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1 '\" t
2 .\" Title: \fBndbmtd\fR
3 .\" Author: [FIXME: author] [see http://docbook.sf.net/el/author]
4 .\" Generator: DocBook XSL Stylesheets v1.77.1 <http://docbook.sf.net/>
5 .\" Date: 11/04/2013
6 .\" Manual: MySQL Database System
7 .\" Source: MySQL 5.1
8 .\" Language: English
9 .\"
10 .TH "\FBNDBMTD\FR" "8" "11/04/2013" "MySQL 5\&.1" "MySQL Database System"
11 .\" -----------------------------------------------------------------
12 .\" * Define some portability stuff
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15 .\" http://bugs.debian.org/507673
16 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
17 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
18 .ie \n(.g .ds Aq \(aq
19 .el .ds Aq '
20 .\" -----------------------------------------------------------------
21 .\" * set default formatting
22 .\" -----------------------------------------------------------------
23 .\" disable hyphenation
24 .nh
25 .\" disable justification (adjust text to left margin only)
26 .ad l
27 .\" -----------------------------------------------------------------
28 .\" * MAIN CONTENT STARTS HERE *
29 .\" -----------------------------------------------------------------
30 .\" ndbmtd
31 .\" MySQL Cluster: ndbmtd
32 .\" MySQL Cluster: data nodes
33 .\" data nodes (MySQL Cluster)
34 .\" storage nodes - see data nodes, ndbd, ndbmtd
35 .SH "NAME"
36 ndbmtd \- the MySQL Cluster data node daemon (multi\-threaded version)
37 .SH "SYNOPSIS"
38 .HP \w'\fBndbmtd\ \fR\fB\fIoptions\fR\fR\ 'u
39 \fBndbmtd \fR\fB\fIoptions\fR\fR
40 .SH "DESCRIPTION"
41 .PP
42 \fBndbmtd\fR
43 is a multi\-threaded version of
44 \fBndbd\fR, the process that is used to handle all the data in tables using the
45 NDBCLUSTER
46 storage engine\&.
47 \fBndbmtd\fR
48 is intended for use on host computers having multiple CPU cores\&. Except where otherwise noted,
49 \fBndbmtd\fR
50 functions in the same way as
51 \fBndbd\fR; therefore, in this section, we concentrate on the ways in which
52 \fBndbmtd\fR
53 differs from
54 \fBndbd\fR, and you should consult
55 \fBndbd\fR(8), for additional information about running MySQL Cluster data nodes that apply to both the single\-threaded and multi\-threaded versions of the data node process\&.
56 .PP
57 Command\-line options and configuration parameters used with
58 \fBndbd\fR
59 also apply to
60 \fBndbmtd\fR\&. For more information about these options and parameters, see
61 \fBndbd\fR(8), and
62 Section\ \&17.3.2.6, \(lqDefining MySQL Cluster Data Nodes\(rq, respectively\&.
63 .PP
64 \fBndbmtd\fR
65 is also file system\-compatible with
66 \fBndbd\fR\&. In other words, a data node running
67 \fBndbd\fR
68 can be stopped, the binary replaced with
69 \fBndbmtd\fR, and then restarted without any loss of data\&. (However, when doing this, you must make sure that
70 MaxNoOfExecutionThreads
71 is set to an apppriate value before restarting the node if you wish for
72 \fBndbmtd\fR
73 to run in multi\-threaded fashion\&.) Similarly, an
74 \fBndbmtd\fR
75 binary can be replaced with
76 \fBndbd\fR
77 simply by stopping the node and then starting
78 \fBndbd\fR
79 in place of the multi\-threaded binary\&. It is not necessary when switching between the two to start the data node binary using
80 \fB\-\-initial\fR\&.
81 .PP
82 Prior to MySQL Cluster NDB 7\&.0\&.6, there were known issues when using
83 \fBndbmtd\fR
84 with MySQL Cluster Disk Data tables\&. If you wish to use multi\-threaded data nodes with disk\-based
85 NDB
86 tables, you should ensure that you are running MySQL Cluster NDB 7\&.0\&.6 or later (see Bug #41915 and Bug #44915)
87 .PP
88 Using
89 \fBndbmtd\fR
90 differs from using
91 \fBndbd\fR
92 in two key respects:
93 .sp
94 .RS 4
95 .ie n \{\
96 \h'-04' 1.\h'+01'\c
97 .\}
98 .el \{\
99 .sp -1
100 .IP " 1." 4.2
101 .\}
102 Because
103 \fBndbmtd\fR
104 runs by default in single\-threaded mode (that is, it behaves like
105 \fBndbd\fR), you must configure it to use multiple threads\&. This can be done by setting an appropriate value in the
106 config\&.ini
107 file for the
108 MaxNoOfExecutionThreads
109 configuration parameter\&. For more information about this parameter and its use, see
110 Multi-Threading Configuration Parameters (ndbmtd)\&.
111 .RE
112 .sp
113 .RS 4
114 .ie n \{\
115 \h'-04' 2.\h'+01'\c
116 .\}
117 .el \{\
118 .sp -1
119 .IP " 2." 4.2
120 .\}
121 Trace files are generated by critical errors in
122 \fBndbmtd\fR
123 processes in a somewhat different fashion from how these are generated by
124 \fBndbd\fR
125 failures\&. These differences are discussed in more detail in the next few paragraphs\&.
126 .RE
127 .\" ndbmtd: trace files
128 .\" trace files: ndbmtd
129 .\" MySQL Cluster: log files
130 .\" log files (MySQL Cluster): ndbmtd
131 .\" ndbmtd: trace files
132 .PP
133 Like
134 \fBndbd\fR,
135 \fBndbmtd\fR
136 generates a set of log files which are placed in the directory specified by
137 DataDir
138 in the
139 config\&.ini
140 configuration file\&. Except for trace files, these are generated in the same way and have the same names as those generated by
141 \fBndbd\fR\&.
142 .PP
143 In the event of a critical error,
144 \fBndbmtd\fR
145 generates trace files describing what happened just prior to the error\*(Aq occurrence\&. These files, which can be found in the data node\*(Aqs
146 DataDir, are useful for analysis of problems by the MySQL Cluster Development and Support teams\&. One trace file is generated for each
147 \fBndbmtd\fR
148 thread\&. The names of these files have the following pattern:
149 .sp
150 .if n \{\
151 .RS 4
152 .\}
153 .nf
154 ndb_\fInode_id\fR_trace\&.log\&.\fItrace_id\fR_t\fIthread_id\fR,
155 .fi
156 .if n \{\
157 .RE
158 .\}
159 .PP
160 In this pattern,
161 \fInode_id\fR
162 stands for the data node\*(Aqs unique node ID in the cluster,
163 \fItrace_id\fR
164 is a trace sequence number, and
165 \fIthread_id\fR
166 is the thread ID\&. For example, in the event of the failure of an
167 \fBndbmtd\fR
168 process running as a MySQL Cluster data node having the node ID 3 and with
169 MaxNoOfExecutionThreads
170 equal to 4, four trace files are generated in the data node\*(Aqs data directory\&. If the is the first time this node has failed, then these files are named
171 ndb_3_trace\&.log\&.1_t1,
172 ndb_3_trace\&.log\&.1_t2,
173 ndb_3_trace\&.log\&.1_t3, and
174 ndb_3_trace\&.log\&.1_t4\&. Internally, these trace files follow the same format as
175 \fBndbd\fR
176 trace files\&.
177 .PP
178 The
179 \fBndbd\fR
180 exit codes and messages that are generated when a data node process shuts down prematurely are also used by
181 \fBndbmtd\fR\&. See
182 \m[blue]\fBndbd Error Messages\fR\m[]\&\s-2\u[1]\d\s+2, for a listing of these\&.
183 .if n \{\
184 .sp
185 .\}
186 .RS 4
187 .it 1 an-trap
188 .nr an-no-space-flag 1
189 .nr an-break-flag 1
190 .br
191 .ps +1
192 \fBNote\fR
193 .ps -1
194 .br
195 .PP
196 It is possible to use
197 \fBndbd\fR
198 and
199 \fBndbmtd\fR
200 concurrently on different data nodes in the same MySQL Cluster\&. However, such configurations have not been tested extensively; thus, we cannot recommend doing so in a production setting at this time\&.
201 .sp .5v
202 .RE
203 .SH "COPYRIGHT"
204 .br
205 .PP
206 Copyright \(co 1997, 2013, Oracle and/or its affiliates. All rights reserved.
207 .PP
208 This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
209 .PP
210 This documentation 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.
211 .PP
212 You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.
213 .sp
214 .SH "NOTES"
215 .IP " 1." 4
216 ndbd Error Messages
217 .RS 4
218 \%http://dev.mysql.com/doc/ndbapi/en/ndbd-error-messages.html
219 .RE
220 .SH "SEE ALSO"
221 For more information, please refer to the MySQL Reference Manual,
222 which may already be installed locally and which is also available
223 online at http://dev.mysql.com/doc/.
224 .SH AUTHOR
225 Oracle Corporation (http://dev.mysql.com/).