, len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);

        if (len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE) {
                /* compact record format */
                len--;
                ut_a(*types == 0);
                types++;
        }

        ut_a(len == n_fields * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);

        for (i = 0; i < n_fields; i++) {
                field = dtuple_get_nth_field(tuple, i);

                data = rec_get_nth_field_old(ibuf_rec, i + 4, &len);

                dfield_set_data(field, data, len);

                dtype_new_read_for_order_and_null_size(
                        dfield_get_type(field),
                        types + i * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);

                ibuf_dummy_index_add_col(index, dfield_get_type(field), len);
        }

        /* Prevent an ut_ad() failure in page_zip_write_rec() by
        adding system columns to the dummy table pointed to by the
        dummy secondary index.  The insert buffer is only used for
        secondary indexes, whose records never contain any system
        columns, such as DB_TRX_ID. */
        ut_d(dict_table_add_system_columns(index->table, index->table->heap));

        *pindex = index;

        return(tuple);
}

/********************************************************************//**
Returns the space taken by a stored non-clustered index entry if converted to
an index record.
@return size of index record in bytes + an upper limit of the space
taken in the page directory */
static
ulint
ibuf_rec_get_volume(
/*================*/
        const rec_t*    ibuf_rec)/*!< in: ibuf record */
{
        dtype_t         dtype;
        ibool           new_format      = FALSE;
        ulint           data_size       = 0;
        ulint           n_fields;
        const byte*     types;
        const byte*     data;
        ulint           len;
        ulint           i;
        ulint           comp;

        ut_ad(ibuf_inside());
        ut_ad(rec_get_n_fields_old(ibuf_rec) > 2);

        data = rec_get_nth_field_old(ibuf_rec, 1, &len);

        if (len > 1) {
                /* < 4.1.x format record */

                ut_a(trx_doublewrite_must_reset_space_ids);
                ut_a(!trx_sys_multiple_tablespace_format);

                n_fields = rec_get_n_fields_old(ibuf_rec) - 2;

                types = rec_get_nth_field_old(ibuf_rec, 1, &len);

                ut_ad(len == n_fields * DATA_ORDER_NULL_TYPE_BUF_SIZE);
                comp = 0;
        } else {
                /* >= 4.1.x format record */

                ut_a(trx_sys_multiple_tablespace_format);
                ut_a(*data == 0);

                types = rec_get_nth_field_old(ibuf_rec, 3, &len);

                comp = len % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE;

                ut_a(comp <= 1);
                if (comp) {
                        /* compact record format */
                        ulint           volume;
                        dict_index_t*   dummy_index;
                        mem_heap_t*     heap = mem_heap_create(500);
                        dtuple_t*       entry = ibuf_build_entry_from_ibuf_rec(
                                ibuf_rec, heap, &dummy_index);
                        volume = rec_get_converted_size(dummy_index, entry, 0);
                        ibuf_dummy_index_free(dummy_index);
                        mem_heap_free(heap);
                        return(volume + page_dir_calc_reserved_space(1));
                }

                n_fields = rec_get_n_fields_old(ibuf_rec) - 4;

                new_format = TRUE;
        }

        for (i = 0; i < n_fields; i++) {
                if (new_format) {
                        data = rec_get_nth_field_old(ibuf_rec, i + 4, &len);

                        dtype_new_read_for_order_and_null_size(
                                &dtype, types + i
                                * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE);
                } else {
                        data = rec_get_nth_field_old(ibuf_rec, i + 2, &len);

                        dtype_read_for_order_and_null_size(
                                &dtype, types + i
                                * DATA_ORDER_NULL_TYPE_BUF_SIZE);
                }

                if (len == UNIV_SQL_NULL) {
                        data_size += dtype_get_sql_null_size(&dtype, comp);
                } else {
                        data_size += len;
                }
        }

        return(data_size + rec_get_converted_extra_size(data_size, n_fields, 0)
               + page_dir_calc_reserved_space(1));
}

/*********************************************************************//**
Builds the tuple to insert to an ibuf tree when we have an entry for a
non-clustered index.

NOTE that the original entry must be kept because we copy pointers to
its fields.

@return own: entry to insert into an ibuf index tree */
static
dtuple_t*
ibuf_entry_build(
/*=============*/
        dict_index_t*   index,  /*!< in: non-clustered index */
        const dtuple_t* entry,  /*!< in: entry for a non-clustered index */
        ulint           space,  /*!< in: space id */
        ulint           page_no,/*!< in: index page number where entry should
                                be inserted */
        mem_heap_t*     heap)   /*!< in: heap into which to build */
{
        dtuple_t*       tuple;
        dfield_t*       field;
        const dfield_t* entry_field;
        ulint           n_fields;
        byte*           buf;
        byte*           buf2;
        ulint           i;

        /* Starting from 4.1.x, we have to build a tuple whose
        (1) first field is the space id,
        (2) the second field a single marker byte (0) to tell that this
        is a new format record,
        (3) the third contains the page number, and
        (4) the fourth contains the relevent type information of each data
        field; the length of this field % DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE is
        (a) 0 for b-trees in the old format, and
        (b) 1 for b-trees in the compact format, the first byte of the field
        being the marker (0);
        (5) and the rest of the fields are copied from entry. All fields
        in the tuple are ordered like the type binary in our insert buffer
        tree. */

        n_fields = dtuple_get_n_fields(entry);

        tuple = dtuple_create(heap, n_fields + 4);

        /* Store the space id in tuple */

        field = dtuple_get_nth_field(tuple, 0);

        buf = mem_heap_alloc(heap, 4);

        mach_write_to_4(buf, space);

        dfield_set_data(field, buf, 4);

        /* Store the marker byte field in tuple */

        field = dtuple_get_nth_field(tuple, 1);

        buf = mem_heap_alloc(heap, 1);

        /* We set the marker byte zero */

        mach_write_to_1(buf, 0);

        dfield_set_data(field, buf, 1);

        /* Store the page number in tuple */

        field = dtuple_get_nth_field(tuple, 2);

        buf = mem_heap_alloc(heap, 4);

        mach_write_to_4(buf, page_no);

        dfield_set_data(field, buf, 4);

        /* Store the type info in buf2, and add the fields from entry to
        tuple */
        buf2 = mem_heap_alloc(heap, n_fields
                              * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE
                              + dict_table_is_comp(index->table));
        if (dict_table_is_comp(index->table)) {
                *buf2++ = 0; /* write the compact format indicator */
        }
        for (i = 0; i < n_fields; i++) {
                ulint                   fixed_len;
                const dict_field_t*     ifield;

                /* We add 4 below because we have the 4 extra fields at the
                start of an ibuf record */

                field = dtuple_get_nth_field(tuple, i + 4);
                entry_field = dtuple_get_nth_field(entry, i);
                dfield_copy(field, entry_field);

                ifield = dict_index_get_nth_field(index, i);
                /* Prefix index columns of fixed-length columns are of
                fixed length.  However, in the function call below,
                dfield_get_type(entry_field) contains the fixed length
                of the column in the clustered index.  Replace it with
                the fixed length of the secondary index column. */
                fixed_len = ifield->fixed_len;

#ifdef UNIV_DEBUG
                if (fixed_len) {
                        /* dict_index_add_col() should guarantee these */
                        ut_ad(fixed_len <= (ulint)
                              dfield_get_type(entry_field)->len);
                        if (ifield->prefix_len) {
                                ut_ad(ifield->prefix_len == fixed_len);
                        } else {
                                ut_ad(fixed_len == (ulint)
                                      dfield_get_type(entry_field)->len);
                        }
                }
#endif /* UNIV_DEBUG */

                dtype_new_store_for_order_and_null_size(
                        buf2 + i * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE,
                        dfield_get_type(entry_field), fixed_len);
        }

        /* Store the type info in buf2 to field 3 of tuple */

        field = dtuple_get_nth_field(tuple, 3);

        if (dict_table_is_comp(index->table)) {
                buf2--;
        }

        dfield_set_data(field, buf2, n_fields
                        * DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE
                        + dict_table_is_comp(index->table));
        /* Set all the types in the new tuple binary */

        dtuple_set_types_binary(tuple, n_fields + 4);

        return(tuple);
}

/*********************************************************************//**
Builds a search tuple used to search buffered inserts for an index page.
This is for < 4.1.x format records
@return own: search tuple */
static
dtuple_t*
ibuf_search_tuple_build(
/*====================*/
        ulint           space,  /*!< in: space id */
        ulint           page_no,/*!< in: index page number */
        mem_heap_t*     heap)   /*!< in: heap into which to build */
{
        dtuple_t*       tuple;
        dfield_t*       field;
        byte*           buf;

        ut_a(space == 0);
        ut_a(trx_doublewrite_must_reset_space_ids);
        ut_a(!trx_sys_multiple_tablespace_format);

        tuple = dtuple_create(heap, 1);

        /* Store the page number in tuple */

        field = dtuple_get_nth_field(tuple, 0);

        buf = mem_heap_alloc(heap, 4);

        mach_write_to_4(buf, page_no);

        dfield_set_data(field, buf, 4);

        dtuple_set_types_binary(tuple, 1);

        return(tuple);
}

/*********************************************************************//**
Builds a search tuple used to search buffered inserts for an index page.
This is for >= 4.1.x format records.
@return own: search tuple */
static
dtuple_t*
ibuf_new_search_tuple_build(
/*========================*/
        ulint           space,  /*!< in: space id */
        ulint           page_no,/*!< in: index page number */
        mem_heap_t*     heap)   /*!< in: heap into which to build */
{
        dtuple_t*       tuple;
        dfield_t*       field;
        byte*           buf;

        ut_a(trx_sys_multiple_tablespace_format);

        tuple = dtuple_create(heap, 3);

        /* Store the space id in tuple */

        field = dtuple_get_nth_field(tuple, 0);

        buf = mem_heap_alloc(heap, 4);

        mach_write_to_4(buf, space);

        dfield_set_data(field, buf, 4);

        /* Store the new format record marker byte */

        field = dtuple_get_nth_field(tuple, 1);

        buf = mem_heap_alloc(heap, 1);

        mach_write_to_1(buf, 0);

        dfield_set_data(field, buf, 1);

        /* Store the page number in tuple */

        field = dtuple_get_nth_field(tuple, 2);

        buf = mem_heap_alloc(heap, 4);

        mach_write_to_4(buf, page_no);

        dfield_set_data(field, buf, 4);

        dtuple_set_types_binary(tuple, 3);

        return(tuple);
}

/*********************************************************************//**
Checks if there are enough pages in the free list of the ibuf tree that we
dare to start a pessimistic insert to the insert buffer.
@return TRUE if enough free pages in list */
UNIV_INLINE
ibool
ibuf_data_enough_free_for_insert(void)
/*==================================*/
{
        ut_ad(mutex_own(&ibuf_mutex));

        /* We want a big margin of free pages, because a B-tree can sometimes
        grow in size also if records are deleted from it, as the node pointers
        can change, and we must make sure that we are able to delete the
        inserts buffered for pages that we read to the buffer pool, without
        any risk of running out of free space in the insert buffer. */

        return(ibuf->free_list_len >= (ibuf->size / 2) + 3 * ibuf->height);
}

/*********************************************************************//**
Checks if there are enough pages in the free list of the ibuf tree that we
should remove them and free to the file space management.
@return TRUE if enough free pages in list */
UNIV_INLINE
ibool
ibuf_data_too_much_free(void)
/*=========================*/
{
        ut_ad(mutex_own(&ibuf_mutex));

        return(ibuf->free_list_len >= 3 + (ibuf->size / 2) + 3 * ibuf->height);
}

/*********************************************************************//**
Allocates a new page from the ibuf file segment and adds it to the free
list.
@return DB_SUCCESS, or DB_STRONG_FAIL if no space left */
static
ulint
ibuf_add_free_page(void)
/*====================*/
{
        mtr_t           mtr;
        page_t*         header_page;
        ulint           flags;
        ulint           zip_size;
        buf_block_t*    block;
        page_t*         page;
        page_t*         root;
        page_t*         bitmap_page;

        mtr_start(&mtr);

        /* Acquire the fsp latch before the ibuf header, obeying the latching
        order */
        mtr_x_lock(fil_space_get_latch(IBUF_SPACE_ID, &flags), &mtr);
        zip_size = dict_table_flags_to_zip_size(flags);

        header_page = ibuf_header_page_get(&mtr);

        /* Allocate a new page: NOTE that if the page has been a part of a
        non-clustered index which has subsequently been dropped, then the
        page may have buffered inserts in the insert buffer, and these
        should be deleted from there. These get deleted when the page
        allocation creates the page in buffer. Thus the call below may end
        up calling the insert buffer routines and, as we yet have no latches
        to insert buffer tree pages, these routines can run without a risk
        of a deadlock. This is the reason why we created a special ibuf
        header page apart from the ibuf tree. */

        block = fseg_alloc_free_page(
                header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER, 0, FSP_UP,
                &mtr);

        if (block == NULL) {
                mtr_commit(&mtr);

                return(DB_STRONG_FAIL);
        }

        ut_ad(rw_lock_get_x_lock_count(&block->lock) == 1);
        ibuf_enter();
        mutex_enter(&ibuf_mutex);
        root = ibuf_tree_root_get(&mtr);

        buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE_NEW);
        page = buf_block_get_frame(block);

        /* Add the page to the free list and update the ibuf size data */

        flst_add_last(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
                      page + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, &mtr);

        mlog_write_ulint(page + FIL_PAGE_TYPE, FIL_PAGE_IBUF_FREE_LIST,
                         MLOG_2BYTES, &mtr);

        ibuf->seg_size++;
        ibuf->free_list_len++;

        /* Set the bit indicating that this page is now an ibuf tree page
        (level 2 page) */

        bitmap_page = ibuf_bitmap_get_map_page(
                IBUF_SPACE_ID, buf_block_get_page_no(block), zip_size, &mtr);

        ibuf_bitmap_page_set_bits(
                bitmap_page, buf_block_get_page_no(block), zip_size,
                IBUF_BITMAP_IBUF, TRUE, &mtr);

        mtr_commit(&mtr);

        mutex_exit(&ibuf_mutex);

        ibuf_exit();

        return(DB_SUCCESS);
}

/*********************************************************************//**
Removes a page from the free list and frees it to the fsp system. */
static
void
ibuf_remove_free_page(void)
/*=======================*/
{
        mtr_t   mtr;
        mtr_t   mtr2;
        page_t* header_page;
        ulint   flags;
        ulint   zip_size;
        ulint   page_no;
        page_t* page;
        page_t* root;
        page_t* bitmap_page;

        mtr_start(&mtr);

        /* Acquire the fsp latch before the ibuf header, obeying the latching
        order */
        mtr_x_lock(fil_space_get_latch(IBUF_SPACE_ID, &flags), &mtr);
        zip_size = dict_table_flags_to_zip_size(flags);

        header_page = ibuf_header_page_get(&mtr);

        /* Prevent pessimistic inserts to insert buffer trees for a while */
        mutex_enter(&ibuf_pessimistic_insert_mutex);

        ibuf_enter();

        mutex_enter(&ibuf_mutex);

        if (!ibuf_data_too_much_free()) {

                mutex_exit(&ibuf_mutex);

                ibuf_exit();

                mutex_exit(&ibuf_pessimistic_insert_mutex);

                mtr_commit(&mtr);

                return;
        }

        mtr_start(&mtr2);

        root = ibuf_tree_root_get(&mtr2);

        page_no = flst_get_last(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
                                &mtr2).page;

        /* NOTE that we must release the latch on the ibuf tree root
        because in fseg_free_page we access level 1 pages, and the root
        is a level 2 page. */

        mtr_commit(&mtr2);
        mutex_exit(&ibuf_mutex);

        ibuf_exit();

        /* Since pessimistic inserts were prevented, we know that the
        page is still in the free list. NOTE that also deletes may take
        pages from the free list, but they take them from the start, and
        the free list was so long that they cannot have taken the last
        page from it. */

        fseg_free_page(header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER,
                       IBUF_SPACE_ID, page_no, &mtr);

#if defined UNIV_DEBUG_FILE_ACCESSES || defined UNIV_DEBUG
        buf_page_reset_file_page_was_freed(IBUF_SPACE_ID, page_no);
#endif /* UNIV_DEBUG_FILE_ACCESSES || UNIV_DEBUG */

        ibuf_enter();

        mutex_enter(&ibuf_mutex);

        root = ibuf_tree_root_get(&mtr);

        ut_ad(page_no == flst_get_last(root + PAGE_HEADER
                                       + PAGE_BTR_IBUF_FREE_LIST, &mtr).page);

        {
                buf_block_t*    block;

                block = buf_page_get(
                        IBUF_SPACE_ID, 0, page_no, RW_X_LATCH, &mtr);

                buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);

                page = buf_block_get_frame(block);
        }

        /* Remove the page from the free list and update the ibuf size data */

        flst_remove(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
                    page + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, &mtr);

        ibuf->seg_size--;
        ibuf->free_list_len--;

        mutex_exit(&ibuf_pessimistic_insert_mutex);

        /* Set the bit indicating that this page is no more an ibuf tree page
        (level 2 page) */

        bitmap_page = ibuf_bitmap_get_map_page(
                IBUF_SPACE_ID, page_no, zip_size, &mtr);

        ibuf_bitmap_page_set_bits(
                bitmap_page, page_no, zip_size, IBUF_BITMAP_IBUF, FALSE, &mtr);

#if defined UNIV_DEBUG_FILE_ACCESSES || defined UNIV_DEBUG
        buf_page_set_file_page_was_freed(IBUF_SPACE_ID, page_no);
#endif /* UNIV_DEBUG_FILE_ACCESSES || UNIV_DEBUG */
        mtr_commit(&mtr);

        mutex_exit(&ibuf_mutex);

        ibuf_exit();
}

/***********************************************************************//**
Frees excess pages from the ibuf free list. This function is called when an OS
thread calls fsp services to allocate a new file segment, or a new page to a
file segment, and the thread did not own the fsp latch before this call. */
UNIV_INTERN
void
ibuf_free_excess_pages(void)
/*========================*/
{
        ulint           i;

#ifdef UNIV_SYNC_DEBUG
        ut_ad(rw_lock_own(fil_space_get_latch(IBUF_SPACE_ID, NULL),
                          RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */

        ut_ad(rw_lock_get_x_lock_count(
                fil_space_get_latch(IBUF_SPACE_ID, NULL)) == 1);

        ut_ad(!ibuf_inside());

        /* NOTE: We require that the thread did not own the latch before,
        because then we know that we can obey the correct latching order
        for ibuf latches */

        if (!ibuf) {
                /* Not yet initialized; not sure if this is possible, but
                does no harm to check for it. */

                return;
        }

        /* Free at most a few pages at a time, so that we do not delay the
        requested service too much */

        for (i = 0; i < 4; i++) {

                mutex_enter(&ibuf_mutex);

                if (!ibuf_data_too_much_free()) {

                        mutex_exit(&ibuf_mutex);

                        return;
                }

                mutex_exit(&ibuf_mutex);

                ibuf_remove_free_page();
        }
}

/*********************************************************************//**
Reads page numbers from a leaf in an ibuf tree.
@return a lower limit for the combined volume of records which will be
merged */
static
ulint
ibuf_get_merge_page_nos(
/*====================*/
        ibool           contract,/*!< in: TRUE if this function is called to
                                contract the tree, FALSE if this is called
                                when a single page becomes full and we look
                                if it pays to read also nearby pages */
        rec_t*          rec,    /*!< in: record from which we read up and down
                                in the chain of records */
        ulint*          space_ids,/*!< in/out: space id's of the pages */
        ib_int64_t*     space_versions,/*!< in/out: tablespace version
                                timestamps; used to prevent reading in old
                                pages after DISCARD + IMPORT tablespace */
        ulint*          page_nos,/*!< in/out: buffer for at least
                                IBUF_MAX_N_PAGES_MERGED many page numbers;
                                the page numbers are in an ascending order */
        ulint*          n_stored)/*!< out: number of page numbers stored to
                                page_nos in this function */
{
        ulint   prev_page_no;
        ulint   prev_space_id;
        ulint   first_page_no;
        ulint   first_space_id;
        ulint   rec_page_no;
        ulint   rec_space_id;
        ulint   sum_volumes;
        ulint   volume_for_page;
        ulint   rec_volume;
        ulint   limit;
        ulint   n_pages;

        *n_stored = 0;

        limit = ut_min(IBUF_MAX_N_PAGES_MERGED, buf_pool->curr_size / 4);

        if (page_rec_is_supremum(rec)) {

                rec = page_rec_get_prev(rec);
        }

        if (page_rec_is_infimum(rec)) {

                rec = page_rec_get_next(rec);
        }

        if (page_rec_is_supremum(rec)) {

                return(0);
        }

        first_page_no = ibuf_rec_get_page_no(rec);
        first_space_id = ibuf_rec_get_space(rec);
        n_pages = 0;
        prev_page_no = 0;
        prev_space_id = 0;

        /* Go backwards from the first rec until we reach the border of the
        'merge area', or the page start or the limit of storeable pages is
        reached */

        while (!page_rec_is_infimum(rec) && UNIV_LIKELY(n_pages < limit)) {

                rec_page_no = ibuf_rec_get_page_no(rec);
                rec_space_id = ibuf_rec_get_space(rec);

                if (rec_space_id != first_space_id
                    || (rec_page_no / IBUF_MERGE_AREA)
                    != (first_page_no / IBUF_MERGE_AREA)) {

                        break;
                }

                if (rec_page_no != prev_page_no
                    || rec_space_id != prev_space_id) {
                        n_pages++;
                }

                prev_page_no = rec_page_no;
                prev_space_id = rec_space_id;

                rec = page_rec_get_prev(rec);
        }

        rec = page_rec_get_next(rec);

        /* At the loop start there is no prev page; we mark this with a pair
        of space id, page no (0, 0) for which there can never be entries in
        the insert buffer */

        prev_page_no = 0;
        prev_space_id = 0;
        sum_volumes = 0;
        volume_for_page = 0;

        while (*n_stored < limit) {
                if (page_rec_is_supremum(rec)) {
                        /* When no more records available, mark this with
                        another 'impossible' pair of space id, page no */
                        rec_page_no = 1;
                        rec_space_id = 0;
                } else {
                        rec_page_no = ibuf_rec_get_page_no(rec);
                        rec_space_id = ibuf_rec_get_space(rec);
                        /* In the system tablespace, the smallest
                        possible secondary index leaf page number is
                        bigger than IBUF_TREE_ROOT_PAGE_NO (4). In
                        other tablespaces, the clustered index tree is
                        created at page 3, which makes page 4 the
                        smallest possible secondary index leaf page
                        (and that only after DROP INDEX). */
                        ut_ad(rec_page_no
                              > IBUF_TREE_ROOT_PAGE_NO - (rec_space_id != 0));
                }

#ifdef UNIV_IBUF_DEBUG
                ut_a(*n_stored < IBUF_MAX_N_PAGES_MERGED);
#endif
                if ((rec_space_id != prev_space_id
                     || rec_page_no != prev_page_no)
                    && (prev_space_id != 0 || prev_page_no != 0)) {

                        if ((prev_page_no == first_page_no
                             && prev_space_id == first_space_id)
                            || contract
                            || (volume_for_page
                                > ((IBUF_MERGE_THRESHOLD - 1)
                                   * 4 * UNIV_PAGE_SIZE
                                   / IBUF_PAGE_SIZE_PER_FREE_SPACE)
                                / IBUF_MERGE_THRESHOLD)) {

                                space_ids[*n_stored] = prev_space_id;
                                space_versions[*n_stored]
                                        = fil_space_get_version(prev_space_id);
                                page_nos[*n_stored] = prev_page_no;

                                (*n_stored)++;

                                sum_volumes += volume_for_page;
                        }

                        if (rec_space_id != first_space_id
                            || rec_page_no / IBUF_MERGE_AREA
                            != first_page_no / IBUF_MERGE_AREA) {

                                break;
                        }

                        volume_for_page = 0;
                }

                if (rec_page_no == 1 && rec_space_id == 0) {
                        /* Supremum record */

                        break;
                }

                rec_volume = ibuf_rec_get_volume(rec);

                volume_for_page += rec_volume;

                prev_page_no = rec_page_no;
                prev_space_id = rec_space_id;

                rec = page_rec_get_next(rec);
        }

#ifdef UNIV_IBUF_DEBUG
        ut_a(*n_stored <= IBUF_MAX_N_PAGES_MERGED);
#endif
#if 0
        fprintf(stderr, "Ibuf merge batch %lu pages %lu volume\n",
                *n_stored, sum_volumes);
#endif
        return(sum_volumes);
}

/*********************************************************************//**
Contracts insert buffer trees by reading pages to the buffer pool.
@return a lower limit for the combined size in bytes of entries which
will be merged from ibuf trees to the pages read, 0 if ibuf is
empty */
static
ulint
ibuf_contract_ext(
/*==============*/
        ulint*  n_pages,/*!< out: number of pages to which merged */
        ibool   sync)   /*!< in: TRUE if the caller wants to wait for the
                        issued read with the highest tablespace address
                        to complete */
{
        btr_pcur_t      pcur;
        ulint           page_nos[IBUF_MAX_N_PAGES_MERGED];
        ulint           space_ids[IBUF_MAX_N_PAGES_MERGED];
        ib_int64_t      space_versions[IBUF_MAX_N_PAGES_MERGED];
        ulint           n_stored;
        ulint           sum_sizes;
        mtr_t           mtr;

        *n_pages = 0;
        ut_ad(!ibuf_inside());

        mutex_enter(&ibuf_mutex);

        if (ibuf->empty) {
ibuf_is_empty:
                mutex_exit(&ibuf_mutex);

                return(0);
        }

        mtr_start(&mtr);

        ibuf_enter();

        /* Open a cursor to a randomly chosen leaf of the tree, at a random
        position within the leaf */

        btr_pcur_open_at_rnd_pos(ibuf->index, BTR_SEARCH_LEAF, &pcur, &mtr);

        if (page_get_n_recs(btr_pcur_get_page(&pcur)) == 0) {
                /* When the ibuf tree is emptied completely, the last record
                is removed using an optimistic delete and ibuf_size_update
                is not called, causing ibuf->empty to remain FALSE. If we do
                not reset it to TRUE here then database shutdown will hang
                in the loop in ibuf_contract_for_n_pages. */

                ibuf->empty = TRUE;

                ibuf_exit();

                mtr_commit(&mtr);
                btr_pcur_close(&pcur);

                goto ibuf_is_empty;
        }

        mutex_exit(&ibuf_mutex);

        sum_sizes = ibuf_get_merge_page_nos(TRUE, btr_pcur_get_rec(&pcur),
                                            space_ids, space_versions,
                                            page_nos, &n_stored);
#if 0 /* defined UNIV_IBUF_DEBUG */
        fprintf(stderr, "Ibuf contract sync %lu pages %lu volume %lu\n",
                sync, n_stored, sum_sizes);
#endif
        ibuf_exit();

        mtr_commit(&mtr);
        btr_pcur_close(&pcur);

        buf_read_ibuf_merge_pages(sync, space_ids, space_versions, page_nos,
                                  n_stored);
        *n_pages = n_stored;

        return(sum_sizes + 1);
}

/*********************************************************************//**
Contracts insert buffer trees by reading pages to the buffer pool.
@return a lower limit for the combined size in bytes of entries which
will be merged from ibuf trees to the pages read, 0 if ibuf is
empty */
UNIV_INTERN
ulint
ibuf_contract(
/*==========*/
        ibool   sync)   /*!< in: TRUE if the caller wants to wait for the
                        issued read with the highest tablespace address
                        to complete */
{
        ulint   n_pages;

        return(ibuf_contract_ext(&n_pages, sync));
}

/*********************************************************************//**
Contracts insert buffer trees by reading pages to the buffer pool.
@return a lower limit for the combined size in bytes of entries which
will be merged from ibuf trees to the pages read, 0 if ibuf is
empty */
UNIV_INTERN
ulint
ibuf_contract_for_n_pages(
/*======================*/
        ibool   sync,   /*!< in: TRUE if the caller wants to wait for the
                        issued read with the highest tablespace address
                        to complete */
        ulint   n_pages)/*!< in: try to read at least this many pages to
                        the buffer pool and merge the ibuf contents to
                        them */
{
        ulint   sum_bytes       = 0;
        ulint   sum_pages       = 0;
        ulint   n_bytes;
        ulint   n_pag2;

        while (sum_pages < n_pages) {
                n_bytes = ibuf_contract_ext(&n_pag2, sync);

                if (n_bytes == 0) {
                        return(sum_bytes);
                }

                sum_bytes += n_bytes;
                sum_pages += n_pag2;
        }

        return(sum_bytes);
}

/*********************************************************************//**
Contract insert buffer trees after insert if they are too big. */
UNIV_INLINE
void
ibuf_contract_after_insert(
/*=======================*/
        ulint   entry_size)     /*!< in: size of a record which was inserted
                                into an ibuf tree */
{
        ibool   sync;
        ulint   sum_sizes;
        ulint   size;

        mutex_enter(&ibuf_mutex);

        if (ibuf->size < ibuf->max_size + IBUF_CONTRACT_ON_INSERT_NON_SYNC) {
                mutex_exit(&ibuf_mutex);

                return;
        }

        sync = FALSE;

        if (ibuf->size >= ibuf->max_size + IBUF_CONTRACT_ON_INSERT_SYNC) {

                sync = TRUE;
        }

        mutex_exit(&ibuf_mutex);

        /* Contract at least entry_size many bytes */
        sum_sizes = 0;
        size = 1;

        while ((size > 0) && (sum_sizes < entry_size)) {

                size = ibuf_contract(sync);
                sum_sizes += size;
        }
}

/*********************************************************************//**
Gets an upper limit for the combined size of entries buffered in the insert
buffer for a given page.
@return upper limit for the volume of buffered inserts for the index
page, in bytes; UNIV_PAGE_SIZE, if the entries for the index page span
several pages in the insert buffer */
static
ulint
ibuf_get_volume_buffered(
/*=====================*/
        btr_pcur_t*     pcur,   /*!< in: pcur positioned at a place in an
                                insert buffer tree where we would insert an
                                entry for the index page whose number is
                                page_no, latch mode has to be BTR_MODIFY_PREV
                                or BTR_MODIFY_TREE */
        ulint           space,  /*!< in: space id */
        ulint           page_no,/*!< in: page number of an index page */
        mtr_t*          mtr)    /*!< in: mtr */
{
        ulint   volume;
        rec_t*  rec;
        page_t* page;
        ulint   prev_page_no;
        page_t* prev_page;
        ulint   next_page_no;
        page_t* next_page;

        ut_a(trx_sys_multiple_tablespace_format);

        ut_ad((pcur->latch_mode == BTR_MODIFY_PREV)
              || (pcur->latch_mode == BTR_MODIFY_TREE));

        /* Count the volume of records earlier in the alphabetical order than
        pcur */

        volume = 0;

        rec = btr_pcur_get_rec(pcur);
        page = page_align(rec);

        if (page_rec_is_supremum(rec)) {
                rec = page_rec_get_prev(rec);
        }

        for (;;) {
                if (page_rec_is_infimum(rec)) {

                        break;
                }

                if (page_no != ibuf_rec_get_page_no(rec)
                    || space != ibuf_rec_get_space(rec)) {

                        goto count_later;
                }

                volume += ibuf_rec_get_volume(rec);

                rec = page_rec_get_prev(rec);
        }

        /* Look at the previous page */

        prev_page_no = btr_page_get_prev(page, mtr);

        if (prev_page_no == FIL_NULL) {

                goto count_later;
        }

        {
                buf_block_t*    block;

                block = buf_page_get(
                        IBUF_SPACE_ID, 0, prev_page_no, RW_X_LATCH, mtr);

                buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);


                prev_page = buf_block_get_frame(block);
        }

#ifdef UNIV_BTR_DEBUG
        ut_a(btr_page_get_next(prev_page, mtr)
             == page_get_page_no(page));
#endif /* UNIV_BTR_DEBUG */

        rec = page_get_supremum_rec(prev_page);
        rec = page_rec_get_prev(rec);

        for (;;) {
                if (page_rec_is_infimum(rec)) {

                        /* We cannot go to yet a previous page, because we
                        do not have the x-latch on it, and cannot acquire one
                        because of the latching order: we have to give up */

                        return(UNIV_PAGE_SIZE);
                }

                if (page_no != ibuf_rec_get_page_no(rec)
                    || space != ibuf_rec_get_space(rec)) {

                        goto count_later;
                }

                volume += ibuf_rec_get_volume(rec);

                rec = page_rec_get_prev(rec);
        }

count_later:
        rec = btr_pcur_get_rec(pcur);

        if (!page_rec_is_supremum(rec)) {
                rec = page_rec_get_next(rec);
        }

        for (;;) {
                if (page_rec_is_supremum(rec)) {

                        break;
                }

                if (page_no != ibuf_rec_get_page_no(rec)
                    || space != ibuf_rec_get_space(rec)) {

                        return(volume);
                }

                volume += ibuf_rec_get_volume(rec);

                rec = page_rec_get_next(rec);
        }

        /* Look at the next page */

        next_page_no = btr_page_get_next(page, mtr);

        if (next_page_no == FIL_NULL) {

                return(volume);
        }

        {
                buf_block_t*    block;

                block = buf_page_get(
                        IBUF_SPACE_ID, 0, next_page_no, RW_X_LATCH, mtr);

                buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);


                next_page = buf_block_get_frame(block);
        }

#ifdef UNIV_BTR_DEBUG
        ut_a(btr_page_get_prev(next_page, mtr) == page_get_page_no(page));
#endif /* UNIV_BTR_DEBUG */

        rec = page_get_infimum_rec(next_page);
        rec = page_rec_get_next(rec);

        for (;;) {
                if (page_rec_is_supremum(rec)) {

                        /* We give up */

                        return(UNIV_PAGE_SIZE);
                }

                if (page_no != ibuf_rec_get_page_no(rec)
                    || space != ibuf_rec_get_space(rec)) {

                        return(volume);
                }

                volume += ibuf_rec_get_volume(rec);

                rec = page_rec_get_next(rec);
        }
}

/*********************************************************************//**
Reads the biggest tablespace id from the high end of the insert buffer
tree and updates the counter in fil_system. */
UNIV_INTERN
void
ibuf_update_max_tablespace_id(void)
/*===============================*/
{
        ulint           max_space_id;
        const rec_t*    rec;
        const byte*     field;
        ulint           len;
        btr_pcur_t      pcur;
        mtr_t           mtr;

        ut_a(!dict_table_is_comp(ibuf->index->table));

        ibuf_enter();

        mtr_start(&mtr);

        btr_pcur_open_at_index_side(
                FALSE, ibuf->index, BTR_SEARCH_LEAF, &pcur, TRUE, &mtr);

        btr_pcur_move_to_prev(&pcur, &mtr);

        if (btr_pcur_is_before_first_on_page(&pcur)) {
                /* The tree is empty */

                max_space_id = 0;
        } else {
                rec = btr_pcur_get_rec(&pcur);

                field = rec_get_nth_field_old(rec, 0, &len);

                ut_a(len == 4);

                max_space_id = mach_read_from_4(field);
        }

        mtr_commit(&mtr);
        ibuf_exit();

        /* printf("Maximum space id in insert buffer %lu\n", max_space_id); */

        fil_set_max_space_id_if_bigger(max_space_id);
}

/*********************************************************************//**
Makes an index insert to the insert buffer, instead of directly to the disk
page, if this is possible.
@return DB_SUCCESS, DB_FAIL, DB_STRONG_FAIL */
static
ulint
ibuf_insert_low(
/*============*/
        ulint           mode,   /*!< in: BTR_MODIFY_PREV or BTR_MODIFY_TREE */
        const dtuple_t* entry,  /*!< in: index entry to insert */
        ulint           entry_size,
                                /*!< in: rec_get_converted_size(index, entry) */
        dict_index_t*   index,  /*!< in: index where to insert; must not be
                                unique or clustered */
        ulint           space,  /*!< in: space id where to insert */
        ulint           zip_size,/*!< in: compressed page size in bytes, or 0 */
        ulint           page_no,/*!< in: page number where to insert */
        que_thr_t*      thr)    /*!< in: query thread */
{
        big_rec_t*      dummy_big_rec;
        btr_pcur_t      pcur;
        btr_cur_t*      cursor;
        dtuple_t*       ibuf_entry;
        mem_heap_t*     heap;
        ulint           buffered;
        rec_t*          ins_rec;
        ibool           old_bit_value;
        page_t*         bitmap_page;
        page_t*         root;
        ulint           err;
        ibool           do_merge;
        ulint           space_ids[IBUF_MAX_N_PAGES_MERGED];
        ib_int64_t      space_versions[IBUF_MAX_N_PAGES_MERGED];
        ulint           page_nos[IBUF_MAX_N_PAGES_MERGED];
        ulint           n_stored;
        ulint           bits;
        mtr_t           mtr;
        mtr_t           bitmap_mtr;

        ut_a(!dict_index_is_clust(index));
        ut_ad(dtuple_check_typed(entry));
        ut_ad(ut_is_2pow(zip_size));

        ut_a(trx_sys_multiple_tablespace_format);

        do_merge = FALSE;

        mutex_enter(&ibuf_mutex);

        if (ibuf->size >= ibuf->max_size + IBUF_CONTRACT_DO_NOT_INSERT) {
                /* Insert buffer is now too big, contract it but do not try
                to insert */

                mutex_exit(&ibuf_mutex);

#ifdef UNIV_IBUF_DEBUG
                fputs("Ibuf too big\n", stderr);
#endif
                /* Use synchronous contract (== TRUE) */
                ibuf_contract(TRUE);

                return(DB_STRONG_FAIL);
        }

        mutex_exit(&ibuf_mutex);

        if (mode == BTR_MODIFY_TREE) {
                mutex_enter(&ibuf_pessimistic_insert_mutex);

                ibuf_enter();

                mutex_enter(&ibuf_mutex);

                while (!ibuf_data_enough_free_for_insert()) {

                        mutex_exit(&ibuf_mutex);

                        ibuf_exit();

                        mutex_exit(&ibuf_pessimistic_insert_mutex);

                        err = ibuf_add_free_page();

                        if (err == DB_STRONG_FAIL) {

                                return(err);
                        }

                        mutex_enter(&ibuf_pessimistic_insert_mutex);

                        ibuf_enter();

                        mutex_enter(&ibuf_mutex);
                }
        } else {
                ibuf_enter();
        }

        heap = mem_heap_create(512);

        /* Build the entry which contains the space id and the page number as
        the first fields and the type information for other fields, and which
        will be inserted to the insert buffer. */

        ibuf_entry = ibuf_entry_build(index, entry, space, page_no, heap);

        /* Open a cursor to the insert buffer tree to calculate if we can add
        the new entry to it without exceeding the free space limit for the
        page. */

        mtr_start(&mtr);

        btr_pcur_open(ibuf->index, ibuf_entry, PAGE_CUR_LE, mode, &pcur, &mtr);

        /* Find out the volume of already buffered inserts for the same index
        page */
        buffered = ibuf_get_volume_buffered(&pcur, space, page_no, &mtr);

#ifdef UNIV_IBUF_COUNT_DEBUG
        ut_a((buffered == 0) || ibuf_count_get(space, page_no));
#endif
        mtr_start(&bitmap_mtr);

        bitmap_page = ibuf_bitmap_get_map_page(space, page_no,
                                               zip_size, &bitmap_mtr);

        /* We check if the index page is suitable for buffered entries */

        if (buf_page_peek(space, page_no)
            || lock_rec_expl_exist_on_page(space, page_no)) {
                err = DB_STRONG_FAIL;

                mtr_commit(&bitmap_mtr);

                goto function_exit;
        }

        bits = ibuf_bitmap_page_get_bits(bitmap_page, page_no, zip_size,
                                         IBUF_BITMAP_FREE, &bitmap_mtr);

        if (buffered + entry_size + page_dir_calc_reserved_space(1)
            > ibuf_index_page_calc_free_from_bits(zip_size, bits)) {
                mtr_commit(&bitmap_mtr);

                /* It may not fit */
                err = DB_STRONG_FAIL;

                do_merge = TRUE;

                ibuf_get_merge_page_nos(FALSE, btr_pcur_get_rec(&pcur),
                                        space_ids, space_versions,
                                        page_nos, &n_stored);
                goto function_exit;
        }

        /* Set the bitmap bit denoting that the insert buffer contains
        buffered entries for this index page, if the bit is not set yet */

        old_bit_value = ibuf_bitmap_page_get_bits(
                bitmap_page, page_no, zip_size,
                IBUF_BITMAP_BUFFERED, &bitmap_mtr);

        if (!old_bit_value) {
                ibuf_bitmap_page_set_bits(bitmap_page, page_no, zip_size,
                                          IBUF_BITMAP_BUFFERED, TRUE,
                                          &bitmap_mtr);
        }

        mtr_commit(&bitmap_mtr);

        cursor = btr_pcur_get_btr_cur(&pcur);

        if (mode == BTR_MODIFY_PREV) {
                err = btr_cur_optimistic_insert(BTR_NO_LOCKING_FLAG, cursor,
                                                ibuf_entry, &ins_rec,
                                                &dummy_big_rec, 0, thr, &mtr);
                if (err == DB_SUCCESS) {
                        /* Update the page max trx id field */
                        page_update_max_trx_id(btr_cur_get_block(cursor), NULL,
                                               thr_get_trx(thr)->id, &mtr);
                }
        } else {
                ut_ad(mode == BTR_MODIFY_TREE);

                /* We acquire an x-latch to the root page before the insert,
                because a pessimistic insert releases the tree x-latch,
                which would cause the x-latching of the root after that to
                break the latching order. */

                root = ibuf_tree_root_get(&mtr);

                err = btr_cur_optimistic_insert(
                        BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG,
                        cursor, ibuf_entry, &ins_rec,
                        &dummy_big_rec, 0, thr, &mtr);

                if (err == DB_FAIL) {
                        err = btr_cur_pessimistic_insert(
                                BTR_NO_LOCKING_FLAG
                                | BTR_NO_UNDO_LOG_FLAG,
                                cursor, ibuf_entry, &ins_rec,
                                &dummy_big_rec, 0, thr, &mtr);
                }

                if (err == DB_SUCCESS) {
                        /* Update the page max trx id field */
                        page_update_max_trx_id(btr_cur_get_block(cursor), NULL,
                                               thr_get_trx(thr)->id, &mtr);
                }

                ibuf_size_update(root, &mtr);
        }

function_exit:
#ifdef UNIV_IBUF_COUNT_DEBUG
        if (err == DB_SUCCESS) {
                fprintf(stderr,
                        "Incrementing ibuf count of space %lu page %lu\n"
                        "from %lu by 1\n", space, page_no,
                        ibuf_count_get(space, page_no));

                ibuf_count_set(space, page_no,
                               ibuf_count_get(space, page_no) + 1);
        }
#endif
        if (mode == BTR_MODIFY_TREE) {

                mutex_exit(&ibuf_mutex);
                mutex_exit(&ibuf_pessimistic_insert_mutex);
        }

        mtr_commit(&mtr);
        btr_pcur_close(&pcur);
        ibuf_exit();

        mem_heap_free(heap);

        if (err == DB_SUCCESS) {
                mutex_enter(&ibuf_mutex);

                ibuf->empty = FALSE;
                ibuf->n_inserts++;

                mutex_exit(&ibuf_mutex);

                if (mode == BTR_MODIFY_TREE) {
                        ibuf_contract_after_insert(entry_size);
                }
        }

        if (do_merge) {
#ifdef UNIV_IBUF_DEBUG
                ut_a(n_stored <= IBUF_MAX_N_PAGES_MERGED);
#endif
                buf_read_ibuf_merge_pages(FALSE, space_ids, space_versions,
                                          page_nos, n_stored);
        }

        return(err);
}

/*********************************************************************//**
Makes an index insert to the insert buffer, instead of directly to the disk
page, if this is possible. Does not do insert if the index is clustered
or unique.
@return TRUE if success */
UNIV_INTERN
ibool
ibuf_insert(
/*========*/
        const dtuple_t* entry,  /*!< in: index entry to insert */
        dict_index_t*   index,  /*!< in: index where to insert */
        ulint           space,  /*!< in: space id where to insert */
        ulint           zip_size,/*!< in: compressed page size in bytes, or 0 */
        ulint           page_no,/*!< in: page number where to insert */
        que_thr_t*      thr)    /*!< in: query thread */
{
        ulint   err;
        ulint   entry_size;

        ut_a(trx_sys_multiple_tablespace_format);
        ut_ad(dtuple_check_typed(entry));
        ut_ad(ut_is_2pow(zip_size));

        ut_a(!dict_index_is_clust(index));

        switch (UNIV_EXPECT(ibuf_use, IBUF_USE_INSERT)) {
        case IBUF_USE_NONE:
                return(FALSE);
        case IBUF_USE_INSERT:
                goto do_insert;
        case IBUF_USE_COUNT:
                break;
        }

        ut_error; /* unknown value of ibuf_use */

do_insert:
        entry_size = rec_get_converted_size(index, entry, 0);

        if (entry_size
            >= (page_get_free_space_of_empty(dict_table_is_comp(index->table))
                / 2)) {
                return(FALSE);
        }

        err = ibuf_insert_low(BTR_MODIFY_PREV, entry, entry_size,
                              index, space, zip_size, page_no, thr);
        if (err == DB_FAIL) {
                err = ibuf_insert_low(BTR_MODIFY_TREE, entry, entry_size,
                                      index, space, zip_size, page_no, thr);
        }

        if (err == DB_SUCCESS) {
#ifdef UNIV_IBUF_DEBUG
                /* fprintf(stderr, "Ibuf insert for page no %lu of index %s\n",
                page_no, index->name); */
#endif
                return(TRUE);

        } else {
                ut_a(err == DB_STRONG_FAIL);

                return(FALSE);
        }
}

/********************************************************************//**
During merge, inserts to an index page a secondary index entry extracted
from the insert buffer.
@return newly inserted record */
static
rec_t*
ibuf_insert_to_index_page_low(
/*==========================*/
                                /* out: newly inserted record */
        const dtuple_t* entry,  /*!< in: buffered entry to insert */
        buf_block_t*    block,  /*!< in/out: index page where the buffered
                                entry should be placed */
        dict_index_t*   index,  /*!< in: record descriptor */
        mtr_t*          mtr,    /*!< in/out: mtr */
        page_cur_t*     page_cur)/*!< in/out: cursor positioned on the record
                                after which to insert the buffered entry */
{
        const page_t*   page;
        ulint           space;
        ulint           page_no;
        ulint           zip_size;
        const page_t*   bitmap_page;
        ulint           old_bits;
        rec_t*          rec;
        DBUG_ENTER("ibuf_insert_to_index_page_low");

        rec = page_cur_tuple_insert(page_cur, entry, index, 0, mtr);
        if (rec != NULL) {
                DBUG_RETURN(rec);
        }

        /* If the record did not fit, reorganize */

        btr_page_reorganize(block, index, mtr);
        page_cur_search(block, index, entry, PAGE_CUR_LE, page_cur);

        /* This time the record must fit */

        rec = page_cur_tuple_insert(page_cur, entry, index, 0, mtr);
        if (rec != NULL) {
                DBUG_RETURN(rec);
        }

        page = buf_block_get_frame(block);

        ut_print_timestamp(stderr);

        fprintf(stderr,
                "  InnoDB: Error: Insert buffer insert fails;"
                " page free %lu, dtuple size %lu\n",
                (ulong) page_get_max_insert_size(page, 1),
                (ulong) rec_get_converted_size(index, entry, 0));
        fputs("InnoDB: Cannot insert index record ", stderr);
        dtuple_print(stderr, entry);
        fputs("\nInnoDB: The table where this index record belongs\n"
              "InnoDB: is now probably corrupt. Please run CHECK TABLE on\n"
              "InnoDB: that table.\n", stderr);

        space = page_get_space_id(page);
        zip_size = buf_block_get_zip_size(block);
        page_no = page_get_page_no(page);

        bitmap_page = ibuf_bitmap_get_map_page(space, page_no, zip_size, mtr);
        old_bits = ibuf_bitmap_page_get_bits(bitmap_page, page_no, zip_size,
                                             IBUF_BITMAP_FREE, mtr);

        fprintf(stderr,
                "InnoDB: space %lu, page %lu, zip_size %lu, bitmap bits %lu\n",
                (ulong) space, (ulong) page_no,
                (ulong) zip_size, (ulong) old_bits);

        fputs("InnoDB: Submit a detailed bug report"
              " to http://bugs.mysql.com\n", stderr);
        DBUG_RETURN(NULL);
}

/************************************************************************
During merge, inserts to an index page a secondary index entry extracted
from the insert buffer. */
static
void
ibuf_insert_to_index_page(
/*======================*/
        const dtuple_t* entry,  /*!< in: buffered entry to insert */
        buf_block_t*    block,  /*!< in/out: index page where the buffered entry
                                should be placed */
        dict_index_t*   index,  /*!< in: record descriptor */
        mtr_t*          mtr)    /*!< in: mtr */
{
        page_cur_t      page_cur;
        ulint           low_match;
        page_t*         page            = buf_block_get_frame(block);
        rec_t*          rec;
        DBUG_ENTER("ibuf_insert_to_index_page");

        ut_ad(ibuf_inside());
        ut_ad(dtuple_check_typed(entry));
        ut_ad(!buf_block_align(page)->index);

        if (UNIV_UNLIKELY(dict_table_is_comp(index->table)
                          != (ibool)!!page_is_comp(page))) {
                fputs("InnoDB: Trying to insert a record from"
                      " the insert buffer to an index page\n"
                      "InnoDB: but the 'compact' flag does not match!\n",
                      stderr);
                goto dump;
        }

        rec = page_rec_get_next(page_get_infimum_rec(page));

        if (UNIV_UNLIKELY(rec_get_n_fields(rec, index)
                          != dtuple_get_n_fields(entry))) {
                fputs("InnoDB: Trying to insert a record from"
                      " the insert buffer to an index page\n"
                      "InnoDB: but the number of fields does not match!\n",
                      stderr);
dump:
                buf_page_print(page, 0);

                dtuple_print(stderr, entry);

                fputs("InnoDB: The table where where"
                      " this index record belongs\n"
                      "InnoDB: is now probably corrupt."
                      " Please run CHECK TABLE on\n"
                      "InnoDB: your tables.\n"
                      "InnoDB: Submit a detailed bug report to"
                      " http://bugs.mysql.com!\n", stderr);

                DBUG_VOID_RETURN;
        }

        low_match = page_cur_search(block, index, entry,
                                    PAGE_CUR_LE, &page_cur);

        if (UNIV_UNLIKELY(low_match == dtuple_get_n_fields(entry))) {
                mem_heap_t*     heap;
                upd_t*          update;
                ulint*          offsets;
                page_zip_des_t* page_zip;

                rec = page_cur_get_rec(&page_cur);

                /* This is based on
                row_ins_sec_index_entry_by_modify(BTR_MODIFY_LEAF). */
                ut_ad(rec_get_deleted_flag(rec, page_is_comp(page)));

                heap = mem_heap_create(1024);

                offsets = rec_get_offsets(rec, index, NULL, ULINT_UNDEFINED,
                                          &heap);
                update = row_upd_build_sec_rec_difference_binary(
                        index, entry, rec, NULL, heap);

                page_zip = buf_block_get_page_zip(block);

                if (update->n_fields == 0) {
                        /* The records only differ in the delete-mark.
                        Clear the delete-mark, like we did before
                        Bug #56680 was fixed. */
                        btr_cur_set_deleted_flag_for_ibuf(
                                rec, page_zip, FALSE, mtr);
updated_in_place:
                        mem_heap_free(heap);
                        DBUG_VOID_RETURN;
                }

                /* Copy the info bits. Clear the delete-mark. */
                update->info_bits = rec_get_info_bits(rec, page_is_comp(page));
                update->info_bits &= ~REC_INFO_DELETED_FLAG;

                /* We cannot invoke btr_cur_optimistic_update() here,
                because we do not have a btr_cur_t or que_thr_t,
                as the insert buffer merge occurs at a very low level. */
                if (!row_upd_changes_field_size_or_external(index, offsets,
                                                            update)
                    && (!page_zip || btr_cur_update_alloc_zip(
                                page_zip, block, index,
                                rec_offs_size(offsets), FALSE, mtr))) {
                        /* This is the easy case. Do something similar
                        to btr_cur_update_in_place(). */
                        row_upd_rec_in_place(rec, index, offsets,
                                             update, page_zip);

                        /* Log the update in place operation. During recovery
                        MLOG_COMP_REC_UPDATE_IN_PLACE/MLOG_REC_UPDATE_IN_PLACE
                        expects trx_id, roll_ptr for secondary indexes. So we
                        just write dummy trx_id(0), roll_ptr(0) */
                        btr_cur_update_in_place_log(BTR_KEEP_SYS_FLAG, rec,
                                                    index, update,
                                                    NULL,
                                                    ut_dulint_zero, mtr);
                        DBUG_EXECUTE_IF(
                                "crash_after_log_ibuf_upd_inplace",
                                log_buffer_flush_to_disk();
                                fprintf(stderr,
                                        "InnoDB: Wrote log record for ibuf "
                                        "update in place operation\n");
                                DBUG_SUICIDE();
                        );

                        goto updated_in_place;
                }

                /* A collation may identify values that differ in
                storage length.
                Some examples (1 or 2 bytes):
                utf8_turkish_ci: I = U+0131 LATIN SMALL LETTER DOTLESS I
                utf8_general_ci: S = U+00DF LATIN SMALL LETTER SHARP S
                utf8_general_ci: A = U+00E4 LATIN SMALL LETTER A WITH DIAERESIS

                latin1_german2_ci: SS = U+00DF LATIN SMALL LETTER SHARP S

                Examples of a character (3-byte UTF-8 sequence)
                identified with 2 or 4 characters (1-byte UTF-8 sequences):

                utf8_unicode_ci: 'II' = U+2171 SMALL ROMAN NUMERAL TWO
                utf8_unicode_ci: '(10)' = U+247D PARENTHESIZED NUMBER TEN
                */

                /* Delete the different-length record, and insert the
                buffered one. */

                lock_rec_store_on_page_infimum(block, rec);
                page_cur_delete_rec(&page_cur, index, offsets, mtr);
                page_cur_move_to_prev(&page_cur);

                rec = ibuf_insert_to_index_page_low(entry, block, index, mtr,
                                                    &page_cur);
                ut_ad(!cmp_dtuple_rec(entry, rec,
                                      rec_get_offsets(rec, index, NULL,
                                                      ULINT_UNDEFINED,
                                                      &heap)));
                mem_heap_free(heap);

                lock_rec_restore_from_page_infimum(block, rec, block);
        } else {
                ibuf_insert_to_index_page_low(entry, block, index, mtr,
                                              &page_cur);
        }
        DBUG_VOID_RETURN;
}

/*********************************************************************//**
Deletes from ibuf the record on which pcur is positioned. If we have to
resort to a pessimistic delete, this function commits mtr and closes
the cursor.
@return TRUE if mtr was committed and pcur closed in this operation */
static
ibool
ibuf_delete_rec(
/*============*/
        ulint           space,  /*!< in: space id */
        ulint           page_no,/*!< in: index page number where the record
                                should belong */
        btr_pcur_t*     pcur,   /*!< in: pcur positioned on the record to
                                delete, having latch mode BTR_MODIFY_LEAF */
        const dtuple_t* search_tuple,
                                /*!< in: search tuple for entries of page_no */
        mtr_t*          mtr)    /*!< in: mtr */
{
        ibool           success;
        page_t*         root;
        ulint           err;

        ut_ad(ibuf_inside());
        ut_ad(page_rec_is_user_rec(btr_pcur_get_rec(pcur)));
        ut_ad(ibuf_rec_get_page_no(btr_pcur_get_rec(pcur)) == page_no);
        ut_ad(ibuf_rec_get_space(btr_pcur_get_rec(pcur)) == space);

#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
        if (ibuf_debug == 2) {
                /* Inject a fault (crash). We do this before trying
                optimistic delete, because a pessimistic delete in the
                change buffer would require a larger test case. */

                /* Flag the buffered record as processed, to avoid
                an assertion failure after crash recovery. */
                btr_cur_set_deleted_flag_for_ibuf(
                        btr_pcur_get_rec(pcur), NULL, TRUE, mtr);
                mtr_commit(mtr);
                log_make_checkpoint_at(IB_ULONGLONG_MAX, TRUE);
                DBUG_SUICIDE();
        }
#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */

        success = btr_cur_optimistic_delete(btr_pcur_get_btr_cur(pcur), mtr);

        if (success) {
#ifdef UNIV_IBUF_COUNT_DEBUG
                fprintf(stderr,
                        "Decrementing ibuf count of space %lu page %lu\n"
                        "from %lu by 1\n", space, page_no,
                        ibuf_count_get(space, page_no));
                ibuf_count_set(space, page_no,
                               ibuf_count_get(space, page_no) - 1);
#endif
                return(FALSE);
        }

        ut_ad(page_rec_is_user_rec(btr_pcur_get_rec(pcur)));
        ut_ad(ibuf_rec_get_page_no(btr_pcur_get_rec(pcur)) == page_no);
        ut_ad(ibuf_rec_get_space(btr_pcur_get_rec(pcur)) == space);

        /* We have to resort to a pessimistic delete from ibuf.
        Delete-mark the record so that it will not be applied again,
        in case the server crashes before the pessimistic delete is
        made persistent. */
        btr_cur_set_deleted_flag_for_ibuf(
                btr_pcur_get_rec(pcur), NULL, TRUE, mtr);

        btr_pcur_store_position(pcur, mtr);

        btr_pcur_commit_specify_mtr(pcur, mtr);

        mutex_enter(&ibuf_mutex);

        mtr_start(mtr);

        success = btr_pcur_restore_position(BTR_MODIFY_TREE, pcur, mtr);

        if (!success) {
                if (fil_space_get_flags(space) == ULINT_UNDEFINED) {
                        /* The tablespace has been dropped.  It is possible
                        that another thread has deleted the insert buffer
                        entry.  Do not complain. */
                        goto commit_and_exit;
                }

                fprintf(stderr,
                        "InnoDB: ERROR: Submit the output to"
                        " http://bugs.mysql.com\n"
                        "InnoDB: ibuf cursor restoration fails!\n"
                        "InnoDB: ibuf record inserted to page %lu\n",
                        (ulong) page_no);
                fflush(stderr);

                rec_print_old(stderr, btr_pcur_get_rec(pcur));
                rec_print_old(stderr, pcur->old_rec);
                dtuple_print(stderr, search_tuple);

                rec_print_old(stderr,
                              page_rec_get_next(btr_pcur_get_rec(pcur)));
                fflush(stderr);

                btr_pcur_commit_specify_mtr(pcur, mtr);

                fputs("InnoDB: Validating insert buffer tree:\n", stderr);
                if (!btr_validate_index(ibuf->index, NULL)) {
                        ut_error;
                }

                fprintf(stderr, "InnoDB: ibuf tree ok\n");
                fflush(stderr);

                goto func_exit;
        }

        root = ibuf_tree_root_get(mtr);

        btr_cur_pessimistic_delete(&err, TRUE, btr_pcur_get_btr_cur(pcur),
                                   RB_NONE, mtr);
        ut_a(err == DB_SUCCESS);

#ifdef UNIV_IBUF_COUNT_DEBUG
        ibuf_count_set(space, page_no, ibuf_count_get(space, page_no) - 1);
#endif
        ibuf_size_update(root, mtr);

commit_and_exit:
        btr_pcur_commit_specify_mtr(pcur, mtr);

func_exit:
        btr_pcur_close(pcur);

        mutex_exit(&ibuf_mutex);

        return(TRUE);
}

/*********************************************************************//**
When an index page is read from a disk to the buffer pool, this function
inserts to the page the possible index entries buffered in the insert buffer.
The entries are deleted from the insert buffer. If the page is not read, but
created in the buffer pool, this function deletes its buffered entries from
the insert buffer; there can exist entries for such a page if the page
belonged to an index which subsequently was dropped. */
UNIV_INTERN
void
ibuf_merge_or_delete_for_page(
/*==========================*/
        buf_block_t*    block,  /*!< in: if page has been read from
                                disk, pointer to the page x-latched,
                                else NULL */
        ulint           space,  /*!< in: space id of the index page */
        ulint           page_no,/*!< in: page number of the index page */
        ulint           zip_size,/*!< in: compressed page size in bytes,
                                or 0 */
        ibool           update_ibuf_bitmap)/*!< in: normally this is set
                                to TRUE, but if we have deleted or are
                                deleting the tablespace, then we
                                naturally do not want to update a
                                non-existent bitmap page */
{
        mem_heap_t*     heap;
        btr_pcur_t      pcur;
        dtuple_t*       search_tuple;
        ulint           n_inserts;
#ifdef UNIV_IBUF_DEBUG
        ulint           volume;
#endif
        page_zip_des_t* page_zip                = NULL;
        ibool           tablespace_being_deleted = FALSE;
        ibool           corruption_noticed      = FALSE;
        mtr_t           mtr;

        ut_ad(!block || buf_block_get_space(block) == space);
        ut_ad(!block || buf_block_get_page_no(block) == page_no);
        ut_ad(!block || buf_block_get_zip_size(block) == zip_size);
        ut_ad(!block || buf_block_get_io_fix(block) == BUF_IO_READ);

        if (srv_force_recovery >= SRV_FORCE_NO_IBUF_MERGE
            || trx_sys_hdr_page(space, page_no)) {
                return;
        }

        /* We cannot refer to zip_size in the following, because
        zip_size is passed as ULINT_UNDEFINED (it is unknown) when
        buf_read_ibuf_merge_pages() is merging (discarding) changes
        for a dropped tablespace.  When block != NULL or
        update_ibuf_bitmap is specified, the zip_size must be known.
        That is why we will repeat the check below, with zip_size in
        place of 0.  Passing zip_size as 0 assumes that the
        uncompressed page size always is a power-of-2 multiple of the
        compressed page size. */

        if (ibuf_fixed_addr_page(space, 0, page_no)
            || fsp_descr_page(0, page_no)) {
                return;
        }

        if (UNIV_LIKELY(update_ibuf_bitmap)) {
                ut_a(ut_is_2pow(zip_size));

                if (ibuf_fixed_addr_page(space, zip_size, page_no)
                    || fsp_descr_page(zip_size, page_no)) {
                        return;
                }

                /* If the following returns FALSE, we get the counter
                incremented, and must decrement it when we leave this
                function. When the counter is > 0, that prevents tablespace
                from being dropped. */

                tablespace_being_deleted = fil_inc_pending_ops(space);

                if (UNIV_UNLIKELY(tablespace_being_deleted)) {
                        /* Do not try to read the bitmap page from space;
                        just delete the ibuf records for the page */

                        block = NULL;
                        update_ibuf_bitmap = FALSE;
                } else {
                        page_t* bitmap_page;

                        mtr_start(&mtr);

                        bitmap_page = ibuf_bitmap_get_map_page(
                                space, page_no, zip_size, &mtr);

                        if (!ibuf_bitmap_page_get_bits(bitmap_page, page_no,
                                                       zip_size,
                                                       IBUF_BITMAP_BUFFERED,
                                                       &mtr)) {
                                /* No inserts buffered for this page */
                                mtr_commit(&mtr);

                                if (!tablespace_being_deleted) {
                                        fil_decr_pending_ops(space);
                                }

                                return;
                        }
                        mtr_commit(&mtr);
                }
        } else if (block
                   && (ibuf_fixed_addr_page(space, zip_size, page_no)
                      || fsp_descr_page(zip_size, page_no))) {

                return;
        }

        ibuf_enter();

        heap = mem_heap_create(512);

        if (!trx_sys_multiple_tablespace_format) {
                ut_a(trx_doublewrite_must_reset_space_ids);
                search_tuple = ibuf_search_tuple_build(space, page_no, heap);
        } else {
                search_tuple = ibuf_new_search_tuple_build(space, page_no,
                                                           heap);
        }

        if (block) {
                /* Move the ownership of the x-latch on the page to this OS
                thread, so that we can acquire a second x-latch on it. This
                is needed for the insert operations to the index page to pass
                the debug checks. */

                rw_lock_x_lock_move_ownership(&(block->lock));
                page_zip = buf_block_get_page_zip(block);

                if (UNIV_UNLIKELY(fil_page_get_type(block->frame)
                                  != FIL_PAGE_INDEX)
                    || UNIV_UNLIKELY(!page_is_leaf(block->frame))) {

                        page_t* bitmap_page;

                        corruption_noticed = TRUE;

                        ut_print_timestamp(stderr);

                        mtr_start(&mtr);

                        fputs("  InnoDB: Dump of the ibuf bitmap page:\n",
                              stderr);

                        bitmap_page = ibuf_bitmap_get_map_page(space, page_no,
                                                               zip_size, &mtr);
                        buf_page_print(bitmap_page, 0);

                        mtr_commit(&mtr);

                        fputs("\nInnoDB: Dump of the page:\n", stderr);

                        buf_page_print(block->frame, 0);

                        fprintf(stderr,
                                "InnoDB: Error: corruption in the tablespace."
                                " Bitmap shows insert\n"
                                "InnoDB: buffer records to page n:o %lu"
                                " though the page\n"
                                "InnoDB: type is %lu, which is"
                                " not an index leaf page!\n"
                                "InnoDB: We try to resolve the problem"
                                " by skipping the insert buffer\n"
                                "InnoDB: merge for this page."
                                " Please run CHECK TABLE on your tables\n"
                                "InnoDB: to determine if they are corrupt"
                                " after this.\n\n"
                                "InnoDB: Please submit a detailed bug report"
                                " to http://bugs.mysql.com\n\n",
                                (ulong) page_no,
                                (ulong)
                                fil_page_get_type(block->frame));
                }
        }

        n_inserts = 0;
#ifdef UNIV_IBUF_DEBUG
        volume = 0;
#endif
loop:
        mtr_start(&mtr);

        if (block) {
                ibool success;

                success = buf_page_get_known_nowait(
                        RW_X_LATCH, block,
                        BUF_KEEP_OLD, __FILE__, __LINE__, &mtr);

                ut_a(success);

                /* This is a user page (secondary index leaf page),
                but we pretend that it is a change buffer page in
                order to obey the latching order. This should be OK,
                because buffered changes are applied immediately while
                the block is io-fixed. Other threads must not try to
                latch an io-fixed block. */
                buf_block_dbg_add_level(block, SYNC_IBUF_TREE_NODE);
        }

        /* Position pcur in the insert buffer at the first entry for this
        index page */
        btr_pcur_open_on_user_rec(
                ibuf->index, search_tuple, PAGE_CUR_GE, BTR_MODIFY_LEAF,
                &pcur, &mtr);

        if (!btr_pcur_is_on_user_rec(&pcur)) {
                ut_ad(btr_pcur_is_after_last_in_tree(&pcur, &mtr));

                goto reset_bit;
        }

        for (;;) {
                rec_t*  rec;

                ut_ad(btr_pcur_is_on_user_rec(&pcur));

                rec = btr_pcur_get_rec(&pcur);

                /* Check if the entry is for this index page */
                if (ibuf_rec_get_page_no(rec) != page_no
                    || ibuf_rec_get_space(rec) != space) {

                        if (block) {
                                page_header_reset_last_insert(
                                        block->frame, page_zip, &mtr);
                        }

                        goto reset_bit;
                }

                if (UNIV_UNLIKELY(corruption_noticed)) {
                        fputs("InnoDB: Discarding record\n ", stderr);
                        rec_print_old(stderr, rec);
                        fputs("\nInnoDB: from the insert buffer!\n\n", stderr);
                } else if (block && !rec_get_deleted_flag(rec, 0)) {
                        /* Now we have at pcur a record which should be
                        inserted to the index page; NOTE that the call below
                        copies pointers to fields in rec, and we must
                        keep the latch to the rec page until the
                        insertion is finished! */
                        dtuple_t*       entry;
                        trx_id_t        max_trx_id;
                        dict_index_t*   dummy_index;

                        max_trx_id = page_get_max_trx_id(page_align(rec));
                        page_update_max_trx_id(block, page_zip, max_trx_id,
                                               &mtr);

                        entry = ibuf_build_entry_from_ibuf_rec(
                                rec, heap, &dummy_index);
#ifdef UNIV_IBUF_DEBUG
                        volume += rec_get_converted_size(dummy_index, entry, 0)
                                + page_dir_calc_reserved_space(1);
                        ut_a(volume <= 4 * UNIV_PAGE_SIZE
                             / IBUF_PAGE_SIZE_PER_FREE_SPACE);
#endif
                        ibuf_insert_to_index_page(entry, block,
                                                  dummy_index, &mtr);
                        ibuf_dummy_index_free(dummy_index);
                }

                n_inserts++;

                /* Delete the record from ibuf */
                if (ibuf_delete_rec(space, page_no, &pcur, search_tuple,
                                    &mtr)) {
                        /* Deletion was pessimistic and mtr was committed:
                        we start from the beginning again */

                        goto loop;
                } else if (btr_pcur_is_after_last_on_page(&pcur)) {
                        mtr_commit(&mtr);
                        btr_pcur_close(&pcur);

                        goto loop;
                }
        }

reset_bit:
#ifdef UNIV_IBUF_COUNT_DEBUG
        if (ibuf_count_get(space, page_no) > 0) {
                /* btr_print_tree(ibuf_data->index->tree, 100);
                ibuf_print(); */
        }
#endif
        if (UNIV_LIKELY(update_ibuf_bitmap)) {
                page_t* bitmap_page;

                bitmap_page = ibuf_bitmap_get_map_page(
                        space, page_no, zip_size, &mtr);

                ibuf_bitmap_page_set_bits(
                        bitmap_page, page_no, zip_size,
                        IBUF_BITMAP_BUFFERED, FALSE, &mtr);

                if (block) {
                        ulint old_bits = ibuf_bitmap_page_get_bits(
                                bitmap_page, page_no, zip_size,
                                IBUF_BITMAP_FREE, &mtr);

                        ulint new_bits = ibuf_index_page_calc_free(
                                zip_size, block);

                        if (old_bits != new_bits) {
                                ibuf_bitmap_page_set_bits(
                                        bitmap_page, page_no, zip_size,
                                        IBUF_BITMAP_FREE, new_bits, &mtr);
                        }
                }
        }

        mtr_commit(&mtr);
        btr_pcur_close(&pcur);
        mem_heap_free(heap);

        /* Protect our statistics keeping from race conditions */
        mutex_enter(&ibuf_mutex);

        ibuf->n_merges++;
        ibuf->n_merged_recs += n_inserts;

        mutex_exit(&ibuf_mutex);

        if (update_ibuf_bitmap && !tablespace_being_deleted) {

                fil_decr_pending_ops(space);
        }

        ibuf_exit();

#ifdef UNIV_IBUF_COUNT_DEBUG
        ut_a(ibuf_count_get(space, page_no) == 0);
#endif
}

/*********************************************************************//**
Deletes all entries in the insert buffer for a given space id. This is used
in DISCARD TABLESPACE and IMPORT TABLESPACE.
NOTE: this does not update the page free bitmaps in the space. The space will
become CORRUPT when you call this function! */
UNIV_INTERN
void
ibuf_delete_for_discarded_space(
/*============================*/
        ulint   space)  /*!< in: space id */
{
        mem_heap_t*     heap;
        btr_pcur_t      pcur;
        dtuple_t*       search_tuple;
        rec_t*          ibuf_rec;
        ulint           page_no;
        ibool           closed;
        ulint           n_inserts;
        mtr_t           mtr;

        heap = mem_heap_create(512);

        /* Use page number 0 to build the search tuple so that we get the
        cursor positioned at the first entry for this space id */

        search_tuple = ibuf_new_search_tuple_build(space, 0, heap);

        n_inserts = 0;
loop:
        ibuf_enter();

        mtr_start(&mtr);

        /* Position pcur in the insert buffer at the first entry for the
        space */
        btr_pcur_open_on_user_rec(
                ibuf->index, search_tuple, PAGE_CUR_GE, BTR_MODIFY_LEAF,
                &pcur, &mtr);

        if (!btr_pcur_is_on_user_rec(&pcur)) {
                ut_ad(btr_pcur_is_after_last_in_tree(&pcur, &mtr));

                goto leave_loop;
        }

        for (;;) {
                ut_ad(btr_pcur_is_on_user_rec(&pcur));

                ibuf_rec = btr_pcur_get_rec(&pcur);

                /* Check if the entry is for this space */
                if (ibuf_rec_get_space(ibuf_rec) != space) {

                        goto leave_loop;
                }

                page_no = ibuf_rec_get_page_no(ibuf_rec);

                n_inserts++;

                /* Delete the record from ibuf */
                closed = ibuf_delete_rec(space, page_no, &pcur, search_tuple,
                                         &mtr);
                if (closed) {
                        /* Deletion was pessimistic and mtr was committed:
                        we start from the beginning again */

                        ibuf_exit();

                        goto loop;
                }

                if (btr_pcur_is_after_last_on_page(&pcur)) {
                        mtr_commit(&mtr);
                        btr_pcur_close(&pcur);

                        ibuf_exit();

                        goto loop;
                }
        }

leave_loop:
        mtr_commit(&mtr);
        btr_pcur_close(&pcur);

        /* Protect our statistics keeping from race conditions */
        mutex_enter(&ibuf_mutex);

        ibuf->n_merges++;
        ibuf->n_merged_recs += n_inserts;

        mutex_exit(&ibuf_mutex);

        ibuf_exit();

        mem_heap_free(heap);
}

/******************************************************************//**
Looks if the insert buffer is empty.
@return TRUE if empty */
UNIV_INTERN
ibool
ibuf_is_empty(void)
/*===============*/
{
        ibool           is_empty;
        const page_t*   root;
        mtr_t           mtr;

        ibuf_enter();

        mutex_enter(&ibuf_mutex);

        mtr_start(&mtr);

        root = ibuf_tree_root_get(&mtr);

        if (page_get_n_recs(root) == 0) {

                is_empty = TRUE;

                if (ibuf->empty == FALSE) {
                        fprintf(stderr,
                                "InnoDB: Warning: insert buffer tree is empty"
                                " but the data struct does not\n"
                                "InnoDB: know it. This condition is legal"
                                " if the master thread has not yet\n"
                                "InnoDB: run to completion.\n");
                }
        } else {
                ut_a(ibuf->empty == FALSE);

                is_empty = FALSE;
        }

        mtr_commit(&mtr);

        mutex_exit(&ibuf_mutex);

        ibuf_exit();

        return(is_empty);
}

/******************************************************************//**
Prints info of ibuf. */
UNIV_INTERN
void
ibuf_print(
/*=======*/
        FILE*   file)   /*!< in: file where to print */
{
#ifdef UNIV_IBUF_COUNT_DEBUG
        ulint           i;
        ulint           j;
#endif

        mutex_enter(&ibuf_mutex);

        fprintf(file,
                "Ibuf: size %lu, free list len %lu, seg size %lu,\n"
                "%lu inserts, %lu merged recs, %lu merges\n",
                (ulong) ibuf->size,
                (ulong) ibuf->free_list_len,
                (ulong) ibuf->seg_size,
                (ulong) ibuf->n_inserts,
                (ulong) ibuf->n_merged_recs,
                (ulong) ibuf->n_merges);
#ifdef UNIV_IBUF_COUNT_DEBUG
        for (i = 0; i < IBUF_COUNT_N_SPACES; i++) {
                for (j = 0; j < IBUF_COUNT_N_PAGES; j++) {
                        ulint   count = ibuf_count_get(i, j);

                        if (count > 0) {
                                fprintf(stderr,
                                        "Ibuf count for space/page %lu/%lu"
                                        " is %lu\n",
                                        (ulong) i, (ulong) j, (ulong) count);
                        }
                }
        }
#endif /* UNIV_IBUF_COUNT_DEBUG */

        mutex_exit(&ibuf_mutex);
}
#endif /* !UNIV_HOTBACKUP */