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https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-bulk-data-loading.html
When doing bulk inserts into tables with auto-increment columns, set innodb_autoinc_lock_mode to 2 (interleaved) instead of 1 (consecutive). For optimal performance when loading data into an InnoDB FULLTEXT index, follow this set of steps: Define a ... These performance tips supplement the general guidelines for fast inserts in Section 10.2.5.1, “Optimizing INSERT ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-handling-nulls.html
Partitioning in MySQL does nothing to disallow NULL as the value of a partitioning expression, whether it is a column value or the value of a user-supplied expression. If you insert a row into a table partitioned by RANGE such that the column value ...Even though it is permitted to use NULL as the value of an expression that must otherwise yield an integer, it is important to keep in mind that NULL is not a ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-transactions-current-table.html
The events_transactions_current table has these columns: THREAD_ID, EVENT_ID The thread associated with the event and the thread current event number when the event starts. END_EVENT_ID This column is set to NULL when the event starts and updated to ...The table stores one row per thread showing the current status of the thread's most recent monitored transaction event, so there is no system variable for configuring the table ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-object-filtering.html
The OBJECT_TYPE column indicates the type of object to which a row applies. The OBJECT_SCHEMA and OBJECT_NAME columns should contain a literal schema or object name, or '%' to match any name. The ENABLED column indicates whether matching objects are ... The setup_objects table controls whether the Performance Schema monitors particular table and stored program ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-processlist-table.html
This is the same value displayed in the Id column of the SHOW PROCESSLIST statement, displayed in the PROCESSLIST_ID column of the Performance Schema threads table, and returned by the CONNECTION_ID() function within the thread. For system user, ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-quick-start.html
row *************************** Table: setup_consumers Create Table: CREATE TABLE `setup_consumers` ( `NAME` varchar(64) NOT NULL, `ENABLED` enum('YES','NO') NOT NULL, PRIMARY KEY (`NAME`) ) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8mb4 ... This ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-connection-status-table.html
The replication_connection_status table has these columns: CHANNEL_NAME The replication channel which this row is displaying. Issuing RESET BINARY LOGS AND GTIDS or RESET REPLICA resets the values shown in these columns. The ... This table shows the ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-stage-tables.html
No data is provided for the WORK_ESTIMATED column, which displays 0. Bounded progress instrumentation The WORK_COMPLETED and WORK_ESTIMATED columns are both meaningful. The Performance Schema instruments stages, which are steps during the ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-tp-thread-state-table.html
The tp_thread_state table has these columns: TP_GROUP_ID The thread group ID. The xxx_WAIT columns of the tp_thread_group_stats table accumulate counts for each wait type. The value shown in this column is one of CONNECTION_HANDLER_WORKER_THREAD, ...
https://dev.mysql.com/doc/refman/8.4/en/row-subqueries.html
Scalar or column subqueries return a single value or a column of values. A row subquery is a subquery variant that returns a single row and can thus return more than one column value. A row constructor is used for comparisons with subqueries that ...If this row has col3 and col4 values equal to the col1 and col2 values of any rows in t1, the WHERE expression is TRUE and each query returns those t1 ...