1INNOCHECKSUM(1) MySQL Database System INNOCHECKSUM(1)
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6 innochecksum - offline InnoDB file checksum utility
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9 innochecksum [options] file_name
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12 innochecksum prints checksums for InnoDB files. This tool reads an
13 InnoDB tablespace file, calculates the checksum for each page, compares
14 the calculated checksum to the stored checksum, and reports mismatches,
15 which indicate damaged pages. It was originally developed to speed up
16 verifying the integrity of tablespace files after power outages but can
17 also be used after file copies. Because checksum mismatches cause
18 InnoDB to deliberately shut down a running server, it may be preferable
19 to use this tool rather than waiting for an in-production server to
20 encounter the damaged pages.
21 innochecksum cannot be used on tablespace files that the server already
23 has open. For such files, you should use CHECK TABLE to check tables
24 within the tablespace. Attempting to run innochecksum on a tablespace
25 that the server already has open will result in an “Unable to lock
26 file” error.
27 If checksum mismatches are found, you would normally restore the
29 tablespace from backup or start the server and attempt to use mysqldump
30 to make a backup of the tables within the tablespace.
31 Invoke innochecksum like this:
33 shell> innochecksum [options] file_name
35 innochecksum Options
37 innochecksum supports the following options. For options that refer to
39 page numbers, the numbers are zero-based.
40 · --help, -?
42 Displays command line help. Example usage:
44 shell> innochecksum --help
46 · --info, -I
48 Synonym for --help. Displays command line help. Example usage:
50 shell> innochecksum --info
52 · --version, -V
54 Displays version information. Example usage:
56 shell> innochecksum --version
58 · --verbose, -v
60 Verbose mode; prints a progress indicator to the log file every
62 five seconds. In order for the progress indicator to be printed,
63 the log file must be specified using the --log option. To turn on
64 verbose mode, run:
65 shell> innochecksum --verbose
67 To turn off verbose mode, run:
69 shell> innochecksum --verbose=FALSE
71 The --verbose option and --log option can be specified at the same
73 time. For example:
74 shell> innochecksum --verbose --log=/var/lib/mysql/test/logtest.txt
76 To locate the progress indicator information in the log file, you
78 can perform the following search:
79 shell> cat ./logtest.txt | grep -i "okay"
81 The progress indicator information in the log file appears similar
83 to the following:
84 page 1663 okay: 2.863% done
86 page 8447 okay: 14.537% done
87 page 13695 okay: 23.568% done
88 page 18815 okay: 32.379% done
89 page 23039 okay: 39.648% done
90 page 28351 okay: 48.789% done
91 page 33023 okay: 56.828% done
92 page 37951 okay: 65.308% done
93 page 44095 okay: 75.881% done
94 page 49407 okay: 85.022% done
95 page 54463 okay: 93.722% done
96 ...
97 · --count, -c
99 Print a count of the number of pages in the file and exit. Example
101 usage:
102 shell> innochecksum --count ../data/test/tab1.ibd
104 · --start-page=num, -s num
106 Start at this page number. Example usage:
108 shell> innochecksum --start-page=600 ../data/test/tab1.ibd
110 or:
112 shell> innochecksum -s 600 ../data/test/tab1.ibd
114 · --end-page=num, -e num
116 End at this page number. Example usage:
118 shell> innochecksum --end-page=700 ../data/test/tab1.ibd
120 or:
122 shell> innochecksum --p 700 ../data/test/tab1.ibd
124 · --page=num, -p num
126 Check only this page number. Example usage:
128 shell> innochecksum --page=701 ../data/test/tab1.ibd
130 · --strict-check, -C
132 Specify a strict checksum algorithm. Options include innodb, crc32,
134 and none.
135 In this example, the innodb checksum algorithm is specified:
137 shell> innochecksum --strict-check=innodb ../data/test/tab1.ibd
139 In this example, the crc32 checksum algorithm is specified:
141 shell> innochecksum -C crc32 ../data/test/tab1.ibd
143 The following conditions apply:
145 · If you do not specify the --strict-check option, innochecksum
147 validates against innodb, crc32 and none.
148 · If you specify the none option, only checksums generated by
150 none are allowed.
151 · If you specify the innodb option, only checksums generated by
153 innodb are allowed.
154 · If you specify the crc32 option, only checksums generated by
156 crc32 are allowed.
157 · --no-check, -n
159 Ignore the checksum verification when rewriting a checksum. This
161 option may only be used with the innochecksum --write option. If
162 the --write option is not specified, innochecksum will terminate.
163 In this example, an innodb checksum is rewritten to replace an
165 invalid checksum:
166 shell> innochecksum --no-check --write innodb ../data/test/tab1.ibd
168 · --allow-mismatches, -a
170 The maximum number of checksum mismatches allowed before
172 innochecksum terminates. The default setting is 0. If
173 --allow-mismatches=N, where N>=0, N mismatches are permitted and
174 innochecksum terminates at N+1. When --allow-mismatches is set to
175 0, innochecksum terminates on the first checksum mismatch.
176 In this example, an existing innodb checksum is rewritten to set
178 --allow-mismatches to 1.
179 shell> innochecksum --allow-mismatches=1 --write innodb ../data/test/tab1.ibd
181 With --allow-mismatches set to 1, if there is a mismatch at page
183 600 and another at page 700 on a file with 1000 pages, the checksum
184 is updated for pages 0-599 and 601-699. Because --allow-mismatches
185 is set to 1, the checksum tolerates the first mismatch and
186 terminates on the second mismatch, leaving page 600 and pages
187 700-999 unchanged.
188 · --write=name, -w num
190 Rewrite a checksum. When rewriting an invalid checksum, the
192 --no-check option must be used together with the --write option.
193 The --no-check option tells innochecksum to ignore verification of
194 the invalid checksum. You do not have to specify the --no-check
195 option if the current checksum is valid.
196 An algorithm must be specified when using the --write option.
198 Possible values for the --write option are:
199 · innodb: A checksum calculated in software, using the original
201 algorithm from InnoDB.
202 · crc32: A checksum calculated using the crc32 algorithm,
204 possibly done with a hardware assist.
205 · none: A constant number.
207 The --write option rewrites entire pages to disk. If the new
209 checksum is identical to the existing checksum, the new checksum is
210 not written to disk in order to minimize I/O.
211 innochecksum obtains an exclusive lock when the --write option is
213 used.
214 In this example, a crc32 checksum is written for tab1.ibd:
216 shell> innochecksum -w crc32 ../data/test/tab1.ibd
218 In this example, a crc32 checksum is rewritten to replace an
220 invalid crc32 checksum:
221 shell> innochecksum --no-check --write crc32 ../data/test/tab1.ibd
223 · --page-type-summary, -S
225 Display a count of each page type in a tablespace. Example usage:
227 shell> innochecksum --page-type-summary ../data/test/tab1.ibd
229 Sample output for --page-type-summary:
231 File::../data/test/tab1.ibd
233 ================PAGE TYPE SUMMARY==============
234 #PAGE_COUNT PAGE_TYPE
235 ===============================================
236 2 Index page
237 0 Undo log page
238 1 Inode page
239 0 Insert buffer free list page
240 2 Freshly allocated page
241 1 Insert buffer bitmap
242 0 System page
243 0 Transaction system page
244 1 File Space Header
245 0 Extent descriptor page
246 0 BLOB page
247 0 Compressed BLOB page
248 0 Other type of page
249 ===============================================
250 Additional information:
251 Undo page type: 0 insert, 0 update, 0 other
252 Undo page state: 0 active, 0 cached, 0 to_free, 0 to_purge, 0 prepared, 0 other
253 · --page-type-dump, -D
255 Dump the page type information for each page in a tablespace to
257 stderr or stdout. Example usage:
258 shell> innochecksum --page-type-dump=/tmp/a.txt ../data/test/tab1.ibd
260 · --log, -l
262 Log output for the innochecksum tool. A log file name must be
264 provided. Log output contains checksum values for each tablespace
265 page. For uncompressed tables, LSN values are also provided. The
266 --log replaces the --debug option, which was available in earlier
267 releases. Example usage:
268 shell> innochecksum --log=/tmp/log.txt ../data/test/tab1.ibd
270 or:
272 shell> innochecksum -l /tmp/log.txt ../data/test/tab1.ibd
274 · - option.
276 Specify the - option to read from standard input. If the - option
278 is missing when “read from standard in” is expected, innochecksum
279 will output innochecksum usage information indicating that the “-”
280 option was omitted. Example usages:
281 shell> cat t1.ibd | innochecksum -
283 In this example, innochecksum writes the crc32 checksum algorithm
285 to a.ibd without changing the original t1.ibd file.
286 shell> cat t1.ibd | innochecksum --write=crc32 - > a.ibd
288 Running innochecksum on Multiple User-defined Tablespace Files
289 The following examples demonstrate how to run innochecksum on multiple
291 user-defined tablespace files (.ibd files).
292 Run innochecksum for all tablespace (.ibd) files in the “test”
294 database:
295 shell> innochecksum ./data/test/*.ibd
297 Run innochecksum for all tablespace files (.ibd files) that have a file
299 name starting with “t”:
300 shell> innochecksum ./data/test/t*.ibd
302 Run innochecksum for all tablespace files (.ibd files) in the data
304 directory:
305 shell> innochecksum ./data/*/*.ibd
307 Note
310 Running innochecksum on multiple user-defined tablespace files is
311 not supported on Windows operating systems, as Windows shells such
312 as cmd.exe do not support glob pattern expansion. On Windows
313 systems, innochecksum must be run separately for each user-defined
314 tablespace file. For example:
315 cmd> innochecksum.exe t1.ibd
317 cmd> innochecksum.exe t2.ibd
318 cmd> innochecksum.exe t3.ibd
319 Running innochecksum on Multiple System Tablespace Files
320 By default, there is only one InnoDB system tablespace file (ibdata1)
322 but multiple files for the system tablespace can be defined using the
323 innodb_data_file_path option. In the following example, three files for
324 the system tablespace are defined using the innodb_data_file_path
325 option: ibdata1, ibdata2, and ibdata3.
326 shell> ./bin/mysqld --no-defaults --innodb-data-file-path="ibdata1:10M;ibdata2:10M;ibdata3:10M:autoextend"
328 The three files (ibdata1, ibdata2, and ibdata3) form one logical system
330 tablespace. To run innochecksum on multiple files that form one logical
331 system tablespace, innochecksum requires the - option to read
332 tablespace files in from standard input, which is equivalent to
333 concatenating multiple files to create one single file. For the example
334 provided above, the following innochecksum command would be used:
335 shell> cat ibdata* | innochecksum -
337 Refer to the innochecksum options information for more information
339 about the “-” option.
340 Note
342 Running innochecksum on multiple files in the same tablespace is
343 not supported on Windows operating systems, as Windows shells such
344 as cmd.exe do not support glob pattern expansion. On Windows
345 systems, innochecksum must be run separately for each system
346 tablespace file. For example:
347 cmd> innochecksum.exe ibdata1
349 cmd> innochecksum.exe ibdata2
350 cmd> innochecksum.exe ibdata3
351
353 Copyright © 1997, 2020, Oracle and/or its affiliates. All rights
354 reserved.
355 This documentation is free software; you can redistribute it and/or
357 modify it only under the terms of the GNU General Public License as
358 published by the Free Software Foundation; version 2 of the License.
359 This documentation is distributed in the hope that it will be useful,
361 but WITHOUT ANY WARRANTY; without even the implied warranty of
362 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
363 General Public License for more details.
364 You should have received a copy of the GNU General Public License along
366 with the program; if not, write to the Free Software Foundation, Inc.,
367 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
368 http://www.gnu.org/licenses/.
369
372 For more information, please refer to the MySQL Reference Manual, which
373 may already be installed locally and which is also available online at
374 http://dev.mysql.com/doc/.
375
377 Oracle Corporation (http://dev.mysql.com/).
378MySQL 8.0 03/06/2020 INNOCHECKSUM(1)