Clarify QAN data sources and prepared-statement visibility for MySQL#5600
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michaelcoburn wants to merge 1 commit into
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Clarify QAN data sources and prepared-statement visibility for MySQL#5600michaelcoburn wants to merge 1 commit into
michaelcoburn wants to merge 1 commit into
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Query Analytics reads only from a file-based slow query log or Performance Schema (not the general log or log_output=TABLE). With the Performance Schema source, server-side prepared statements show placeholder examples and no EXPLAIN, because of how upstream MySQL exposes them; the file-based slow query log has real values. Signed-off-by: Michael Coburn <michael.coburn@percona.com>
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What
Adds a short, expectation-setting note so readers recognize why PMM Query Analytics (QAN) may show incomplete data for MySQL prepared-statement workloads.
Why
Server-side prepared statements (used by most application drivers, e.g. JDBC) are exposed by upstream MySQL to Performance Schema with placeholder parameters (
?) rather than literal values. As a result, QAN query examples appear as placeholders and EXPLAIN is unavailable for them. This is upstream MySQL behavior, not a PMM limitation. The note helps users self-diagnose instead of assuming data is missing.Because this page lets users choose the query source, the note also points out that the file-based slow query log records literal values, so it gives fuller examples and EXPLAIN than Performance Schema.
Scope
Documentation only — a single admonition in the "Choose and configure a source" section of
documentation/docs/install-pmm/install-pmm-client/connect-database/mysql/mysql.md. Part of a coordinated set of PRs across pmm, psmysql-docs, pxc-docs, k8sps-docs, and k8spxc-docs.DCO: signed off.