# SQL statistics for MariaDB and MySQL
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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](#USER_PerfInsights.UsingDashboard.AnalyzeDBLoad.AdditionalMetrics.MySQL.truncation)
+ [Per-second statistics for MariaDB and MySQL](#USER_PerfInsights.UsingDashboard.AnalyzeDBLoad.AdditionalMetrics.MySQL.per-second)
+ [Per-call statistics for MariaDB and MySQL](#USER_PerfInsights.UsingDashboard.AnalyzeDBLoad.AdditionalMetrics.MySQL.truncation.per-call)
+ [Primary statistics for MariaDB and MySQL](#USER_PerfInsights.UsingDashboard.AnalyzeDBLoad.AdditionalMetrics.MySQL.primary)

## Digest statistics for MariaDB and MySQL
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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_schema` parameter must be set to `0` and the **Source** must not be set to `user`. 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](USER_PerfInsights.EnableMySQL.md).

In the AWS CLI, check the source of a parameter value by running the [describe-db-parameters](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameters.html) command.

## Per-second statistics for MariaDB and MySQL
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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
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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) | 

## Primary statistics for MariaDB and MySQL
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The following SQL statistics are available for MariaDB and MySQL DB instances.


| Metric | Unit | 
| --- | --- | 
| db.sql\_tokenized.stats.count\_star | Calls | 
| db.sql\_tokenized.stats.sum\_timer\_wait | Wait time (in ms) | 
| db.sql\_tokenized.stats.sum\_select\_full\_join | Select full join | 
| db.sql\_tokenized.stats.sum\_select\_range\_check | Select range checks | 
| db.sql\_tokenized.stats.sum\_select\_scan | Select scans | 
| db.sql\_tokenized.stats.sum\_sort\_merge\_passes | Sort merge passes | 
| db.sql\_tokenized.stats.sum\_sort\_scan | Sort scans | 
| db.sql\_tokenized.stats.sum\_sort\_range | Sort ranges | 
| db.sql\_tokenized.stats.sum\_sort\_rows | Sort rows | 
| db.sql\_tokenized.stats.sum\_rows\_affected | Rows affected | 
| db.sql\_tokenized.stats.sum\_rows\_examined | Rows examined | 
| db.sql\_tokenized.stats.sum\_rows\_sent | Rows sent | 
| db.sql\_tokenized.stats.sum\_created\_tmp\_disk\_tables | Created temporary disk tables | 
| db.sql\_tokenized.stats.sum\_created\_tmp\_tables | Created temporary tables | 
| db.sql\_tokenized.stats.sum\_lock\_time | Lock time (in ms) |