aria_chk
Contents
aria_chk is used to check, repair, optimize, sort and get information about Aria tables.
With the MariaDB server you can use CHECK TABLE, REPAIR TABLE and OPTIMIZE TABLE to do similar things.
Note: aria_chk should not be used when MariaDB is running. MariaDB
assumes that no one is changing the tables it's using!
Usage:
aria_chk [OPTIONS] aria_tables[.MAI]
Aria table information is stored in 2 files: the .MAI file contains base
table information and the index and the .MAD file contains the data.
aria_chk takes one or more .MAI files as arguments.
The following groups are read from the my.cnf files:
[maria_chk][aria_chk]
Options and Variables
Global Options
The following options to handle option files may be given as the first argument:
| Option | Description |
|---|---|
| Print the program argument list and exit. |
| Don't read default options from any option file. |
| Only read default options from the given file #. |
| Read this file after the global files are read. |
Main Arguments
| Option | Description |
|---|---|
-, | Output debug log. Often this is 'd:t:o,filename'. |
-H, | Display this help and exit. |
-?, | Display this help and exit. |
| Path for control file (and logs if --logdir not used). |
| Don't open the control file. Only use this if you are sure the tables are not used by another program |
| Path for log files. |
| Abort if we can't find/read the maria_log_control file |
-s, | Only print errors. One can use two -s to make aria_chk very silent. |
-t, | Path for temporary files. Multiple paths can be specified, separated by colon (:) on Unix or semicolon (;) on Windows. They will be used in a round-robin fashion. |
-v, | Print more information. This can be used with --description and --check. Use many -v for more verbosity. |
-V, | Print version and exit. |
-w, | Wait if table is locked. |
Check Options (--check is the Default Action for aria_chk):
| Option | Description |
|---|---|
-c, | Check table for errors. |
-e, | Check the table VERY throughly. Only use this in extreme cases as aria_chk should normally be able to find out if the table is ok even without this switch. |
-F, | Check only tables that haven't been closed properly. |
-C, | Check only tables that have changed since last check. |
-f, | Restart with '-r' if there are any errors in the table. States will be updated as with '--update-state'. |
-i, | Print statistics information about table that is checked. |
-m, | Faster than extend-check, and finds 99.99% of all errors. Should be good enough for most cases. |
-U, | Mark tables as crashed if any errors were found and clean if check didn't find any errors but table was marked as 'not clean' before. This allows one to get rid of warnings like 'table not properly closed'. If table was updated, update also the timestamp for when the check was made. This option is on by default! Use --skip-update-state to disable. |
-T, | Don't mark table as checked. |
Recover (Repair) Options (When Using '--recover' or '--safe-recover'):
| Option | Description |
|---|---|
-B, | Make a backup of the .MAD file as 'filename-time.BAK'. |
| Correct checksum information for table. |
-D, | Max length of data file (when recreating data file when it's full). |
-e, | Try to recover every possible row from the data file Normally this will also find a lot of garbage rows; Don't use this option if you are not totally desperate. |
-f, | Overwrite old temporary files. |
-k, | Tell MARIA to update only some specific keys. # is a bit mask of which keys to use. This can be used to get faster inserts. |
| Skip rows bigger than this if aria_chk can't allocate memory to hold it. |
-r, | Can fix almost anything except unique keys that aren't unique. |
-n, | Forces recovering with sorting even if the temporary file would be very big. |
-p, | Uses the same technique as '-r' and '-n', but creates all the keys in parallel, in different threads. |
-o, | Uses old recovery method; Slower than '-r' but can handle a couple of cases where '-r' reports that it can't fix the data file. |
| Log repair command to transaction log. This is needed if one wants to use the maria_read_log to repeat the repair. |
| Directory where character sets are. |
| Change the collation used by the index. |
-q, | Faster repair by not modifying the data file. One can give a second '-q' to force aria_chk to modify the original datafile in case of duplicate keys. NOTE: Tables where the data file is currupted can't be fixed with this option. |
-u, | Unpack file packed with aria_pack. |
Other Options
| Option | Description |
|---|---|
-a, | Analyze distribution of keys. Will make some joins in MariaDB faster. You can check the calculated distribution by using '--description --verbose table_name'. |
| Specifies how index statistics collection code should treat NULLs. Possible values of name are "nulls_unequal" (default for 4.1/5.0), "nulls_equal" (emulate 4.0), and "nulls_ignored". |
-d, | Prints some information about table. |
-A, | Force auto_increment to start at this or higher value If no value is given, then sets the next auto_increment value to the highest used value for the auto key + 1. |
-S, | Sort index blocks. This speeds up 'read-next' in applications. |
-R, | Sort records according to an index. This makes your data much more localized and may speed up things (It may be VERY slow to do a sort the first time!). |
-b, | Find a record, a block at given offset belongs to. |
-z, | Remove transaction id's from the data and index files and fills empty space in the data and index files with zeroes. Zerofilling makes it possible to move the table from one system to another without the server having to do an automatic zerofill. It also allows one to compress the tables better if one want to archive them. |
| Like --zerofill but does not zero out LSN of data/index pages. |
Variables
| Option | Description |
|---|---|
page_buffer_size | Size of page buffer. Used by --safe-repair |
read_buffer_size | Read buffer size for sequential reads during scanning |
write_buffer_size | Write buffer size for sequential writes during repair of fixed size or dynamic size rows |
sort_buffer_size | Size of sort buffer. Used by --recover |
sort_key_blocks | Internal buffer for sorting keys; Don't touch :) |
Usage
One main usage of aria_chk is when you want to do a fast check of all Aria
tables in your system. This is faster than doing it in MariaDB as you can
allocate all free memory to the buffers.
Assuming you have a bit more than 2G free memory.
The following commands, run in the MariaDB data directory, check all your tables and repairs only those that have an error:
aria_chk --check --sort_order --force --sort_buffer_size=1G */*.MAI
If you want to optimize all your tables: (The --zerofill is
used here to fill up empty space with \0 which can speed up compressed backups).
aria_chk --analyze --sort-index --page_buffer_size=1G --zerofill */*.MAI
In case you have a serious problem and have to use --safe-recover:
aria_chk --safe-recover --zerofill --page_buffer_size=2G */*.MAI
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