SQL statistics for MariaDB and MySQL
MariaDB and MySQL collect SQL statistics only at the digest level. No statistics are shown at the statement level.
Topics
Digest statistics for MariaDB and MySQL
Performance Insights collects SQL digest statistics from the events_statements_summary_by_digest table. The
events_statements_summary_by_digest table is managed by your database.
The digest table doesn't have an eviction policy. When the table is full, the AWS Management Console shows the following message:
Performance Insights is unable to collect SQL Digest statistics on new queries because the table events_statements_summary_by_digest is full. Please truncate events_statements_summary_by_digest table to clear the issue. Check the User Guide for more details.
In this situation, MariaDB and MySQL don't track SQL queries. To address this issue, Performance Insights automatically truncates the digest table when both of the following conditions are met:
-
The table is full.
-
Performance Insights manages the Performance Schema automatically.
For automatic management, the
performance_schemaparameter must be set to0and the Source must not be set touser. If Performance Insights isn't managing the Performance Schema automatically, see Overview of the Performance Schema for Performance Insights on Amazon RDS for MariaDB or MySQL.
In the AWS CLI, check the source of a parameter value by running the describe-db-parameters command.
Per-second statistics for MariaDB and MySQL
The following SQL statistics are available for MariaDB and MySQL DB instances.
| Metric | Unit |
|---|---|
| db.sql_tokenized.stats.count_star_per_sec | Calls per second |
| db.sql_tokenized.stats.sum_timer_wait_per_sec | Average latency per second (in ms)) |
| db.sql_tokenized.stats.sum_select_full_join_per_sec | Select full join per second |
| db.sql_tokenized.stats.sum_select_range_check_per_sec | Select range check per second |
| db.sql_tokenized.stats.sum_select_scan_per_sec | Select scan per second |
| db.sql_tokenized.stats.sum_sort_merge_passes_per_sec | Sort merge passes per second |
| db.sql_tokenized.stats.sum_sort_scan_per_sec | Sort scans per second |
| db.sql_tokenized.stats.sum_sort_range_per_sec | Sort ranges per second |
| db.sql_tokenized.stats.sum_sort_rows_per_sec | Sort rows per second |
| db.sql_tokenized.stats.sum_rows_affected_per_sec | Rows affected per second |
| db.sql_tokenized.stats.sum_rows_examined_per_sec | Rows examined per second |
| db.sql_tokenized.stats.sum_rows_sent_per_sec | Rows sent per second |
| db.sql_tokenized.stats.sum_created_tmp_disk_tables_per_sec | Created temporary disk tables per second |
| db.sql_tokenized.stats.sum_created_tmp_tables_per_sec | Created temporary tables per second |
| db.sql_tokenized.stats.sum_lock_time_per_sec | Lock time per second (in ms) |
Per-call statistics for MariaDB and MySQL
The following metrics provide per call statistics for a SQL statement.
| Metric | Unit |
|---|---|
| db.sql_tokenized.stats.sum_timer_wait_per_call | Average latency per call (in ms) |
| db.sql_tokenized.stats.sum_select_full_join_per_call | Select full joins per call |
| db.sql_tokenized.stats.sum_select_range_check_per_call | Select range check per call |
| db.sql_tokenized.stats.sum_select_scan_per_call | Select scans per call |
| db.sql_tokenized.stats.sum_sort_merge_passes_per_call | Sort merge passes per call |
| db.sql_tokenized.stats.sum_sort_scan_per_call | Sort scans per call |
| db.sql_tokenized.stats.sum_sort_range_per_call | Sort ranges per call |
| db.sql_tokenized.stats.sum_sort_rows_per_call | Sort rows per call |
| db.sql_tokenized.stats.sum_rows_affected_per_call | Rows affected per call |
| db.sql_tokenized.stats.sum_rows_examined_per_call | Rows examined per call |
| db.sql_tokenized.stats.sum_rows_sent_per_call | Rows sent per call |
| db.sql_tokenized.stats.sum_created_tmp_disk_tables_per_call | Created temporary disk tables per call |
| db.sql_tokenized.stats.sum_created_tmp_tables_per_call | Created temporary tables per call |
| db.sql_tokenized.stats.sum_lock_time_per_call | Lock time per call (in ms) |
