Mysqlnd_ms Functions
PHP Manual

mysqlnd_ms_get_stats

Returns query distribution and connection statistics

Description

array mysqlnd_ms_get_stats ( void )

Returns an array of statistics collected by the replication and load balancing plugin.

The PHP configuration setting mysqlnd_ms.collect_statistics controls the collection of statistics. The collection of statistics is disabled by default for performance reasons.

The scope of the statistics is the PHP process. Depending on your deployment model a PHP process may handle one or multiple requests.

Statistics are aggregated for all connections and all storage handler. It is not possible to tell how much queries originating from mysqli, PDO_MySQL or mysql API calls have contributed to the aggregated data values.

Parameters

This function has no parameters.

Return Values

Returns NULL if the PHP configuration directive mysqlnd_ms.enable has disabled the plugin. Otherwise, returns array of statistics.

Array of statistics

Statistic Description Version
use_slave

The semantics of this statistic has changed between 1.0.1 - 1.1.0.

The meaning for version 1.0.1 is as follows. Number of statements considered as read-only by the built-in query analyzer. Neither statements which begin with a SQL hint to force use of slave nor statements directed to a slave by an user-defined callback are included. The total number of statements sent to the slaves is use_slave + use_slave_sql_hint + use_slave_callback.

PECL/mysqlnd_ms 1.1.0 introduces a new concept of chained filters. The statistics is now set by the internal load balancing filter. With version 1.1.0 the load balancing filter is always the last in the filter chain, if used. In future versions a load balancing filter may be followed by other filters causing another change in the meaning of the statistic. If, in the future, a load balancing filter is followed by another filter it is no longer guaranteed that the statement, which increments use_slave, will be executed on the slaves.

The meaning for version 1.1.0 is as follows. Number of statements sent to the slaves. Statements directed to a slave by the user filter (an user-defined callback) are not included. The latter are counted by use_slave_callback.

Since 1.0.0.
use_master

The semantics of this statistic has changed between 1.0.1 - 1.1.0.

The meaning for version 1.0.1 is as follows. Number of statements not considered as read-only by the built-in query analyzer. Neither statements which begin with a SQL hint to force use of master nor statements directed to a master by an user-defined callback are included. The total number of statements sent to the master is use_master + use_master_sql_hint + use_master_callback.

PECL/mysqlnd_ms 1.1.0 introduces a new concept of chained filters. The statictics is now set by the internal load balancing filter. With version 1.1.0 the load balancing filter is always the last in the filter chain, if used. In future versions a load balancing filter may be followed by other filters causing another change in the meaning of the statistic. If, in the future, a load balancing filter is followed by another filter it is no longer guaranteed that the statement, which increments use_master, will be executed on the slaves.

The meaning for version 1.1.0 is as follows. Number of statements sent to the masters. Statements directed to a master by the user filter (an user-defined callback) are not included. The latter are counted by use_master_callback.

Since 1.0.0.
use_slave_guess Number of statements the built-in query analyzer recommends sending to a slave because they contain no SQL hint to force use of a certain server. The recommendation may be overruled in the following. It is not guaranteed whether the statement will be executed on a slave or not. This is how often the internal is_select function has guessed that a slave shall be used. Please, see also the user space function mysqlnd_ms_query_is_select. Since 1.1.0.
use_master_guess Number of statements the built-in query analyzer recommends sending to a master because they contain no SQL hint to force use of a certain server. The recommendation may be overruled in the following. It is not guaranteed whether the statement will be executed on a slave or not. This is how often the internal is_select function has guessed that a master shall be used. Please, see also the user space function mysqlnd_ms_query_is_select. Since 1.1.0.
use_slave_sql_hint Number of statements sent to a slave because statement begins with the SQL hint to force use of slave. Since 1.0.0.
use_master_sql_hint Number of statements sent to a master because statement begins with the SQL hint to force use of master. Since 1.0.0.
use_last_used_sql_hint Number of statements sent to server which has run the previous statement, because statement begins with the SQL hint to force use of previously used server. Since 1.0.0.
use_slave_callback Number of statements sent to a slave because an user-defined callback has chosen a slave server for statement execution. Since 1.0.0.
use_master_callback Number of statements sent to a master because an user-defined callback has chosen a master server for statement execution. Since 1.0.0.
non_lazy_connections_slave_success Number of successfully opened slave connections from configurations not using lazy connections. The total number of successfully opened slave connections is non_lazy_connections_slave_success + lazy_connections_slave_success Since 1.0.0.
non_lazy_connections_slave_failure Number of failed slave connection attempts from configurations not using lazy connections. The total number of failed slave connection attempts is non_lazy_connections_slave_failure + lazy_connections_slave_failure Since 1.0.0.
non_lazy_connections_master_success Number of successfully opened master connections from configurations not using lazy connections. The total number of successfully opened master connections is non_lazy_connections_master_success + lazy_connections_master_success Since 1.0.0.
non_lazy_connections_master_failure Number of failed master connection attempts from configurations not using lazy connections. The total number of failed master connection attempts is non_lazy_connections_master_failure + lazy_connections_master_failure Since 1.0.0.
lazy_connections_slave_success Number of successfully opened slave connections from configurations using lazy connections. Since 1.0.0.
lazy_connections_slave_failure Number of failed slave connection attempts from configurations using lazy connections. Since 1.0.0.
lazy_connections_master_success Number of successfully opened master connections from configurations using lazy connections. Since 1.0.0.
lazy_connections_master_failure Number of failed master connection attempts from configurations using lazy connections. Since 1.0.0.
trx_autocommit_on Number of autocommit mode activations via API calls. This figure may be used to monitor activity related to the plugin configuration setting trx_stickiness. If, for example, you want to know if a certain API call invokes the mysqlnd library function trx_autocommit(), which is a requirement for trx_stickiness, you may call the user API function in question and check if the statistic has changed. The statistic is modified only by the plugins internal subclassed trx_autocommit() method. Since 1.0.0.
trx_autocommit_off Number of autocommit mode deactivations via API calls. Since 1.0.0.
trx_master_forced Number of statements redirected to the master while trx_stickiness=master and autocommit mode is disabled. Since 1.0.0.
gtid_autocommit_injections_success Number of successful SQL injections in autocommit mode as part of the plugins client-side global transaction id emulation. Since 1.2.0.
gtid_autocommit_injections_failure Number of failed SQL injections in autocommit mode as part of the plugins client-side global transaction id emulation. Since 1.2.0.
gtid_commit_injections_success Number of successful SQL injections in commit mode as part of the plugins client-side global transaction id emulation. Since 1.2.0.
gtid_commit_injections_failure Number of failed SQL injections in commit mode as part of the plugins client-side global transaction id emulation. Since 1.2.0.
gtid_implicit_commit_injections_success Number of successful SQL injections when implicit commit is detected as part of the plugins client-side global transaction id emulation. Implicit commit happens, for example, when autocommit has been turned off, a query is executed and autocommit is enabled again. In that case, the statement will be committed by the server and SQL to maintain is injected before the autocommit is re-enabled. Another sequence causing an an implicit commit is begin(), query(), begin(). The second call to begin() will implicitly commit the transaction started by the first call to begin(). begin() refers to internal library calls not actual PHP user API calls. Since 1.2.0.
gtid_implicit_commit_injections_failure Number of failed SQL injections when implicit commit is detected as part of the plugins client-side global transaction id emulation. Implicit commit happens, for example, when autocommit has been turned off, a query is executed and autocommit is enabled again. In that case, the statement will be committed by the server and SQL to maintain is injected before the autocommit is re-enabled. Since 1.2.0.
transient_error_retries How often an operation has been retried when a transient error was detected. See also, transient_error plugin configuration file setting. Since 1.6.0.

Examples

Example #1 mysqlnd_ms_get_stats example

<?php
printf("mysqlnd_ms.enable = %d\n", ini_get("mysqlnd_ms.enable"));
printf("mysqlnd_ms.collect_statistics = %d\n", ini_get("mysqlnd_ms.collect_statistics"));
var_dump(mysqlnd_ms_get_stats());
?>

The above example will output:

mysqlnd_ms.enable = 1
mysqlnd_ms.collect_statistics = 1
array(26) {
  ["use_slave"]=>
  string(1) "0"
  ["use_master"]=>
  string(1) "0"
  ["use_slave_guess"]=>
  string(1) "0"
  ["use_master_guess"]=>
  string(1) "0"
  ["use_slave_sql_hint"]=>
  string(1) "0"
  ["use_master_sql_hint"]=>
  string(1) "0"
  ["use_last_used_sql_hint"]=>
  string(1) "0"
  ["use_slave_callback"]=>
  string(1) "0"
  ["use_master_callback"]=>
  string(1) "0"
  ["non_lazy_connections_slave_success"]=>
  string(1) "0"
  ["non_lazy_connections_slave_failure"]=>
  string(1) "0"
  ["non_lazy_connections_master_success"]=>
  string(1) "0"
  ["non_lazy_connections_master_failure"]=>
  string(1) "0"
  ["lazy_connections_slave_success"]=>
  string(1) "0"
  ["lazy_connections_slave_failure"]=>
  string(1) "0"
  ["lazy_connections_master_success"]=>
  string(1) "0"
  ["lazy_connections_master_failure"]=>
  string(1) "0"
  ["trx_autocommit_on"]=>
  string(1) "0"
  ["trx_autocommit_off"]=>
  string(1) "0"
  ["trx_master_forced"]=>
  string(1) "0"
  ["gtid_autocommit_injections_success"]=>
  string(1) "0"
  ["gtid_autocommit_injections_failure"]=>
  string(1) "0"
  ["gtid_commit_injections_success"]=>
  string(1) "0"
  ["gtid_commit_injections_failure"]=>
  string(1) "0"
  ["gtid_implicit_commit_injections_success"]=>
  string(1) "0"
  ["gtid_implicit_commit_injections_failure"]=>
  string(1) "0"
  ["transient_error_retries"]=>
  string(1) "0"
}