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https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-sys-foreign-cols-table.html
The INNODB_SYS_FOREIGN_COLS table provides status information about the columns of InnoDB foreign keys, equivalent to the information from the SYS_FOREIGN_COLS table in the InnoDB data dictionary. The INNODB_SYS_FOREIGN_COLS table has these ...For ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-locking.html
For example, SELECT c1 FROM t WHERE c1 BETWEEN 10 and 20 FOR UPDATE; prevents other transactions from inserting a value of 15 into column t.c1, whether or not there was already any such value in the column, because the gaps between all existing ...
https://dev.mysql.com/doc/refman/5.7/en/memory-use.html
For each concurrent thread, a table structure, column structures for each column, and a buffer of size 3 * N are allocated (where N is the maximum row length, not counting BLOB columns). A BLOB column requires five to eight bytes plus the length of ... MySQL allocates buffers and caches to improve performance of database ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-mutex-instances-table.html
The mutex_instances table has these columns: NAME The instrument name associated with the mutex. The OBJECT_INSTANCE_BEGIN column is a property that uniquely identifies the mutex. When a thread attempts to lock a mutex, the events_waits_current ...
https://dev.mysql.com/doc/refman/5.7/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/5.7/en/performance-schema-replication-applier-status-by-coordinator-table.html
The replication_applier_status_by_coordinator table has these columns: CHANNEL_NAME The replication channel which this row is displaying. Issuing RESET MASTER or RESET SLAVE resets the values shown in these columns. All error codes and messages ...
https://dev.mysql.com/doc/refman/5.7/en/primary-key-optimization.html
The primary key for a table represents the column or set of columns that you use in your most vital queries. With the InnoDB storage engine, the table data is physically organized to do ultra-fast lookups and sorts based on the primary key column ...Query performance benefits from the NOT NULL optimization, because it cannot include any NULL ...
https://dev.mysql.com/doc/refman/5.7/en/replication-features-max-allowed-packet.html
If you are replicating large column values (such as might be found in TEXT or BLOB columns) and max_allowed_packet is too small on the source, the source fails with an error, and the replica shuts down the replication I/O thread. Row-based ...
https://dev.mysql.com/doc/refman/5.7/en/type-conversion.html
If one of the arguments is a TIMESTAMP or DATETIME column and the other argument is a constant, the constant is converted to a timestamp before the comparison is performed. If str_col is an indexed string column, the index cannot be used when ...
https://dev.mysql.com/doc/refman/5.7/en/alter-table-partition-operations.html
To upgrade a KEY partitioned table that was created in MySQL 5.1, first execute SHOW CREATE TABLE and note the exact columns and number of partitions shown. Now execute an ALTER TABLE statement using exactly the same column list and number of ...