Update autovacuum to use reloptions instead of a system catalog, for

[PostgreSQL.git] / src / backend / access / common / reloptions.c

/*-------------------------------------------------------------------------
 *
 * reloptions.c
 *        Core support for relation options (pg_class.reloptions)
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *        $PostgreSQL$
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/gist_private.h"
#include "access/hash.h"
#include "access/nbtree.h"
#include "access/reloptions.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "nodes/makefuncs.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/rel.h"

/*
 * Contents of pg_class.reloptions
 *
 * To add an option:
 *
 * (i) decide on a type (integer, real, bool, string), name, default value,
 * upper and lower bounds (if applicable); for strings, consider a validation
 * routine.
 * (ii) add a record below (or use add_<type>_reloption).
 * (iii) add it to the appropriate options struct (perhaps StdRdOptions)
 * (iv) add it to the appropriate handling routine (perhaps
 * default_reloptions)
 * (v) don't forget to document the option
 *
 * Note that we don't handle "oids" in relOpts because it is handled by
 * interpretOidsOption().
 */

static relopt_bool boolRelOpts[] =
{
        {
                {
                        "autovacuum_enabled",
                        "Enables autovacuum in this relation",
                        RELOPT_KIND_HEAP
                },
                true
        },
        /* list terminator */
        { { NULL } }
};

static relopt_int intRelOpts[] =
{
        {
                {
                        "fillfactor",
                        "Packs table pages only to this percentage",
                        RELOPT_KIND_HEAP
                },
                HEAP_DEFAULT_FILLFACTOR, HEAP_MIN_FILLFACTOR, 100
        },
        {
                {
                        "fillfactor",
                        "Packs btree index pages only to this percentage",
                        RELOPT_KIND_BTREE
                },
                BTREE_DEFAULT_FILLFACTOR, BTREE_MIN_FILLFACTOR, 100
        },
        {
                {
                        "fillfactor",
                        "Packs hash index pages only to this percentage",
                        RELOPT_KIND_HASH
                },
                HASH_DEFAULT_FILLFACTOR, HASH_MIN_FILLFACTOR, 100
        },
        {
                {
                        "fillfactor",
                        "Packs gist index pages only to this percentage",
                        RELOPT_KIND_GIST
                },
                GIST_DEFAULT_FILLFACTOR, GIST_MIN_FILLFACTOR, 100
        },
        {
                {
                        "autovacuum_vacuum_threshold",
                        "Minimum number of tuple updates or deletes prior to vacuum",
                        RELOPT_KIND_HEAP
                },
                50, 0, INT_MAX
        },
        {
                {
                        "autovacuum_analyze_threshold",
                        "Minimum number of tuple inserts, updates or deletes prior to analyze",
                        RELOPT_KIND_HEAP
                },
                50, 0, INT_MAX
        },
        {
                {
                        "autovacuum_vacuum_cost_delay",
                        "Vacuum cost delay in milliseconds, for autovacuum",
                        RELOPT_KIND_HEAP
                },
                20, 0, 1000
        },
        {
                {
                        "autovacuum_vacuum_cost_limit",
                        "Vacuum cost amount available before napping, for autovacuum",
                        RELOPT_KIND_HEAP
                },
                200, 1, 10000
        },
        {
                {
                        "autovacuum_freeze_min_age",
                        "Minimum age at which VACUUM should freeze a table row, for autovacuum",
                        RELOPT_KIND_HEAP
                },
                100000000, 0, 1000000000
        },
        {
                {
                        "autovacuum_freeze_max_age",
                        "Age at which to autovacuum a table to prevent transaction ID wraparound",
                        RELOPT_KIND_HEAP
                },
                200000000, 100000000, 2000000000
        },
        {
                {
                        "autovacuum_freeze_table_age",
                        "Age at which VACUUM should perform a full table sweep to replace old Xid values with FrozenXID",
                        RELOPT_KIND_HEAP
                }, 150000000, 0, 2000000000
        },
        /* list terminator */
        { { NULL } }
};

static relopt_real realRelOpts[] =
{
        {
                {
                        "autovacuum_vacuum_scale_factor",
                        "Number of tuple updates or deletes prior to vacuum as a fraction of reltuples",
                        RELOPT_KIND_HEAP
                },
                0.2, 0.0, 100.0
        },
        {
                {
                        "autovacuum_analyze_scale_factor",
                        "Number of tuple inserts, updates or deletes prior to analyze as a fraction of reltuples",
                        RELOPT_KIND_HEAP
                },
                0.1, 0.0, 100.0
        },
        /* list terminator */
        { { NULL } }
};

static relopt_string stringRelOpts[] = 
{
        /* list terminator */
        { { NULL } }
};

static relopt_gen **relOpts = NULL;
static int last_assigned_kind = RELOPT_KIND_LAST_DEFAULT + 1;

static int              num_custom_options = 0;
static relopt_gen **custom_options = NULL;
static bool             need_initialization = true;

static void initialize_reloptions(void);
static void parse_one_reloption(relopt_value *option, char *text_str,
                                        int text_len, bool validate);

/*
 * initialize_reloptions
 *              initialization routine, must be called before parsing
 *
 * Initialize the relOpts array and fill each variable's type and name length.
 */
static void
initialize_reloptions(void)
{
        int             i;
        int             j = 0;

        for (i = 0; boolRelOpts[i].gen.name; i++)
                j++;
        for (i = 0; intRelOpts[i].gen.name; i++)
                j++;
        for (i = 0; realRelOpts[i].gen.name; i++)
                j++;
        for (i = 0; stringRelOpts[i].gen.name; i++)
                j++;
        j += num_custom_options;

        if (relOpts)
                pfree(relOpts);
        relOpts = MemoryContextAlloc(TopMemoryContext,
                                                                 (j + 1) * sizeof(relopt_gen *));

        j = 0;
        for (i = 0; boolRelOpts[i].gen.name; i++)
        {
                relOpts[j] = &boolRelOpts[i].gen;
                relOpts[j]->type = RELOPT_TYPE_BOOL;
                relOpts[j]->namelen = strlen(relOpts[j]->name);
                j++;
        }

        for (i = 0; intRelOpts[i].gen.name; i++)
        {
                relOpts[j] = &intRelOpts[i].gen;
                relOpts[j]->type = RELOPT_TYPE_INT;
                relOpts[j]->namelen = strlen(relOpts[j]->name);
                j++;
        }

        for (i = 0; realRelOpts[i].gen.name; i++)
        {
                relOpts[j] = &realRelOpts[i].gen;
                relOpts[j]->type = RELOPT_TYPE_REAL;
                relOpts[j]->namelen = strlen(relOpts[j]->name);
                j++;
        }

        for (i = 0; stringRelOpts[i].gen.name; i++)
        {
                relOpts[j] = &stringRelOpts[i].gen;
                relOpts[j]->type = RELOPT_TYPE_STRING;
                relOpts[j]->namelen = strlen(relOpts[j]->name);
                j++;
        }

        for (i = 0; i < num_custom_options; i++)
        {
                relOpts[j] = custom_options[i];
                j++;
        }

        /* add a list terminator */
        relOpts[j] = NULL;
}

/*
 * add_reloption_kind
 *              Create a new relopt_kind value, to be used in custom reloptions by
 *              user-defined AMs.
 */
int
add_reloption_kind(void)
{
        if (last_assigned_kind >= RELOPT_KIND_MAX)
                ereport(ERROR,
                                (errmsg("user-defined relation parameter types limit exceeded")));

        return last_assigned_kind++;
}

/*
 * add_reloption
 *              Add an already-created custom reloption to the list, and recompute the
 *              main parser table.
 */
static void
add_reloption(relopt_gen *newoption)
{
        static int              max_custom_options = 0;

        if (num_custom_options >= max_custom_options)
        {
                MemoryContext   oldcxt;

                oldcxt = MemoryContextSwitchTo(TopMemoryContext);

                if (max_custom_options == 0)
                {
                        max_custom_options = 8;
                        custom_options = palloc(max_custom_options * sizeof(relopt_gen *));
                }
                else
                {
                        max_custom_options *= 2;
                        custom_options = repalloc(custom_options,
                                                                          max_custom_options * sizeof(relopt_gen *));
                }
                MemoryContextSwitchTo(oldcxt);
        }
        custom_options[num_custom_options++] = newoption;

        need_initialization = true;
}

/*
 * allocate_reloption
 *              Allocate a new reloption and initialize the type-agnostic fields
 *              (for types other than string)
 */
static relopt_gen *
allocate_reloption(int kind, int type, char *name, char *desc)
{
        MemoryContext   oldcxt;
        size_t                  size;
        relopt_gen         *newoption;

        Assert(type != RELOPT_TYPE_STRING);

        oldcxt = MemoryContextSwitchTo(TopMemoryContext);

        switch (type)
        {
                case RELOPT_TYPE_BOOL:
                        size = sizeof(relopt_bool);
                        break;
                case RELOPT_TYPE_INT:
                        size = sizeof(relopt_int);
                        break;
                case RELOPT_TYPE_REAL:
                        size = sizeof(relopt_real);
                        break;
                default:
                        elog(ERROR, "unsupported option type");
                        return NULL;    /* keep compiler quiet */
        }

        newoption = palloc(size);

        newoption->name = pstrdup(name);
        if (desc)
                newoption->desc = pstrdup(desc);
        else
                newoption->desc = NULL;
        newoption->kind = kind;
        newoption->namelen = strlen(name);
        newoption->type = type;

        MemoryContextSwitchTo(oldcxt);

        return newoption;
}

/*
 * add_bool_reloption
 *              Add a new boolean reloption
 */
void
add_bool_reloption(int kind, char *name, char *desc, bool default_val)
{
        relopt_bool        *newoption;

        newoption = (relopt_bool *) allocate_reloption(kind, RELOPT_TYPE_BOOL,
                                                                                                   name, desc);
        newoption->default_val = default_val;

        add_reloption((relopt_gen *) newoption);
}

/*
 * add_int_reloption
 *              Add a new integer reloption
 */
void
add_int_reloption(int kind, char *name, char *desc, int default_val,
                                  int min_val, int max_val)
{
        relopt_int         *newoption;

        newoption = (relopt_int *) allocate_reloption(kind, RELOPT_TYPE_INT,
                                                                                                  name, desc);
        newoption->default_val = default_val;
        newoption->min = min_val;
        newoption->max = max_val;

        add_reloption((relopt_gen *) newoption);
}

/*
 * add_real_reloption
 *              Add a new float reloption
 */
void
add_real_reloption(int kind, char *name, char *desc, double default_val,
                                  double min_val, double max_val)
{
        relopt_real        *newoption;

        newoption = (relopt_real *) allocate_reloption(kind, RELOPT_TYPE_REAL,
                                                                                                   name, desc);
        newoption->default_val = default_val;
        newoption->min = min_val;
        newoption->max = max_val;

        add_reloption((relopt_gen *) newoption);
}

/*
 * add_string_reloption
 *              Add a new string reloption
 *
 * "validator" is an optional function pointer that can be used to test the
 * validity of the values.  It must elog(ERROR) when the argument string is
 * not acceptable for the variable.  Note that the default value must pass
 * the validation.
 */
void
add_string_reloption(int kind, char *name, char *desc, char *default_val,
                                         validate_string_relopt validator)
{
        MemoryContext   oldcxt;
        relopt_string  *newoption;
        int                             default_len = 0;

        oldcxt = MemoryContextSwitchTo(TopMemoryContext);

        if (default_val)
                default_len = strlen(default_val);

        newoption = palloc0(sizeof(relopt_string) + default_len);

        newoption->gen.name = pstrdup(name);
        if (desc)
                newoption->gen.desc = pstrdup(desc);
        else
                newoption->gen.desc = NULL;
        newoption->gen.kind = kind;
        newoption->gen.namelen = strlen(name);
        newoption->gen.type = RELOPT_TYPE_STRING;
        newoption->validate_cb = validator;
        if (default_val)
        {
                strcpy(newoption->default_val, default_val);
                newoption->default_len = default_len;
                newoption->default_isnull = false;
        }
        else
        {
                newoption->default_val[0] = '\0';
                newoption->default_len = 0;
                newoption->default_isnull = true;
        }

        /* make sure the validator/default combination is sane */
        if (newoption->validate_cb)
                (newoption->validate_cb) (newoption->default_val);

        MemoryContextSwitchTo(oldcxt);

        add_reloption((relopt_gen *) newoption);
}

/*
 * Transform a relation options list (list of ReloptElem) into the text array
 * format that is kept in pg_class.reloptions, including only those options
 * that are in the passed namespace.  The output values do not include the
 * namespace.
 *
 * This is used for three cases: CREATE TABLE/INDEX, ALTER TABLE SET, and
 * ALTER TABLE RESET.  In the ALTER cases, oldOptions is the existing
 * reloptions value (possibly NULL), and we replace or remove entries
 * as needed.
 *
 * If ignoreOids is true, then we should ignore any occurrence of "oids"
 * in the list (it will be or has been handled by interpretOidsOption()).
 *
 * Note that this is not responsible for determining whether the options
 * are valid, but it does check that namespaces for all the options given are
 * listed in validnsps.  The NULL namespace is always valid and needs not be
 * explicitely listed.  Passing a NULL pointer means that only the NULL
 * namespace is valid.
 *
 * Both oldOptions and the result are text arrays (or NULL for "default"),
 * but we declare them as Datums to avoid including array.h in reloptions.h.
 */
Datum
transformRelOptions(Datum oldOptions, List *defList, char *namspace,
                                        char *validnsps[], bool ignoreOids, bool isReset)
{
        Datum           result;
        ArrayBuildState *astate;
        ListCell   *cell;

        /* no change if empty list */
        if (defList == NIL)
                return oldOptions;

        /* We build new array using accumArrayResult */
        astate = NULL;

        /* Copy any oldOptions that aren't to be replaced */
        if (PointerIsValid(DatumGetPointer(oldOptions)))
        {
                ArrayType  *array = DatumGetArrayTypeP(oldOptions);
                Datum      *oldoptions;
                int                     noldoptions;
                int                     i;

                Assert(ARR_ELEMTYPE(array) == TEXTOID);

                deconstruct_array(array, TEXTOID, -1, false, 'i',
                                                  &oldoptions, NULL, &noldoptions);

                for (i = 0; i < noldoptions; i++)
                {
                        text       *oldoption = DatumGetTextP(oldoptions[i]);
                        char       *text_str = VARDATA(oldoption);
                        int                     text_len = VARSIZE(oldoption) - VARHDRSZ;

                        /* Search for a match in defList */
                        foreach(cell, defList)
                        {
                                ReloptElem *def = lfirst(cell);
                                int                     kw_len;

                                /* ignore if not in the same namespace */
                                if (namspace == NULL)
                                {
                                        if (def->nmspc != NULL)
                                                continue;
                                }
                                else if (def->nmspc == NULL)
                                        continue;
                                else if (pg_strcasecmp(def->nmspc, namspace) != 0)
                                        continue;

                                kw_len = strlen(def->optname);
                                if (text_len > kw_len && text_str[kw_len] == '=' &&
                                        pg_strncasecmp(text_str, def->optname, kw_len) == 0)
                                        break;
                        }
                        if (!cell)
                        {
                                /* No match, so keep old option */
                                astate = accumArrayResult(astate, oldoptions[i],
                                                                                  false, TEXTOID,
                                                                                  CurrentMemoryContext);
                        }
                }
        }

        /*
         * If CREATE/SET, add new options to array; if RESET, just check that the
         * user didn't say RESET (option=val).  (Must do this because the grammar
         * doesn't enforce it.)
         */
        foreach(cell, defList)
        {
                ReloptElem    *def = lfirst(cell);


                if (isReset)
                {
                        if (def->arg != NULL)
                                ereport(ERROR,
                                                (errcode(ERRCODE_SYNTAX_ERROR),
                                        errmsg("RESET must not include values for parameters")));
                }
                else
                {
                        text       *t;
                        const char *value;
                        Size            len;

                        /*
                         * Error out if the namespace is not valid.  A NULL namespace
                         * is always valid.
                         */
                        if (def->nmspc != NULL)
                        {
                                bool    valid = false;
                                int             i;

                                if (validnsps)
                                {
                                        for (i = 0; validnsps[i]; i++)
                                        {
                                                if (pg_strcasecmp(def->nmspc, validnsps[i]) == 0)
                                                {
                                                        valid = true;
                                                        break;
                                                }
                                        }
                                }

                                if (!valid)
                                        ereport(ERROR,
                                                        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                         errmsg("unrecognized parameter namespace \"%s\"",
                                                                        def->nmspc)));
                        }

                        if (ignoreOids && pg_strcasecmp(def->optname, "oids") == 0)
                                continue;

                        /* ignore if not in the same namespace */
                        if (namspace == NULL)
                        {
                                if (def->nmspc != NULL)
                                        continue;
                        }
                        else if (def->nmspc == NULL)
                                continue;
                        else if (pg_strcasecmp(def->nmspc, namspace) != 0)
                                continue;

                        /*
                         * Flatten the ReloptElem into a text string like "name=arg". If we
                         * have just "name", assume "name=true" is meant.  Note: the
                         * namespace is not output.
                         */
                        if (def->arg != NULL)
                                value = reloptGetString(def);
                        else
                                value = "true";
                        len = VARHDRSZ + strlen(def->optname) + 1 + strlen(value);
                        /* +1 leaves room for sprintf's trailing null */
                        t = (text *) palloc(len + 1);
                        SET_VARSIZE(t, len);
                        sprintf(VARDATA(t), "%s=%s", def->optname, value);

                        astate = accumArrayResult(astate, PointerGetDatum(t),
                                                                          false, TEXTOID,
                                                                          CurrentMemoryContext);
                }
        }

        if (astate)
                result = makeArrayResult(astate, CurrentMemoryContext);
        else
                result = (Datum) 0;

        return result;
}


/*
 * Convert the text-array format of reloptions into a List of DefElem.
 * This is the inverse of transformRelOptions().
 */
List *
untransformRelOptions(Datum options)
{
        List       *result = NIL;
        ArrayType  *array;
        Datum      *optiondatums;
        int                     noptions;
        int                     i;

        /* Nothing to do if no options */
        if (!PointerIsValid(DatumGetPointer(options)))
                return result;

        array = DatumGetArrayTypeP(options);

        Assert(ARR_ELEMTYPE(array) == TEXTOID);

        deconstruct_array(array, TEXTOID, -1, false, 'i',
                                          &optiondatums, NULL, &noptions);

        for (i = 0; i < noptions; i++)
        {
                char       *s;
                char       *p;
                Node       *val = NULL;

                s = TextDatumGetCString(optiondatums[i]);
                p = strchr(s, '=');
                if (p)
                {
                        *p++ = '\0';
                        val = (Node *) makeString(pstrdup(p));
                }
                result = lappend(result, makeDefElem(pstrdup(s), val));
        }

        return result;
}

/*
 * Extract and parse reloptions from a pg_class tuple.
 *
 * This is a low-level routine, expected to be used by relcache code and
 * callers that do not have a table's relcache entry (e.g. autovacuum).  For
 * other uses, consider grabbing the rd_options pointer from the relcache entry
 * instead.
 *
 * tupdesc is pg_class' tuple descriptor.  amoptions is the amoptions regproc
 * in the case of the tuple corresponding to an index, or InvalidOid otherwise.
 */
bytea *
extractRelOptions(HeapTuple tuple, TupleDesc tupdesc, Oid amoptions)
{
        bytea  *options;
        bool    isnull;
        Datum   datum;
        Form_pg_class   classForm;

        datum = fastgetattr(tuple,
                                                Anum_pg_class_reloptions,
                                                tupdesc,
                                                &isnull);
        if (isnull)
                return NULL;

        classForm = (Form_pg_class) GETSTRUCT(tuple);

        /* Parse into appropriate format; don't error out here */
        switch (classForm->relkind)
        {
                case RELKIND_RELATION:
                case RELKIND_TOASTVALUE:
                case RELKIND_UNCATALOGED:
                        options = heap_reloptions(classForm->relkind, datum, false);
                        break;
                case RELKIND_INDEX:
                        options = index_reloptions(amoptions, datum, false);
                        break;
                default:
                        Assert(false);          /* can't get here */
                        options = NULL;         /* keep compiler quiet */
                        break;
        }
        
        return options;
}

/*
 * Interpret reloptions that are given in text-array format.
 *
 * options is a reloption text array as constructed by transformRelOptions.
 * kind specifies the family of options to be processed.
 *
 * The return value is a relopt_value * array on which the options actually
 * set in the options array are marked with isset=true.  The length of this
 * array is returned in *numrelopts.  Options not set are also present in the
 * array; this is so that the caller can easily locate the default values.
 *
 * If there are no options of the given kind, numrelopts is set to 0 and NULL
 * is returned.
 *
 * Note: values of type int, bool and real are allocated as part of the
 * returned array.  Values of type string are allocated separately and must
 * be freed by the caller.
 */
relopt_value *
parseRelOptions(Datum options, bool validate, relopt_kind kind,
                                int *numrelopts)
{
        relopt_value *reloptions;
        int                     numoptions = 0;
        int                     i;
        int                     j;

        if (need_initialization)
                initialize_reloptions();

        /* Build a list of expected options, based on kind */

        for (i = 0; relOpts[i]; i++)
                if (relOpts[i]->kind == kind)
                        numoptions++;

        if (numoptions == 0)
        {
                *numrelopts = 0;
                return NULL;
        }

        reloptions = palloc(numoptions * sizeof(relopt_value));

        for (i = 0, j = 0; relOpts[i]; i++)
        {
                if (relOpts[i]->kind == kind)
                {
                        reloptions[j].gen = relOpts[i];
                        reloptions[j].isset = false;
                        j++;
                }
        }

        /* Done if no options */
        if (PointerIsValid(DatumGetPointer(options)))
        {
                ArrayType  *array;
                Datum      *optiondatums;
                int                     noptions;

                array = DatumGetArrayTypeP(options);

                Assert(ARR_ELEMTYPE(array) == TEXTOID);

                deconstruct_array(array, TEXTOID, -1, false, 'i',
                                                  &optiondatums, NULL, &noptions);

                for (i = 0; i < noptions; i++)
                {
                        text       *optiontext = DatumGetTextP(optiondatums[i]);
                        char       *text_str = VARDATA(optiontext);
                        int                     text_len = VARSIZE(optiontext) - VARHDRSZ;
                        int                     j;

                        /* Search for a match in reloptions */
                        for (j = 0; j < numoptions; j++)
                        {
                                int                     kw_len = reloptions[j].gen->namelen;

                                if (text_len > kw_len && text_str[kw_len] == '=' &&
                                        pg_strncasecmp(text_str, reloptions[j].gen->name,
                                                                   kw_len) == 0)
                                {
                                        parse_one_reloption(&reloptions[j], text_str, text_len,
                                                                                validate);
                                        break;
                                }
                        }

                        if (j >= numoptions && validate)
                        {
                                char       *s;
                                char       *p;

                                s = TextDatumGetCString(optiondatums[i]);
                                p = strchr(s, '=');
                                if (p)
                                        *p = '\0';
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("unrecognized parameter \"%s\"", s)));
                        }
                }
        }

        *numrelopts = numoptions;
        return reloptions;
}

/*
 * Subroutine for parseRelOptions, to parse and validate a single option's
 * value
 */
static void
parse_one_reloption(relopt_value *option, char *text_str, int text_len,
                                        bool validate)
{
        char       *value;
        int                     value_len;
        bool            parsed;
        bool            nofree = false;

        if (option->isset && validate)
                ereport(ERROR,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("parameter \"%s\" specified more than once",
                                                option->gen->name)));

        value_len = text_len - option->gen->namelen - 1;
        value = (char *) palloc(value_len + 1);
        memcpy(value, text_str + option->gen->namelen + 1, value_len);
        value[value_len] = '\0';

        switch (option->gen->type)
        {
                case RELOPT_TYPE_BOOL:
                        {
                                parsed = parse_bool(value, &option->values.bool_val);
                                if (validate && !parsed)
                                        ereport(ERROR,
                                                        (errmsg("invalid value for boolean option \"%s\": %s",
                                                                        option->gen->name, value)));
                        }
                        break;
                case RELOPT_TYPE_INT:
                        {
                                relopt_int      *optint = (relopt_int *) option->gen;

                                parsed = parse_int(value, &option->values.int_val, 0, NULL);
                                if (validate && !parsed)
                                        ereport(ERROR,
                                                        (errmsg("invalid value for integer option \"%s\": %s",
                                                                        option->gen->name, value)));
                                if (validate && (option->values.int_val < optint->min ||
                                                                 option->values.int_val > optint->max))
                                        ereport(ERROR,
                                                        (errmsg("value %s out of bounds for option \"%s\"",
                                                                        value, option->gen->name),
                                                         errdetail("Valid values are between \"%d\" and \"%d\".",
                                                                           optint->min, optint->max)));
                        }
                        break;
                case RELOPT_TYPE_REAL:
                        {
                                relopt_real     *optreal = (relopt_real *) option->gen;

                                parsed = parse_real(value, &option->values.real_val);
                                if (validate && !parsed)
                                        ereport(ERROR,
                                                        (errmsg("invalid value for floating point option \"%s\": %s",
                                                                        option->gen->name, value)));
                                if (validate && (option->values.real_val < optreal->min ||
                                                                 option->values.real_val > optreal->max))
                                        ereport(ERROR,
                                                        (errmsg("value %s out of bounds for option \"%s\"",
                                                                        value, option->gen->name),
                                                         errdetail("Valid values are between \"%f\" and \"%f\".",
                                                                           optreal->min, optreal->max)));
                        }
                        break;
                case RELOPT_TYPE_STRING:
                        {
                                relopt_string   *optstring = (relopt_string *) option->gen;

                                option->values.string_val = value;
                                nofree = true;
                                if (validate && optstring->validate_cb)
                                        (optstring->validate_cb) (value);
                                parsed = true;
                        }
                        break;
                default:
                        elog(ERROR, "unsupported reloption type %d", option->gen->type);
                        parsed = true; /* quiet compiler */
                        break;
        }

        if (parsed)
                option->isset = true;
        if (!nofree)
                pfree(value);
}

/*
 * Given the result from parseRelOptions, allocate a struct that's of the
 * specified base size plus any extra space that's needed for string variables.
 *
 * "base" should be sizeof(struct) of the reloptions struct (StdRdOptions or
 * equivalent).
 */
void *
allocateReloptStruct(Size base, relopt_value *options, int numoptions)
{
        Size    size = base;
        int             i;

        for (i = 0; i < numoptions; i++)
                if (options[i].gen->type == RELOPT_TYPE_STRING)
                        size += GET_STRING_RELOPTION_LEN(options[i]) + 1;

        return palloc0(size);
}

/*
 * Given the result of parseRelOptions and a parsing table, fill in the
 * struct (previously allocated with allocateReloptStruct) with the parsed
 * values.
 *
 * rdopts is the pointer to the allocated struct to be filled; basesize is
 * the sizeof(struct) that was passed to allocateReloptStruct.  options and
 * numoptions are parseRelOptions' output.  elems and numelems is the array
 * of elements to be parsed.  Note that when validate is true, it is expected
 * that all options are also in elems.
 */
void
fillRelOptions(void *rdopts, Size basesize, relopt_value *options,
                           int numoptions, bool validate, relopt_parse_elt *elems,
                           int numelems)
{
        int             i;
        int             offset = basesize;

        for (i = 0; i < numoptions; i++)
        {
                int             j;
                bool    found = false;

                for (j = 0; j < numelems; j++)
                {
                        if (pg_strcasecmp(options[i].gen->name, elems[j].optname) == 0)
                        {
                                relopt_string *optstring;
                                char   *itempos = ((char *) rdopts) + elems[j].offset;
                                char   *string_val;

                                switch (options[i].gen->type)
                                {
                                        case RELOPT_TYPE_BOOL:
                                                *(bool *) itempos = options[i].isset ?
                                                        options[i].values.bool_val :
                                                        ((relopt_bool *) options[i].gen)->default_val;
                                                break;
                                        case RELOPT_TYPE_INT:
                                                *(int *) itempos = options[i].isset ?
                                                        options[i].values.int_val :
                                                        ((relopt_int *) options[i].gen)->default_val;
                                                break;
                                        case RELOPT_TYPE_REAL:
                                                *(double *) itempos = options[i].isset ?
                                                        options[i].values.real_val :
                                                        ((relopt_real *) options[i].gen)->default_val;
                                                break;
                                        case RELOPT_TYPE_STRING:
                                                optstring = (relopt_string *) options[i].gen;
                                                if (options[i].isset)
                                                        string_val = options[i].values.string_val;
                                                else if (!optstring->default_isnull)
                                                        string_val = optstring->default_val;
                                                else
                                                        string_val = NULL;

                                                if (string_val == NULL)
                                                        *(int *) itempos = 0;
                                                else
                                                {
                                                        strcpy((char *) rdopts + offset, string_val);
                                                        *(int *) itempos = offset;
                                                        offset += strlen(string_val) + 1;
                                                }
                                                break;
                                        default:
                                                elog(ERROR, "unrecognized reloption type %c",
                                                         options[i].gen->type);
                                                break;
                                }
                                found = true;
                                break;
                        }
                }
                if (validate && !found)
                        elog(ERROR, "storate parameter \"%s\" not found in parse table",
                                 options[i].gen->name);
        }
        SET_VARSIZE(rdopts, offset);
}


/*
 * Option parser for anything that uses StdRdOptions (i.e. fillfactor and
 * autovacuum)
 */
bytea *
default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
{
        relopt_value   *options;
        StdRdOptions   *rdopts;
        int                             numoptions;
        relopt_parse_elt tab[] = {
                {"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
                {"autovacuum_enabled", RELOPT_TYPE_BOOL,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
                {"autovacuum_vacuum_threshold", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, vacuum_threshold)},
                {"autovacuum_analyze_threshold", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, analyze_threshold)},
                {"autovacuum_vacuum_cost_delay", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, vacuum_cost_delay)},
                {"autovacuum_vacuum_cost_limit", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, vacuum_cost_limit)},
                {"autovacuum_freeze_min_age", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, freeze_min_age)},
                {"autovacuum_freeze_max_age", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, freeze_max_age)},
                {"autovacuum_freeze_table_age", RELOPT_TYPE_INT,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, freeze_table_age)},
                {"autovacuum_vacuum_scale_factor", RELOPT_TYPE_REAL,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, vacuum_scale_factor)},
                {"autovacuum_analyze_scale_factor", RELOPT_TYPE_REAL,
                        offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, analyze_scale_factor)}
        };

        options = parseRelOptions(reloptions, validate, kind, &numoptions);

        /* if none set, we're done */
        if (numoptions == 0)
                return NULL;

        rdopts = allocateReloptStruct(sizeof(StdRdOptions), options, numoptions);

        fillRelOptions((void *) rdopts, sizeof(StdRdOptions), options, numoptions,
                                   validate, tab, lengthof(tab));

        pfree(options);

        return (bytea *) rdopts;
}

/*
 * Parse options for heaps and toast tables.
 */
bytea *
heap_reloptions(char relkind, Datum reloptions, bool validate)
{
        return default_reloptions(reloptions, validate, RELOPT_KIND_HEAP);
}


/*
 * Parse options for indexes.
 *
 *      amoptions       Oid of option parser
 *      reloptions      options as text[] datum
 *      validate        error flag
 */
bytea *
index_reloptions(RegProcedure amoptions, Datum reloptions, bool validate)
{
        FmgrInfo        flinfo;
        FunctionCallInfoData fcinfo;
        Datum           result;

        Assert(RegProcedureIsValid(amoptions));

        /* Assume function is strict */
        if (!PointerIsValid(DatumGetPointer(reloptions)))
                return NULL;

        /* Can't use OidFunctionCallN because we might get a NULL result */
        fmgr_info(amoptions, &flinfo);

        InitFunctionCallInfoData(fcinfo, &flinfo, 2, NULL, NULL);

        fcinfo.arg[0] = reloptions;
        fcinfo.arg[1] = BoolGetDatum(validate);
        fcinfo.argnull[0] = false;
        fcinfo.argnull[1] = false;

        result = FunctionCallInvoke(&fcinfo);

        if (fcinfo.isnull || DatumGetPointer(result) == NULL)
                return NULL;

        return DatumGetByteaP(result);
}