stmt.schema

The stmt.schema domain sums statement counters from MySQL 8.0 performance_schema.events_statements_summary_by_digest by SCHEMA_NAME. It is opt-in and does not change the default plan.

level:
  collect:
    stmt.schema:
      metrics:
        - count_star
        - sum_timer_wait
        - sum_errors
        - sum_rows_examined
      options:
        include: app,other_app

The default metrics are count_star, sum_timer_wait, sum_errors, sum_rows_examined, and sum_rows_sent. Other supported metrics are sum_lock_time, sum_warnings, sum_rows_affected, sum_created_tmp_tables, sum_created_tmp_disk_tables, sum_select_scan, sum_select_full_join, sum_no_index_used, and sum_no_good_index_used.

All values are cumulative counters. Timer values are in picoseconds. Blip’s delta sink converts cumulative values to changes between samples. The db group contains the statement schema, which does not necessarily identify every table touched by a cross-schema query.

Rows with a null schema or digest are excluded. This includes the digest catch-all row, so the series can undercount when performance_schema_digests_size is exhausted. Monitor the catch-all row separately when completeness matters.

Enable Performance Schema and its statements_digest consumer. The digest table has a fixed size chosen at startup. A full table sends new digests to a null catch-all row, which this collector cannot assign to a schema.