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26.4.7 Pre-Filtering by Consumer

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The setup_consumers table lists the available consumer types and which are enabled:

  1. mysql> SELECT * FROM performance_schema.setup_consumers;
  2. +----------------------------------+---------+
  3. | NAME                             | ENABLED |
  4. +----------------------------------+---------+
  5. | events_stages_current            | NO      |
  6. | events_stages_history            | NO      |
  7. | events_stages_history_long       | NO      |
  8. | events_statements_current        | YES     |
  9. | events_statements_history        | YES     |
  10. | events_statements_history_long   | NO      |
  11. | events_transactions_current      | YES     |
  12. | events_transactions_history      | YES     |
  13. | events_transactions_history_long | NO      |
  14. | events_waits_current             | NO      |
  15. | events_waits_history             | NO      |
  16. | events_waits_history_long        | NO      |
  17. | global_instrumentation           | YES     |
  18. | thread_instrumentation           | YES     |
  19. | statements_digest                | YES     |
  20. +----------------------------------+---------+

Modify the setup_consumers table to affect pre-filtering at the consumer stage and determine the destinations to which events are sent. To enable or disable a consumer, set its ENABLED value to YES or NO.

Modifications to the setup_consumers table affect monitoring immediately.

If you disable a consumer, the server does not spend time maintaining destinations for that consumer. For example, if you do not care about historical event information, disable the history consumers:

  1. UPDATE performance_schema.setup_consumers
  2. SET ENABLED = 'NO'
  3. WHERE NAME LIKE '%history%';

The consumer settings in the setup_consumers table form a hierarchy from higher levels to lower. The following principles apply:

  • Destinations associated with a consumer receive no events unless the Performance Schema checks the consumer and the consumer is enabled.

  • A consumer is checked only if all consumers it depends on (if any) are enabled.

  • If a consumer is not checked, or is checked but is disabled, other consumers that depend on it are not checked.

  • Dependent consumers may have their own dependent consumers.

  • If an event would not be sent to any destination, the Performance Schema does not produce it.

The following lists describe the available consumer values. For discussion of several representative consumer configurations and their effect on instrumentation, see Section 26.4.8, “Example Consumer Configurations”.

Global and Thread Consumers

  • global_instrumentation is the highest level consumer. If global_instrumentation is NO, it disables global instrumentation. All other settings are lower level and are not checked; it does not matter what they are set to. No global or per thread information is maintained and no individual events are collected in the current-events or event-history tables. If global_instrumentation is YES, the Performance Schema maintains information for global states and also checks the thread_instrumentation consumer.

  • thread_instrumentation is checked only if global_instrumentation is YES. Otherwise, if thread_instrumentation is NO, it disables thread-specific instrumentation and all lower-level settings are ignored. No information is maintained per thread and no individual events are collected in the current-events or event-history tables. If thread_instrumentation is YES, the Performance Schema maintains thread-specific information and also checks events_xxx_current consumers.

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Wait Event Consumers

These consumers require both global_instrumentation and thread_instrumentation to be YES or they are not checked. If checked, they act as follows:

  • events_waits_current, if NO, disables collection of individual wait events in the events_waits_current table. If YES, it enables wait event collection and the Performance Schema checks the events_waits_history and events_waits_history_long consumers.

  • events_waits_history is not checked if event_waits_current is NO. Otherwise, an events_waits_history value of NO or YES disables or enables collection of wait events in the events_waits_history table.

  • events_waits_history_long is not checked if event_waits_current is NO. Otherwise, an events_waits_history_long value of NO or YES disables or enables collection of wait events in the events_waits_history_long table.

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Stage Event Consumers

These consumers require both global_instrumentation and thread_instrumentation to be YES or they are not checked. If checked, they act as follows:

  • events_stages_current, if NO, disables collection of individual stage events in the events_stages_current table. If YES, it enables stage event collection and the Performance Schema checks the events_stages_history and events_stages_history_long consumers.

  • events_stages_history is not checked if event_stages_current is NO. Otherwise, an events_stages_history value of NO or YES disables or enables collection of stage events in the events_stages_history table.

  • events_stages_history_long is not checked if event_stages_current is NO. Otherwise, an events_stages_history_long value of NO or YES disables or enables collection of stage events in the events_stages_history_long table.

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Statement Event Consumers

These consumers require both global_instrumentation and thread_instrumentation to be YES or they are not checked. If checked, they act as follows:

  • events_statements_current, if NO, disables collection of individual statement events in the events_statements_current table. If YES, it enables statement event collection and the Performance Schema checks the events_statements_history and events_statements_history_long consumers.

  • events_statements_history is not checked if events_statements_current is NO. Otherwise, an events_statements_history value of NO or YES disables or enables collection of statement events in the events_statements_history table.

  • events_statements_history_long is not checked if events_statements_current is NO. Otherwise, an events_statements_history_long value of NO or YES disables or enables collection of statement events in the events_statements_history_long table.

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Transaction Event Consumers

These consumers require both global_instrumentation and thread_instrumentation to be YES or they are not checked. If checked, they act as follows:

  • events_transactions_current, if NO, disables collection of individual transaction events in the events_transactions_current table. If YES, it enables transaction event collection and the Performance Schema checks the events_transactions_history and events_transactions_history_long consumers.

  • events_transactions_history is not checked if events_transactions_current is NO. Otherwise, an events_transactions_history value of NO or YES disables or enables collection of transaction events in the events_transactions_history table.

  • events_transactions_history_long is not checked if events_transactions_current is NO. Otherwise, an events_transactions_history_long value of NO or YES disables or enables collection of transaction events in the events_transactions_history_long table.

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Statement Digest Consumer

The statements_digest consumer requires global_instrumentation to be YES or it is not checked. There is no dependency on the statement event consumers, so you can obtain statistics per digest without having to collect statistics in events_statements_current, which is advantageous in terms of overhead. Conversely, you can get detailed statements in events_statements_current without digests (the DIGEST and DIGEST_TEXT columns will be NULL).

For more information about statement digesting, see Section 26.10, “Performance Schema Statement Digests and Sampling”.


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