The Ultimate Guide to High Availability with MariaDB

Performance Schema events_statements_history_long Table

The events_statements_history_long table by default contains the ten thousand most recent completed statement events. This number can be adjusted by setting the performance_schema_events_statements_history_long_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:

ColumnDescription
THREAD_IDThread associated with the event. Together with EVENT_ID uniquely identifies the row.
EVENT_IDThread's current event number at the start of the event. Together with THREAD_ID uniquely identifies the row.
END_EVENT_IDNULL when the event starts, set to the thread's current event number at the end of the event.
EVENT_NAMEEvent instrument name and a NAME from the setup_instruments table
SOURCEName and line number of the source file containing the instrumented code that produced the event.
TIMER_STARTValue in picoseconds when the event timing started or NULL if timing is not collected.
TIMER_ENDValue in picoseconds when the event timing ended, or NULL if timing is not collected.
TIMER_WAITValue in picoseconds of the event's duration or NULL if timing is not collected.
LOCK_TIMETime in picoseconds spent waiting for locks. The time is calculated in microseconds but stored in picoseconds for compatibility with other timings.
SQL_TEXTThe SQL statement, or NULL if the command is not associated with an SQL statement.
DIGESTStatement digest.
DIGEST_TEXTStatement digest text.
CURRENT_SCHEMAStatement's default database for the statement, or NULL if there was none.
OBJECT_SCHEMAReserved, currently NULL
OBJECT_NAMEReserved, currently NULL
OBJECT_TYPEReserved, currently NULL
OBJECT_INSTANCE_BEGINAddress in memory of the statement object.
MYSQL_ERRNOError code. See MariaDB Error Codes for a full list.
RETURNED_SQLSTATEThe SQLSTATE value.
MESSAGE_TEXTStatement error message. See MariaDB Error Codes.
ERRORS0 if SQLSTATE signifies completion (starting with 00) or warning (01), otherwise 1.
WARNINGSNumber of warnings from the diagnostics area.
ROWS_AFFECTEDNumber of rows affected the statement affected.
ROWS_SENTNumber of rows returned.
ROWS_EXAMINEDNumber of rows read during the statement's execution.
CREATED_TMP_DISK_TABLESNumber of on-disk temp tables created by the statement.
CREATED_TMP_TABLESNumber of temp tables created by the statement.
SELECT_FULL_JOINNumber of joins performed by the statement which did not use an index.
SELECT_FULL_RANGE_JOINNumber of joins performed by the statement which used a range search of the first table.
SELECT_RANGENumber of joins performed by the statement which used a range of the first table.
SELECT_RANGE_CHECKNumber of joins without keys performed by the statement that check for key usage after each row.
SELECT_SCANNumber of joins performed by the statement which used a full scan of the first table.
SORT_MERGE_PASSESNumber of merge passes by the sort algorithm performed by the statement. If too high, you may need to increase the sort_buffer_size.
SORT_RANGENumber of sorts performed by the statement which used a range.
SORT_ROWSNumber of rows sorted by the statement.
SORT_SCANNumber of sorts performed by the statement which used a full table scan.
NO_INDEX_USED0 if the statement performed a table scan with an index, 1 if without an index.
NO_GOOD_INDEX_USED0 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_IDReserved, currently NULL.
NESTING_EVENT_TYPEReserved, currently NULL.

It is possible to empty this table with a TRUNCATE TABLE statement.

events_statements_current and events_statements_history are related tables.

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