# Performance Schema events\_statements\_summary\_by\_digest Table
The [Performance Schema digest](/docs/server/reference/system-tables/performance-schema/performance-schema-digests.md) is a hashed, normalized form of a statement with the specific data values removed. It allows statistics to be gathered for similar kinds of statements.
The [Performance Schema](/docs/server/reference/system-tables/performance-schema.md) `events_statements_summary_by_digest` table records statement events summarized by schema and digest. It contains the following columns:
| Column | Description |
| ------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| SCHEMA NAME | Database name. Records are summarised together with DIGEST. |
| DIGEST | [Performance Schema digest](/docs/server/reference/system-tables/performance-schema/performance-schema-digests.md). Records are summarised together with SCHEMA NAME. |
| DIGEST TEXT | The unhashed form of the digest. |
| COUNT\_STAR | Number of summarized events |
| SUM\_TIMER\_WAIT | Total wait time of the summarized events that are timed. |
| MIN\_TIMER\_WAIT | Minimum wait time of the summarized events that are timed. |
| AVG\_TIMER\_WAIT | Average wait time of the summarized events that are timed. |
| MAX\_TIMER\_WAIT | Maximum wait time of the summarized events that are timed. |
| SUM\_LOCK\_TIME | Sum of the LOCK\_TIME column in the events\_statements\_current table. |
| SUM\_ERRORS | Sum of the ERRORS column in the events\_statements\_current table. |
| SUM\_WARNINGS | Sum of the WARNINGS column in the events\_statements\_current table. |
| SUM\_ROWS\_AFFECTED | Sum of the ROWS\_AFFECTED column in the events\_statements\_current table. |
| SUM\_ROWS\_SENT | Sum of the ROWS\_SENT column in the events\_statements\_current table. |
| SUM\_ROWS\_EXAMINED | Sum of the ROWS\_EXAMINED column in the events\_statements\_current table. |
| SUM\_CREATED\_TMP\_DISK\_TABLES | Sum of the CREATED\_TMP\_DISK\_TABLES column in the events\_statements\_current table. |
| SUM\_CREATED\_TMP\_TABLES | Sum of the CREATED\_TMP\_TABLES column in the events\_statements\_current table. |
| SUM\_SELECT\_FULL\_JOIN | Sum of the SELECT\_FULL\_JOIN column in the events\_statements\_current table. |
| SUM\_SELECT\_FULL\_RANGE\_JOIN | Sum of the SELECT\_FULL\_RANGE\_JOIN column in the events\_statements\_current table. |
| SUM\_SELECT\_RANGE | Sum of the SELECT\_RANGE column in the events\_statements\_current table. |
| SUM\_SELECT\_RANGE\_CHECK | Sum of the SELECT\_RANGE\_CHECK column in the events\_statements\_current table. |
| SUM\_SELECT\_SCAN | Sum of the SELECT\_SCAN column in the events\_statements\_current table. |
| SUM\_SORT\_MERGE\_PASSES | Sum of the SORT\_MERGE\_PASSES column in the events\_statements\_current table. |
| SUM\_SORT\_RANGE | Sum of the SORT\_RANGE column in the events\_statements\_current table. |
| SUM\_SORT\_ROWS | Sum of the SORT\_ROWS column in the events\_statements\_current table. |
| SUM\_SORT\_SCAN | Sum of the SORT\_SCAN column in the events\_statements\_current table. |
| SUM\_NO\_INDEX\_USED | Sum of the NO\_INDEX\_USED column in the events\_statements\_current table. |
| SUM\_NO\_GOOD\_INDEX\_USED | Sum of the NO\_GOOD\_INDEX\_USED column in the events\_statements\_current table. |
| FIRST\_SEEN | Time at which the digest was first seen. |
| LAST\_SEEN | Time at which the digest was most recently seen. |
The `*_TIMER_WAIT` columns only calculate results for timed events, as non-timed events have a `NULL` wait time.
The `events_statements_summary_by_digest` table is limited in size by the [performance\_schema\_digests\_size](/docs/server/reference/system-tables/performance-schema/performance-schema-system-variables.md#performance_schema_digests_size) system variable. Once the limit has been reached and the table is full, all entries are aggregated in a row with a `NULL` digest. The `COUNT_STAR` value of this `NULL` row indicates how many digests are recorded in the row and therefore gives an indication of whether `performance_schema_digests_size` should be increased to provide more accurate statistics.
*This page is licensed: CC BY-SA / Gnu FDL*
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