| PT-ARCHIVER(1p) | User Contributed Perl Documentation | PT-ARCHIVER(1p) |
pt-archiver - Archive rows from a MySQL table into another table or a file.
Usage: pt-archiver [OPTIONS] --source DSN --where WHERE
pt-archiver nibbles records from a MySQL table. The --source and --dest arguments use DSN syntax; if COPY is yes, --dest defaults to the key's value from --source.
Examples:
Archive all rows from oltp_server to olap_server and to a file:
pt-archiver --source h=oltp_server,D=test,t=tbl --dest h=olap_server \
--file '/var/log/archive/%Y-%m-%d-%D.%t' \
--where "1=1" --limit 1000 --commit-each
Purge (delete) orphan rows from child table:
pt-archiver --source h=host,D=db,t=child --purge \
--where 'NOT EXISTS(SELECT * FROM parent WHERE col=child.col)'
Percona Toolkit is mature, proven in the real world, and well tested, but all database tools can pose a risk to the system and the database server. Before using this tool, please:
pt-archiver is the tool I use to archive tables as described in <http://tinyurl.com/mysql-archiving>. The goal is a low-impact, forward-only job to nibble old data out of the table without impacting OLTP queries much. You can insert the data into another table, which need not be on the same server. You can also write it to a file in a format suitable for LOAD DATA INFILE. Or you can do neither, in which case it's just an incremental DELETE.
pt-archiver is extensible via a plugin mechanism. You can inject your own code to add advanced archiving logic that could be useful for archiving dependent data, applying complex business rules, or building a data warehouse during the archiving process.
You need to choose values carefully for some options. The most important are "--limit", "--retries", and "--txn-size".
The strategy is to find the first row(s), then scan some index forward-only to find more rows efficiently. Each subsequent query should not scan the entire table; it should seek into the index, then scan until it finds more archivable rows. Specifying the index with the 'i' part of the "--source" argument can be crucial for this; use "--dry-run" to examine the generated queries and be sure to EXPLAIN them to see if they are efficient (most of the time you probably want to scan the PRIMARY key, which is the default). Even better, examine the difference in the Handler status counters before and after running the query, and make sure it is not scanning the whole table every query.
You can disable the seek-then-scan optimizations partially or wholly with "--no-ascend" and "--ascend-first". Sometimes this may be more efficient for multi-column keys. Be aware that pt-archiver is built to start at the beginning of the index it chooses and scan it forward-only. This might result in long table scans if you're trying to nibble from the end of the table by an index other than the one it prefers. See "--source" and read the documentation on the "i" part if this applies to you.
pt-archiver works with Percona XtraDB Cluster (PXC) 5.5.28-23.7 and newer, but there are three limitations you should consider before archiving on a cluster:
If you specify "--progress", the output is a header row, plus status output at intervals. Each row in the status output lists the current date and time, how many seconds pt-archiver has been running, and how many rows it has archived.
If you specify "--statistics", "pt-archiver" outputs timing and other information to help you identify which part of your archiving process takes the most time.
pt-archiver tries to catch signals and exit gracefully; for example, if you send it SIGTERM (Ctrl-C on UNIX-ish systems), it will catch the signal, print a message about the signal, and exit fairly normally. It will not execute "--analyze" or "--optimize", because these may take a long time to finish. It will run all other code normally, including calling after_finish() on any plugins (see "EXTENDING").
In other words, a signal, if caught, will break out of the main archiving loop and skip optimize/analyze.
Specify at least one of "--dest", "--file", or "--purge".
"--ignore" and "--replace" are mutually exclusive.
"--txn-size" and "--commit-each" are mutually exclusive.
"--low-priority-insert" and "--delayed-insert" are mutually exclusive.
"--share-lock" and "--for-update" are mutually exclusive.
"--analyze" and "--optimize" are mutually exclusive.
"--no-ascend" and "--no-delete" are mutually exclusive.
DSN values in "--dest" default to values from "--source" if COPY is yes.
Run ANALYZE TABLE afterwards on "--source" and/or "--dest".
Runs ANALYZE TABLE after finishing. The argument is an arbitrary string. If it contains the letter 's', the source will be analyzed. If it contains 'd', the destination will be analyzed. You can specify either or both. For example, the following will analyze both:
--analyze=ds
See <http://dev.mysql.com/doc/en/analyze-table.html> for details on ANALYZE TABLE.
If you do want to use the ascending index optimization (see "--no-ascend"), but do not want to incur the overhead of ascending a large multi-column index, you can use this option to tell pt-archiver to ascend only the leftmost column of the index. This can provide a significant performance boost over not ascending the index at all, while avoiding the cost of ascending the whole index.
See "EXTENDING" for a discussion of how this interacts with plugins.
Disables autoflushing to "--file" and flushes "--file" to disk only when a transaction commits. This typically means the file is block-flushed by the operating system, so there may be some implicit flushes to disk between commits as well. The default is to flush "--file" to disk after every row.
The danger is that a crash might cause lost data.
The performance increase I have seen from using "--buffer" is around 5 to 15 percent. Your mileage may vary.
Delete each chunk of rows in bulk with a single "DELETE" statement. The statement deletes every row between the first and last row of the chunk, inclusive. It implies "--commit-each", since it would be a bad idea to "INSERT" rows one at a time and commit them before the bulk "DELETE".
The normal method is to delete every row by its primary key. Bulk deletes might be a lot faster. They also might not be faster if you have a complex "WHERE" clause.
This option completely defers all "DELETE" processing until the chunk of rows is finished. If you have a plugin on the source, its "before_delete" method will not be called. Instead, its "before_bulk_delete" method is called later.
WARNING: if you have a plugin on the source that sometimes doesn't return true from "is_archivable()", you should use this option only if you understand what it does. If the plugin instructs "pt-archiver" not to archive a row, it will still be deleted by the bulk delete!
Add "--limit" to "--bulk-delete" statement.
This is an advanced option and you should not disable it unless you know what you are doing and why! By default, "--bulk-delete" appends a "--limit" clause to the bulk delete SQL statement. In certain cases, this clause can be omitted by specifying "--no-bulk-delete-limit". "--limit" must still be specified.
Insert each chunk of rows with "LOAD DATA LOCAL INFILE". This may be much faster than inserting a row at a time with "INSERT" statements. It is implemented by creating a temporary file for each chunk of rows, and writing the rows to this file instead of inserting them. When the chunk is finished, it uploads the rows.
To protect the safety of your data, this option forces bulk deletes to be used. It would be unsafe to delete each row as it is found, before inserting the rows into the destination first. Forcing bulk deletes guarantees that the deletion waits until the insertion is successful.
The "--low-priority-insert", "--replace", and "--ignore" options work with this option, but "--delayed-insert" does not.
If "LOAD DATA LOCAL INFILE" throws an error in the lines of "The used command is not allowed with this MySQL version", refer to the documentation for the "L" DSN option.
Channel name used when connected to a server using replication channels. Suppose you have two masters, master_a at port 12345, master_b at port 1236 and a slave connected to both masters using channels chan_master_a and chan_master_b. If you want to run pt-archiver to syncronize the slave against master_a, pt-archiver won't be able to determine what's the correct master since SHOW SLAVE STATUS will return 2 rows. In this case, you can use --channel=chan_master_a to specify the channel name to use in the SHOW SLAVE STATUS command.
Default character set. If the value is utf8, sets Perl's binmode on STDOUT to utf8, passes the mysql_enable_utf8 option to DBD::mysql, and runs SET NAMES UTF8 after connecting to MySQL. Any other value sets binmode on STDOUT without the utf8 layer, and runs SET NAMES after connecting to MySQL.
Note that only charsets as known by MySQL are recognized; So for example, "UTF8" will work, but "UTF-8" will not.
See also "--[no]check-charset".
Ensure connection and table character sets are the same. Disabling this check may cause text to be erroneously converted from one character set to another (usually from utf8 to latin1) which may cause data loss or mojibake. Disabling this check may be useful or necessary when character set conversions are intended.
Ensure "--source" and "--dest" have same columns.
Enabled by default; causes pt-archiver to check that the source and destination tables have the same columns. It does not check column order, data type, etc. It just checks that all columns in the source exist in the destination and vice versa. If there are any differences, pt-archiver will exit with an error.
To disable this check, specify --no-check-columns.
If "--check-slave-lag" is given, this defines how
long the tool pauses each
time it discovers that a slave is lagging.
This check is performed every 100 rows.
Pause archiving until the specified DSN's slave lag is less than "--max-lag". This option can be specified multiple times for checking more than one slave.
Comma-separated list of columns to archive.
Specify a comma-separated list of columns to fetch, write to the file, and insert into the destination table. If specified, pt-archiver ignores other columns unless it needs to add them to the "SELECT" statement for ascending an index or deleting rows. It fetches and uses these extra columns internally, but does not write them to the file or to the destination table. It does pass them to plugins.
See also "--primary-key-only".
Commits transactions and flushes "--file" after each set of rows has been archived, before fetching the next set of rows, and before sleeping if "--sleep" is specified. Disables "--txn-size"; use "--limit" to control the transaction size with "--commit-each".
This option is useful as a shortcut to make "--limit" and "--txn-size" the same value, but more importantly it avoids transactions being held open while searching for more rows. For example, imagine you are archiving old rows from the beginning of a very large table, with "--limit" 1000 and "--txn-size" 1000. After some period of finding and archiving 1000 rows at a time, pt-archiver finds the last 999 rows and archives them, then executes the next SELECT to find more rows. This scans the rest of the table, but never finds any more rows. It has held open a transaction for a very long time, only to determine it is finished anyway. You can use "--commit-each" to avoid this.
Read this comma-separated list of config files; if specified, this must be the first option on the command line.
Connect to this database.
Adds the DELAYED modifier to INSERT or REPLACE statements. See <http://dev.mysql.com/doc/en/insert.html> for details.
DSN specifying the table to archive to.
This item specifies a table into which pt-archiver will insert rows archived from "--source". It uses the same key=val argument format as "--source". Most missing values default to the same values as "--source", so you don't have to repeat options that are the same in "--source" and "--dest". Use the "--help" option to see which values are copied from "--source".
WARNING: Using a default options file (F) DSN option that defines a socket for "--source" causes pt-archiver to connect to "--dest" using that socket unless another socket for "--dest" is specified. This means that pt-archiver may incorrectly connect to "--source" when it connects to "--dest". For example:
--source F=host1.cnf,D=db,t=tbl --dest h=host2
When pt-archiver connects to "--dest", host2, it will connect via the "--source", host1, socket defined in host1.cnf.
Causes pt-archiver to exit after printing the filename and SQL statements it will use.
File to archive to, with DATE_FORMAT()-like formatting.
Filename to write archived rows to. A subset of MySQL's DATE_FORMAT() formatting codes are allowed in the filename, as follows:
%d Day of the month, numeric (01..31)
%H Hour (00..23)
%i Minutes, numeric (00..59)
%m Month, numeric (01..12)
%s Seconds (00..59)
%Y Year, numeric, four digits
You can use the following extra format codes too:
%D Database name
%t Table name
Example:
--file '/var/log/archive/%Y-%m-%d-%D.%t'
The file's contents are in the same format used by SELECT INTO OUTFILE, as documented in the MySQL manual: rows terminated by newlines, columns terminated by tabs, NULL characters are represented by "\N", and special characters are escaped by "\". This lets you reload a file with LOAD DATA INFILE's default settings.
If you want a column header at the top of the file, see "--header". The file is auto-flushed by default; see "--buffer".
For details, see <http://dev.mysql.com/doc/en/innodb-locking-reads.html>.
Writes column names as the first line in the file given by "--file". If the file exists, does not write headers; this keeps the file loadable with LOAD DATA INFILE in case you append more output to it.
See <http://dev.mysql.com/doc/en/select.html> for details.
Connect to host.
Causes INSERTs into "--dest" to be INSERT IGNORE.
Number of rows to fetch and archive per statement.
Limits the number of rows returned by the SELECT statements that retrieve rows to archive. Default is one row. It may be more efficient to increase the limit, but be careful if you are archiving sparsely, skipping over many rows; this can potentially cause more contention with other queries, depending on the storage engine, transaction isolation level, and options such as "--for-update".
Adds the NO_WRITE_TO_BINLOG modifier to ANALYZE and OPTIMIZE queries. See "--analyze" for details.
See <http://dev.mysql.com/doc/en/delete.html> for details.
See <http://dev.mysql.com/doc/en/insert.html> for details.
Somewhat similar to --max-lag but for PXC clusters. Check average time cluster spent pausing for Flow Control and make tool pause if it goes over the percentage indicated in the option. Default is no Flow Control checking. This option is available for PXC versions 5.6 or higher.
Pause archiving if the slave given by "--check-slave-lag" lags.
This option causes pt-archiver to look at the slave every time it's about to fetch another row. If the slave's lag is greater than the option's value, or if the slave isn't running (so its lag is NULL), pt-table-checksum sleeps for "--check-interval" seconds and then looks at the lag again. It repeats until the slave is caught up, then proceeds to fetch and archive the row.
This option may eliminate the need for "--sleep" or "--sleep-coef".
The default ascending-index optimization causes "pt-archiver" to optimize repeated "SELECT" queries so they seek into the index where the previous query ended, then scan along it, rather than scanning from the beginning of the table every time. This is enabled by default because it is generally a good strategy for repeated accesses.
Large, multiple-column indexes may cause the WHERE clause to be complex enough that this could actually be less efficient. Consider for example a four-column PRIMARY KEY on (a, b, c, d). The WHERE clause to start where the last query ended is as follows:
WHERE (a > ?)
OR (a = ? AND b > ?)
OR (a = ? AND b = ? AND c > ?)
OR (a = ? AND b = ? AND c = ? AND d >= ?)
Populating the placeholders with values uses memory and CPU, adds network traffic and parsing overhead, and may make the query harder for MySQL to optimize. A four-column key isn't a big deal, but a ten-column key in which every column allows "NULL" might be.
Ascending the index might not be necessary if you know you are simply removing rows from the beginning of the table in chunks, but not leaving any holes, so starting at the beginning of the table is actually the most efficient thing to do.
See also "--ascend-first". See "EXTENDING" for a discussion of how this interacts with plugins.
Causes "pt-archiver" not to delete rows after processing them. This disallows "--no-ascend", because enabling them both would cause an infinite loop.
If there is a plugin on the source DSN, its "before_delete" method is called anyway, even though "pt-archiver" will not execute the delete. See "EXTENDING" for more on plugins.
Run OPTIMIZE TABLE afterwards on "--source" and/or "--dest".
Runs OPTIMIZE TABLE after finishing. See "--analyze" for the option syntax and <http://dev.mysql.com/doc/en/optimize-table.html> for details on OPTIMIZE TABLE.
Used with "--file" to specify the output format.
Valid formats are:
- dump: MySQL dump format using tabs as field separator (default)
- csv : Dump rows using ',' as separator and optionally
enclosing fields by '"'.
This format is equivalent to FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED
BY '"'.
Password to use when connecting. If password contains commas they must be escaped with a backslash: "exam\,ple"
Create the given PID file. The tool won't start if the PID file already exists and the PID it contains is different than the current PID. However, if the PID file exists and the PID it contains is no longer running, the tool will overwrite the PID file with the current PID. The PID file is removed automatically when the tool exits.
Perl module name to use as a generic plugin.
Specify the Perl module name of a general-purpose plugin. It is currently used only for statistics (see "--statistics") and must have "new()" and a "statistics()" method.
The "new( src => $src, dst => $dst, opts => $o )" method gets the source and destination DSNs, and their database connections, just like the connection-specific plugins do. It also gets an OptionParser object ($o) for accessing command-line options (example: "$o->get('purge');").
The "statistics(\%stats, $time)" method gets a hashref of the statistics collected by the archiving job, and the time the whole job started.
Port number to use for connection.
A shortcut for specifying "--columns" with the primary key columns. This is an efficiency if you just want to purge rows; it avoids fetching the entire row, when only the primary key columns are needed for "DELETE" statements. See also "--purge".
Print progress information every X rows.
Prints current time, elapsed time, and rows archived every X rows.
Allows archiving without a "--file" or "--dest" argument, which is effectively a purge since the rows are just deleted.
If you just want to purge rows, consider specifying the table's primary key columns with "--primary-key-only". This will prevent fetching all columns from the server for no reason.
See <http://dev.mysql.com/doc/en/delete.html> for details. As stated in the documentation, in some cases it may be faster to use DELETE QUICK followed by OPTIMIZE TABLE. You can use "--optimize" for this.
Do not print any output, such as for "--statistics".
Suppresses normal output, including the output of "--statistics", but doesn't suppress the output from "--why-quit".
Number of retries per timeout or deadlock.
Specifies the number of times pt-archiver should retry when there is an InnoDB lock wait timeout or deadlock. When retries are exhausted, pt-archiver will exit with an error.
Consider carefully what you want to happen when you are archiving between a mixture of transactional and non-transactional storage engines. The INSERT to "--dest" and DELETE from "--source" are on separate connections, so they do not actually participate in the same transaction even if they're on the same server. However, pt-archiver implements simple distributed transactions in code, so commits and rollbacks should happen as desired across the two connections.
At this time I have not written any code to handle errors with transactional storage engines other than InnoDB. Request that feature if you need it.
Time to run before exiting.
Optional suffix s=seconds, m=minutes, h=hours, d=days; if no suffix, s is used.
Do not archive row with max AUTO_INCREMENT.
Adds an extra WHERE clause to prevent pt-archiver from removing the newest row when ascending a single-column AUTO_INCREMENT key. This guards against re-using AUTO_INCREMENT values if the server restarts, and is enabled by default.
The extra WHERE clause contains the maximum value of the auto-increment column as of the beginning of the archive or purge job. If new rows are inserted while pt-archiver is running, it will not see them.
Exit if this file exists.
The presence of the file specified by "--sentinel" will cause pt-archiver to stop archiving and exit. The default is /tmp/pt-archiver-sentinel. You might find this handy to stop cron jobs gracefully if necessary. See also "--stop".
Sets the user to be used to connect to the slaves. This parameter allows you to have a different user with less privileges on the slaves but that user must exist on all slaves.
Sets the password to be used to connect to the slaves. It can be used with --slave-user and the password for the user must be the same on all slaves.
Set the MySQL variables in this comma-separated list of "variable=value" pairs.
By default, the tool sets:
wait_timeout=10000
Variables specified on the command line override these defaults. For example, specifying "--set-vars wait_timeout=500" overrides the default value of 10000.
The tool prints a warning and continues if a variable cannot be set.
See <http://dev.mysql.com/doc/en/innodb-locking-reads.html>.
Sleep time between fetches.
Specifies how long to sleep between SELECT statements. Default is not to sleep at all. Transactions are NOT committed, and the "--file" file is NOT flushed, before sleeping. See "--txn-size" to control that.
If "--commit-each" is specified, committing and flushing happens before sleeping.
Calculate "--sleep" as a multiple of the last SELECT time.
If this option is specified, pt-archiver will sleep for the query time of the last SELECT multiplied by the specified coefficient.
This is a slightly more sophisticated way to throttle the SELECTs: sleep a varying amount of time between each SELECT, depending on how long the SELECTs are taking.
Socket file to use for connection.
DSN specifying the table to archive from (required). This argument is a DSN. See "DSN OPTIONS" for the syntax. Most options control how pt-archiver connects to MySQL, but there are some extended DSN options in this tool's syntax. The D, t, and i options select a table to archive:
--source h=my_server,D=my_database,t=my_tbl
The a option specifies the database to set as the connection's default with USE. If the b option is true, it disables binary logging with SQL_LOG_BIN. The m option specifies pluggable actions, which an external Perl module can provide. The only required part is the table; other parts may be read from various places in the environment (such as options files).
The 'i' part deserves special mention. This tells pt-archiver which index it should scan to archive. This appears in a FORCE INDEX or USE INDEX hint in the SELECT statements used to fetch archivable rows. If you don't specify anything, pt-archiver will auto-discover a good index, preferring a "PRIMARY KEY" if one exists. In my experience this usually works well, so most of the time you can probably just omit the 'i' part.
The index is used to optimize repeated accesses to the table; pt-archiver remembers the last row it retrieves from each SELECT statement, and uses it to construct a WHERE clause, using the columns in the specified index, that should allow MySQL to start the next SELECT where the last one ended, rather than potentially scanning from the beginning of the table with each successive SELECT. If you are using external plugins, please see "EXTENDING" for a discussion of how they interact with ascending indexes.
The 'a' and 'b' options allow you to control how statements flow through the binary log. If you specify the 'b' option, binary logging will be disabled on the specified connection. If you specify the 'a' option, the connection will "USE" the specified database, which you can use to prevent slaves from executing the binary log events with "--replicate-ignore-db" options. These two options can be used as different methods to achieve the same goal: archive data off the master, but leave it on the slave. For example, you can run a purge job on the master and prevent it from happening on the slave using your method of choice.
WARNING: Using a default options file (F) DSN option that defines a socket for "--source" causes pt-archiver to connect to "--dest" using that socket unless another socket for "--dest" is specified. This means that pt-archiver may incorrectly connect to "--source" when it is meant to connect to "--dest". For example:
--source F=host1.cnf,D=db,t=tbl --dest h=host2
When pt-archiver connects to "--dest", host2, it will connect via the "--source", host1, socket defined in host1.cnf.
Causes pt-archiver to collect timing statistics about what it does. These statistics are available to the plugin specified by "--plugin"
Unless you specify "--quiet", "pt-archiver" prints the statistics when it exits. The statistics look like this:
Started at 2008-07-18T07:18:53, ended at 2008-07-18T07:18:53
Source: D=db,t=table
SELECT 4
INSERT 4
DELETE 4
Action Count Time Pct
commit 10 0.1079 88.27
select 5 0.0047 3.87
deleting 4 0.0028 2.29
inserting 4 0.0028 2.28
other 0 0.0040 3.29
The first two (or three) lines show times and the source and destination tables. The next three lines show how many rows were fetched, inserted, and deleted.
The remaining lines show counts and timing. The columns are the action, the total number of times that action was timed, the total time it took, and the percent of the program's total runtime. The rows are sorted in order of descending total time. The last row is the rest of the time not explicitly attributed to anything. Actions will vary depending on command-line options.
If "--why-quit" is given, its behavior is changed slightly. This option causes it to print the reason for exiting even when it's just because there are no more rows.
This option requires the standard Time::HiRes module, which is part of core Perl on reasonably new Perl releases.
Causes pt-archiver to create the sentinel file specified by "--sentinel" and exit. This should have the effect of stopping all running instances which are watching the same sentinel file.
Number of rows per transaction.
Specifies the size, in number of rows, of each transaction. Zero disables transactions altogether. After pt-archiver processes this many rows, it commits both the "--source" and the "--dest" if given, and flushes the file given by "--file".
This parameter is critical to performance. If you are archiving from a live server, which for example is doing heavy OLTP work, you need to choose a good balance between transaction size and commit overhead. Larger transactions create the possibility of more lock contention and deadlocks, but smaller transactions cause more frequent commit overhead, which can be significant. To give an idea, on a small test set I worked with while writing pt-archiver, a value of 500 caused archiving to take about 2 seconds per 1000 rows on an otherwise quiet MySQL instance on my desktop machine, archiving to disk and to another table. Disabling transactions with a value of zero, which turns on autocommit, dropped performance to 38 seconds per thousand rows.
If you are not archiving from or to a transactional storage engine, you may want to disable transactions so pt-archiver doesn't try to commit.
User for login if not current user.
Check for the latest version of Percona Toolkit, MySQL, and other programs.
This is a standard "check for updates automatically" feature, with two additional features. First, the tool checks its own version and also the versions of the following software: operating system, Percona Monitoring and Management (PMM), MySQL, Perl, MySQL driver for Perl (DBD::mysql), and Percona Toolkit. Second, it checks for and warns about versions with known problems. For example, MySQL 5.5.25 had a critical bug and was re-released as 5.5.25a.
A secure connection to Percona's Version Check database server is done to perform these checks. Each request is logged by the server, including software version numbers and unique ID of the checked system. The ID is generated by the Percona Toolkit installation script or when the Version Check database call is done for the first time.
Any updates or known problems are printed to STDOUT before the tool's normal output. This feature should never interfere with the normal operation of the tool.
For more information, visit <https://www.percona.com/doc/percona-toolkit/LATEST/version-check.html>.
WHERE clause to limit which rows to archive (required).
Specifies a WHERE clause to limit which rows are archived. Do not include the word WHERE. You may need to quote the argument to prevent your shell from interpreting it. For example:
--where 'ts < current_date - interval 90 day'
For safety, "--where" is required. If you do not require a WHERE clause, use "--where" 1=1.
Causes pt-archiver to print a message if it exits for any reason other than running out of rows to archive. This can be useful if you have a cron job with "--run-time" specified, for example, and you want to be sure pt-archiver is finishing before running out of time.
If "--statistics" is given, the behavior is changed slightly. It will print the reason for exiting even when it's just because there are no more rows.
This output prints even if "--quiet" is given. That's so you can put "pt-archiver" in a "cron" job and get an email if there's an abnormal exit.
These DSN options are used to create a DSN. Each option is given like "option=value". The options are case-sensitive, so P and p are not the same option. There cannot be whitespace before or after the "=" and if the value contains whitespace it must be quoted. DSN options are comma-separated. See the percona-toolkit manpage for full details.
copy: no
Database to USE when executing queries.
dsn: charset; copy: yes
Default character set.
copy: no
If true, disable binlog with SQL_LOG_BIN.
dsn: database; copy: yes
Database that contains the table.
dsn: mysql_read_default_file; copy: yes
Only read default options from the given file
dsn: host; copy: yes
Connect to host.
copy: yes
Index to use.
copy: yes
Explicitly enable LOAD DATA LOCAL INFILE.
For some reason, some vendors compile libmysql without the --enable-local-infile option, which disables the statement. This can lead to weird situations, like the server allowing LOCAL INFILE, but the client throwing exceptions if it's used.
However, as long as the server allows LOAD DATA, clients can easily re-enable it; See <https://dev.mysql.com/doc/refman/5.0/en/load-data-local.html> and <http://search.cpan.org/~capttofu/DBD-mysql/lib/DBD/mysql.pm>. This option does exactly that.
Although we've not found a case where turning this option leads to errors or differing behavior, to be on the safe side, this option is not on by default.
copy: no
Plugin module name.
dsn: password; copy: yes
Password to use when connecting. If password contains commas they must be escaped with a backslash: "exam\,ple"
dsn: port; copy: yes
Port number to use for connection.
dsn: mysql_socket; copy: yes
Socket file to use for connection.
copy: yes
Table to archive from/to.
dsn: user; copy: yes
User for login if not current user.
pt-archiver is extensible by plugging in external Perl modules to handle some logic and/or actions. You can specify a module for both the "--source" and the "--dest", with the 'm' part of the specification. For example:
--source D=test,t=test1,m=My::Module1 --dest m=My::Module2,t=test2
This will cause pt-archiver to load the My::Module1 and My::Module2 packages, create instances of them, and then make calls to them during the archiving process.
You can also specify a plugin with "--plugin".
The module must provide this interface:
The "cols" argument is the column names the user requested to be archived, either by default or by the "--columns" option. The "allcols" argument is the list of column names for every row pt-archiver will fetch from the source table. It may fetch more columns than the user requested, because it needs some columns for its own use. When subsequent plugin functions receive a row, it is the full row containing all the extra columns, if any, added to the end.
Skipping a row adds complications for non-unique indexes. Normally pt-archiver uses a WHERE clause designed to target the last processed row as the place to start the scan for the next SELECT statement. If you have skipped the row by returning false from is_archivable(), pt-archiver could get into an infinite loop because the row still exists. Therefore, when you specify a plugin for the "--source" argument, pt-archiver will change its WHERE clause slightly. Instead of starting at "greater than or equal to" the last processed row, it will start "strictly greater than." This will work fine on unique indexes such as primary keys, but it may skip rows (leave holes) on non-unique indexes or when ascending only the first column of an index.
"pt-archiver" will change the clause in the same way if you specify "--no-delete", because again an infinite loop is possible.
If you specify the "--bulk-delete" option and return false from this method, "pt-archiver" may not do what you want. The row won't be archived, but it will be deleted, since bulk deletes operate on ranges of rows and don't know which rows the plugin selected to keep.
If you specify the "--bulk-insert" option, this method's return value will influence whether the row is written to the temporary file for the bulk insert, so bulk inserts will work as expected. However, bulk inserts require bulk deletes.
This plugin method is called even if "--no-delete" is given, but not if "--bulk-delete" is given.
This method is not called if "--bulk-insert" is given.
If no value is returned, the default "INSERT" statement handle is used.
This method applies only to the plugin specified for "--dest", so if your plugin isn't doing what you expect, check that you've specified it for the destination and not the source.
This method's return value etc is similar to the "custom_sth()" method.
If you specify a plugin for both "--source" and "--dest", pt-archiver constructs, calls before_begin(), and calls after_finish() on the two plugins in the order "--source", "--dest".
pt-archiver assumes it controls transactions, and that the plugin will NOT commit or roll back the database handle. The database handle passed to the plugin's constructor is the same handle pt-archiver uses itself. Remember that "--source" and "--dest" are separate handles.
A sample module might look like this:
package My::Module;
sub new {
my ( $class, %args ) = @_;
return bless(\%args, $class);
}
sub before_begin {
my ( $self, %args ) = @_;
# Save column names for later
$self->{cols} = $args{cols};
}
sub is_archivable {
my ( $self, %args ) = @_;
# Do some advanced logic with $args{row}
return 1;
}
sub before_delete {} # Take no action
sub before_insert {} # Take no action
sub custom_sth {} # Take no action
sub after_finish {} # Take no action
1;
The environment variable "PTDEBUG" enables verbose debugging output to STDERR. To enable debugging and capture all output to a file, run the tool like:
PTDEBUG=1 pt-archiver ... > FILE 2>&1
Be careful: debugging output is voluminous and can generate several megabytes of output.
You need Perl, DBI, DBD::mysql, and some core packages that ought to be installed in any reasonably new version of Perl.
For a list of known bugs, see <http://www.percona.com/bugs/pt-archiver>.
Please report bugs at <https://jira.percona.com/projects/PT>. Include the following information in your bug report:
If possible, include debugging output by running the tool with "PTDEBUG"; see "ENVIRONMENT".
Visit <http://www.percona.com/software/percona-toolkit/> to download the latest release of Percona Toolkit. Or, get the latest release from the command line:
wget percona.com/get/percona-toolkit.tar.gz wget percona.com/get/percona-toolkit.rpm wget percona.com/get/percona-toolkit.deb
You can also get individual tools from the latest release:
wget percona.com/get/TOOL
Replace "TOOL" with the name of any tool.
Baron Schwartz
Andrew O'Brien
This tool is part of Percona Toolkit, a collection of advanced command-line tools for MySQL developed by Percona. Percona Toolkit was forked from two projects in June, 2011: Maatkit and Aspersa. Those projects were created by Baron Schwartz and primarily developed by him and Daniel Nichter. Visit <http://www.percona.com/software/> to learn about other free, open-source software from Percona.
This program is copyright 2011-2018 Percona LLC and/or its affiliates, 2007-2011 Baron Schwartz.
THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2; OR the Perl Artistic License. On UNIX and similar systems, you can issue `man perlgpl' or `man perlartistic' to read these licenses.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
pt-archiver 3.2.1
| 2020-08-30 | perl v5.30.3 |