Performance Schema events_statements_history Table
The events_statements_history table by default contains the ten most recent completed statement events per thread. This number can be adjusted by setting the performance_schema_events_statements_history_size system variable when the server starts up.
The table structure is identical to the events_statements_current table structure, and contains the following columns:
The table contains the following columns:
| Column | Description |
|---|---|
THREAD_ID | Thread associated with the event. Together with EVENT_ID uniquely identifies the row. |
EVENT_ID | Thread's current event number at the start of the event. Together with THREAD_ID uniquely identifies the row. |
END_EVENT_ID | NULL when the event starts, set to the thread's current event number at the end of the event. |
EVENT_NAME | Event instrument name and a NAME from the setup_instruments table |
SOURCE | Name and line number of the source file containing the instrumented code that produced the event. |
TIMER_START | Value in picoseconds when the event timing started or NULL if timing is not collected. |
TIMER_END | Value in picoseconds when the event timing ended, or NULL if timing is not collected. |
TIMER_WAIT | Value in picoseconds of the event's duration or NULL if timing is not collected. |
LOCK_TIME | Time in picoseconds spent waiting for locks. The time is calculated in microseconds but stored in picoseconds for compatibility with other timings. |
SQL_TEXT | The SQL statement, or NULL if the command is not associated with an SQL statement. |
DIGEST | Statement digest. |
DIGEST_TEXT | Statement digest text. |
CURRENT_SCHEMA | Statement's default database for the statement, or NULL if there was none. |
OBJECT_SCHEMA | Reserved, currently NULL |
OBJECT_NAME | Reserved, currently NULL |
OBJECT_TYPE | Reserved, currently NULL |
OBJECT_INSTANCE_BEGIN | Address in memory of the statement object. |
MYSQL_ERRNO | Error code. See MariaDB Error Codes for a full list. |
RETURNED_SQLSTATE | The SQLSTATE value. |
MESSAGE_TEXT | Statement error message. See MariaDB Error Codes. |
ERRORS | 0 if SQLSTATE signifies completion (starting with 00) or warning (01), otherwise 1. |
WARNINGS | Number of warnings from the diagnostics area. |
ROWS_AFFECTED | Number of rows affected the statement affected. |
ROWS_SENT | Number of rows returned. |
ROWS_EXAMINED | Number of rows read during the statement's execution. |
CREATED_TMP_DISK_TABLES | Number of on-disk temp tables created by the statement. |
CREATED_TMP_TABLES | Number of temp tables created by the statement. |
SELECT_FULL_JOIN | Number of joins performed by the statement which did not use an index. |
SELECT_FULL_RANGE_JOIN | Number of joins performed by the statement which used a range search of the first table. |
SELECT_RANGE | Number of joins performed by the statement which used a range of the first table. |
SELECT_RANGE_CHECK | Number of joins without keys performed by the statement that check for key usage after each row. |
SELECT_SCAN | Number of joins performed by the statement which used a full scan of the first table. |
SORT_MERGE_PASSES | Number of merge passes by the sort algorithm performed by the statement. If too high, you may need to increase the sort_buffer_size. |
SORT_RANGE | Number of sorts performed by the statement which used a range. |
SORT_ROWS | Number of rows sorted by the statement. |
SORT_SCAN | Number of sorts performed by the statement which used a full table scan. |
NO_INDEX_USED | 0 if the statement performed a table scan with an index, 1 if without an index. |
NO_GOOD_INDEX_USED | 0 if a good index was found for the statement, 1 if no good index was found. See the Range checked for each record description in the EXPLAIN article. |
NESTING_EVENT_ID | Reserved, currently NULL. |
NESTING_EVENT_TYPE | Reserved, currently NULL. |
It is possible to empty this table with a TRUNCATE TABLE statement.
events_statements_current and events_statements_history_long are related tables.
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