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NAME

       innochecksum - offline InnoDB file checksum utility

SYNOPSIS

       innochecksum [options] file_name

DESCRIPTION

       innochecksum prints checksums for InnoDB files. This tool reads an InnoDB tablespace file,
       calculates the checksum for each page, compares the calculated checksum to the stored
       checksum, and reports mismatches, which indicate damaged pages. It was originally
       developed to speed up verifying the integrity of tablespace files after power outages but
       can also be used after file copies. Because checksum mismatches cause InnoDB to
       deliberately shut down a running server, it may be preferable to use this tool rather than
       waiting for an in-production server to encounter the damaged pages. As of MySQL 5.7.2,
       innochecksum supports files greater than 2GB in size. Previously, innochecksum only
       supported files up to 2GB in size.

       As of MySQL 5.7.2, innochecksum supports tablespaces that contain compressed pages.

       innochecksum cannot be used on tablespace files that the server already has open. For such
       files, you should use CHECK TABLE to check tables within the tablespace. Attempting to run
       innochecksum on a tablespace that the server already has open will result in an “Unable to
       lock file” error.

       If checksum mismatches are found, you would normally restore the tablespace from backup or
       start the server and attempt to use mysqldump to make a backup of the tables within the
       tablespace.

       Invoke innochecksum like this:

           shell> innochecksum [options] file_name

       innochecksum Options.PP innochecksum supports the following options. For options that
       refer to page numbers, the numbers are zero-based.

       ·   --help, -?

           Displays command line help. Example usage:

               shell> innochecksum --help

       ·   --info, -I

           Synonym for --help. Displays command line help. Example usage:

               shell> innochecksum --info

       ·   --version, -V

           Displays version information. Example usage:

               shell> innochecksum --version

       ·   --verbose, -v

           Verbose mode; prints a progress indicator to the log file every five seconds. In order
           for the progress indicator to be printed, the log file must be specified using the
           --log option. To turn on verbose mode, run:

               shell> innochecksum --verbose

           To turn off verbose mode, run:

               shell> innochecksum --verbose=FALSE

           The --verbose option and --log option can be specified at the same time. For example:

               shell> innochecksum --verbose --log=/var/lib/mysql/test/logtest.txt

           To locate the progress indicator information in the log file, you can perform the
           following search:

               shell> cat ./logtest.txt | grep -i "okay"

           The progress indicator information in the log file appears similar to the following:

               page 1663 okay: 2.863% done
               page 8447 okay: 14.537% done
               page 13695 okay: 23.568% done
               page 18815 okay: 32.379% done
               page 23039 okay: 39.648% done
               page 28351 okay: 48.789% done
               page 33023 okay: 56.828% done
               page 37951 okay: 65.308% done
               page 44095 okay: 75.881% done
               page 49407 okay: 85.022% done
               page 54463 okay: 93.722% done
               ...

       ·   --count, -c

           Print a count of the number of pages in the file and exit. Example usage:

               shell> innochecksum --count ../data/test/tab1.ibd

       ·   --start-page=num, -s num

           Start at this page number. Example usage:

               shell> innochecksum --start-page=600 ../data/test/tab1.ibd

           or:

               shell> innochecksum -s 600 ../data/test/tab1.ibd

       ·   --end-page=num, -e num

           End at this page number. Example usage:

               shell> innochecksum --end-page=700 ../data/test/tab1.ibd

           or:

               shell> innochecksum --p 700 ../data/test/tab1.ibd

       ·   --page=num, -p num

           Check only this page number. Example usage:

               shell> innochecksum --page=701 ../data/test/tab1.ibd

       ·   --strict-check, -C

           Specify a strict checksum algorithm. Options include innodb, crc32, and none.

           In this example, the innodb checksum algorithm is specified:

               shell> innochecksum --strict-check=innodb ../data/test/tab1.ibd

           In this example, the crc32 checksum algorithm is specified:

               shell> innochecksum -C crc32 ../data/test/tab1.ibd

           The following conditions apply:

           ·   If you do not specify the --strict-check option, innochecksum validates against
               innodb, crc32 and none.

           ·   If you specify the none option, only checksums generated by none are allowed.

           ·   If you specify the innodb option, only checksums generated by innodb are allowed.

           ·   If you specify the crc32 option, only checksums generated by crc32 are allowed.

       ·   --no-check, -n

           Ignore the checksum verification when rewriting a checksum. This option may only be
           used with the innochecksum --write option. If the --write option is not specified,
           innochecksum will terminate.

           In this example, an innodb checksum is rewritten to replace an invalid checksum:

               shell> innochecksum --no-check --write innodb ../data/test/tab1.ibd

       ·   --allow-mismatches, -a

           The maximum number of checksum mismatches allowed before innochecksum terminates. The
           default setting is 0. If --allow-mismatches=N, where N>=0, N mismatches are permitted
           and innochecksum terminates at N+1. When --allow-mismatches is set to 0, innochecksum
           terminates on the first checksum mismatch.

           In this example, an existing innodb checksum is rewritten to set --allow-mismatches to
           1.

               shell> innochecksum --allow-mismatches=1 --write innodb ../data/test/tab1.ibd

           With --allow-mismatches set to 1, if there is a mismatch at page 600 and another at
           page 700 on a file with 1000 pages, the checksum is updated for pages 0-599 and
           601-699. Because --allow-mismatches is set to 1, the checksum tolerates the first
           mismatch and terminates on the second mismatch, leaving page 600 and pages 700-999
           unchanged.

       ·   --write=name, -w num

           Rewrite a checksum. When rewriting an invalid checksum, the --no-check option must be
           used together with the --write option. The --no-check option tells innochecksum to
           ignore verification of the invalid checksum. You do not have to specify the --no-check
           option if the current checksum is valid.

           An algorithm must be specified when using the --write option. Possible values for the
           --write option are:

           ·   innodb: A checksum calculated in software, using the original algorithm from
               InnoDB.

           ·   crc32: A checksum calculated using the crc32 algorithm, possibly done with a
               hardware assist.

           ·   none: A constant number.

           The --write option rewrites entire pages to disk. If the new checksum is identical to
           the existing checksum, the new checksum is not written to disk in order to minimize
           I/O.

           innochecksum obtains an exclusive lock when the --write option is used.

           In this example, a crc32 checksum is written for tab1.ibd:

               shell> innochecksum -w crc32 ../data/test/tab1.ibd

           In this example, a crc32 checksum is rewritten to replace an invalid crc32 checksum:

               shell> innochecksum --no-check --write crc32 ../data/test/tab1.ibd

       ·   --page-type-summary, -S

           Display a count of each page type in a tablespace. Example usage:

               shell> innochecksum --page-type-summary ../data/test/tab1.ibd

           Sample output for --page-type-summary:

               File::../data/test/tab1.ibd
               ================PAGE TYPE SUMMARY==============
               #PAGE_COUNT PAGE_TYPE
               ===============================================
                      2        Index page
                      0        Undo log page
                      1        Inode page
                      0        Insert buffer free list page
                      2        Freshly allocated page
                      1        Insert buffer bitmap
                      0        System page
                      0        Transaction system page
                      1        File Space Header
                      0        Extent descriptor page
                      0        BLOB page
                      0        Compressed BLOB page
                      0        Other type of page
               ===============================================
               Additional information:
               Undo page type: 0 insert, 0 update, 0 other
               Undo page state: 0 active, 0 cached, 0 to_free, 0 to_purge, 0 prepared, 0 other

       ·   --page-type-dump, -D

           Dump the page type information for each page in a tablespace to stderr or stdout.
           Example usage:

               shell> innochecksum --page-type-dump=/tmp/a.txt ../data/test/tab1.ibd

       ·   --log, -l

           Log output for the innochecksum tool. A log file name must be provided. Log output
           contains checksum values for each tablespace page. For uncompressed tables, LSN values
           are also provided. The --log replaces the --debug option, which was available in
           earlier releases. Example usage:

               shell> innochecksum --log=/tmp/log.txt ../data/test/tab1.ibd

           or:

               shell> innochecksum -l /tmp/log.txt ../data/test/tab1.ibd

       ·   - option.

           Specify the - option to read from standard input. If the - option is missing when
           “read from standard in” is expected, innochecksum will output innochecksum usage
           information indicating that the “-” option was omitted. Example usages:

               shell> cat t1.ibd | innochecksum -

           In this example, innochecksum writes the crc32 checksum algorithm to a.ibd without
           changing the original t1.ibd file.

               shell> cat t1.ibd | innochecksum --write=crc32 - > a.ibd
       Running innochecksum on Multiple User-defined Tablespace Files.PP The following examples
       demonstrate how to run innochecksum on multiple user-defined tablespace files (.ibd
       files).

       Run innochecksum for all tablespace (.ibd) files in the “test” database:

           shell> innochecksum ./data/test/*.ibd

       Run innochecksum for all tablespace files (.ibd files) that have a file name starting with
       “t”:

           shell> innochecksum ./data/test/t*.ibd

       Run innochecksum for all tablespace files (.ibd files) in the data directory:

           shell> innochecksum ./data/*/*.ibd

           Note
           Running innochecksum on multiple user-defined tablespace files is not supported on
           Windows operating systems, as Windows shells such as cmd.exe do not support glob
           pattern expansion. On Windows systems, innochecksum must be run separately for each
           user-defined tablespace file. For example:

               cmd> innochecksum.exe t1.ibd
               cmd> innochecksum.exe t2.ibd
               cmd> innochecksum.exe t3.ibd
       Running innochecksum on Multiple System Tablespace Files.PP By default, there is only one
       InnoDB system tablespace file (ibdata1) but multiple files for the system tablespace can
       be defined using the innodb_data_file_path option. In the following example, three files
       for the system tablespace are defined using the innodb_data_file_path option: ibdata1,
       ibdata2, and ibdata3.

           shell> ./bin/mysqld --no-defaults --innodb-data-file-path="ibdata1:10M;ibdata2:10M;ibdata3:10M:autoextend"

       The three files (ibdata1, ibdata2, and ibdata3) form one logical system tablespace. To run
       innochecksum on multiple files that form one logical system tablespace, innochecksum
       requires the - option to read tablespace files in from standard input, which is equivalent
       to concatenating multiple files to create one single file. For the example provided above,
       the following innochecksum command would be used:

             shell> cat ibdata* | innochecksum -

       Refer to the innochecksum options information for more information about the “-” option.

           Note
           Running innochecksum on multiple files in the same tablespace is not supported on
           Windows operating systems, as Windows shells such as cmd.exe do not support glob
           pattern expansion. On Windows systems, innochecksum must be run separately for each
           system tablespace file. For example:

               cmd> innochecksum.exe ibdata1
               cmd> innochecksum.exe ibdata2
               cmd> innochecksum.exe ibdata3

COPYRIGHT

       Copyright © 1997, 2017, Oracle and/or its affiliates. All rights reserved.

       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.

       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.

       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/.

SEE ALSO

       For more information, please refer to the MySQL Reference Manual, which may already be
       installed locally and which is also available online at http://dev.mysql.com/doc/.

AUTHOR

       Oracle Corporation (http://dev.mysql.com/).