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QAN - increase query length and examples/explain

Is there a way when running PMM with a MySQL node to increase the length of the queries displayed in Query Analytics?

Currently they are getting truncated for our longer queries I am trying to review and they also don't show any information in Examples or Explain.

Answers

  • tiagomotasantostiagomotasantos Percona Staff Role
    edited October 22

    Hi @agrowe,

    You can hover the icon next to the query to see the full query:


    If that doesn't work for you please check the comments in the following feature request to see if it matches your problem: https://jira.percona.com/browse/PMM-6692.

    Thank you for the question and hope this helps!

  • agroweagrowe Current User Role Contributor

    Hi @tiagomotasantos

    Thanks for linking that Jira ticket, it looks to be what I was seeing with the performance schema.

    When hovering over the (i) icon, the full query isn't available which then also causes issues for the examples/explain tabs as they can't show anything.

    According to that ticket, I need to update "max_digest_length" and "performance_schema_max_digest_length" which are the normalised values seen in the query popup.

    To also get the examples column working, it looks like I also need to update "performance_schema_max_sql_text_length", is that correct?

    Are there also any performance considerations to take into account when raising these? the ticket had values of 4000 up from 1024 and also the docs mention a 10:1 ratio of queries to sessions. With only a few hundred sessions at a time, it only looks to add around 8MB total memory requirements.

    Thanks

  • scfscf Current User Role Contributor

    Hi,

    as posted in another thread, the examples/explain tabs worked for me after enabling the events_statements_current and events_statements_history consumers.

    max_digest_length configures the max length for the normalized version (as shown in the screenshot)

    max_sql_text_length configures the max length for the SQL_TEXT column, it is used as example (which is then used for the explain)

    https://forums.percona.com/discussion/comment/57538/#Comment_57538

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