27.4.4.2 The diagnostics() Procedure

Creates a report of the current server status for diagnostic purposes.

This procedure disables binary logging during its execution by manipulating the session value of the sql_log_bin system variable. That is a restricted operation, so the procedure requires privileges sufficient to set restricted session variables. See Section 5.1.9.1, “System Variable Privileges”.

Data collected for diagnostics() includes this information:

Information from the metrics view (see Section 27.4.3.21, “The metrics View”)
Information from other relevant sys schema views, such as the one that detemines queries in the 95th percentile
Information from the ndbinfo schema, if the MySQL server is part of NDB Cluster
Replication status (both master and slave)

Some of the sys schema views are calculated as initial (optional), overall, and delta values:

The initial view is the content of the view at the start of the diagnostics() procedure. This output is the same as the start values used for the delta view. The initial view is included if the diagnostics.include_raw configuration option is ON.
The overall view is the content of the view at the end of the diagnostics() procedure. This output is the same as the end values used for the delta view. The overall view is always included.
The delta view is the difference from the beginning to the end of procedure execution. The minimum and maximum values are the minimum and maximum values from the end view, respectively. They do not necessarily reflect the minimum and maximum values in the monitored period. Except for the metrics view, the delta is calculated only between the first and last outputs.

Parameters

in_max_runtime INT UNSIGNED: The maximum data collection time in seconds. Use NULL to collect data for the default of 60 seconds. Otherwise, use a value greater than 0.
in_interval INT UNSIGNED: The sleep time between data collections in seconds. Use NULL to sleep for the default of 30 seconds. Otherwise, use a value greater than 0.
in_auto_config ENUM('current', 'medium', 'full'): The Performance Schema configuration to use. Permitted values are:
- current: Use the current instrument and consumer settings.
- medium: Enable some instruments and consumers.
- full: Enable all instruments and consumers.
Note

The more instruments and consumers enabled, the more impact on MySQL server performance. Be careful with the medium setting and especially the full setting, which has a large performance impact.

Use of the medium or full setting requires the SUPER privilege.
If a setting other than current is chosen, the current settings are restored at the end of the procedure.

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Configuration Options

diagnostics() operation can be modified using the following configuration options or their corresponding user-defined variables (see Section 27.4.2.1, “The sys_config Table”):

debug, @sys.debug
If this option is ON, produce debugging output. The default is OFF.
diagnostics.allow_i_s_tables, @sys.diagnostics.allow_i_s_tables
If this option is ON, the diagnostics() procedure is permitted to perform table scans on the INFORMATION_SCHEMA.TABLES table. This can be expensive if there are many tables. The default is OFF.
diagnostics.include_raw, @sys.diagnostics.include_raw
If this option is ON, the diagnostics() procedure output includes the raw output from querying the metrics view. The default is OFF.
statement_truncate_len, @sys.statement_truncate_len
The maximum length of statements returned by the format_statement() function. Longer statements are truncated to this length. The default is 64.

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Example

Create a diagnostics report that starts an iteration every 30 seconds and runs for at most 120 seconds using the current Performance Schema settings:

mysql> CALL sys.diagnostics(120, 30, 'current');

To capture the output from the diagnostics() procedure in a file as it runs, use the mysql client tee filename and notee commands (see Section 4.5.1.2, “mysql Client Commands”):

mysql> tee diag.out;
mysql> CALL sys.diagnostics(120, 30, 'current');
mysql> notee;

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Document created the 26/06/2006, last modified the 26/10/2018
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References

Manuel MySQL : https://dev.mysql.com/

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