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https://dev.mysql.com/doc/refman/8.4/en/drop-index.html
algorithm_option: ALGORITHM [=] {DEFAULT | INPLACE | COPY} lock_option: LOCK [=] {DEFAULT | NONE | SHARED | EXCLUSIVE} DROP INDEX drops the index named index_name from the table tbl_name. The table is not locked against access from other NDB Cluster ...This statement is mapped to an ALTER TABLE statement to drop the ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-system-variables.html
STOP GROUP_REPLICATION does not complete until either the situation is resolved (for example, by the lock being released), or the component timeout expires and the modules are shut down regardless of their status. Any existing members that are not ... This section lists the system variables that are specific to the Group Replication ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-monitor-types.html
There are two types of InnoDB monitor: The standard InnoDB Monitor displays the following types of information: Work done by the main background thread Semaphore waits Data about the most recent foreign key and deadlock errors Lock waits for ...
https://dev.mysql.com/doc/refman/8.4/en/memory-storage-engine.html
NDB Cluster offers the same features as the MEMORY engine with higher performance levels, and provides additional features not available with MEMORY: Row-level locking and multiple-thread operation for low contention between clients. Performance ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-option-tables.html
ndb-log-exclusive-reads: Log primary key reads with exclusive locks; allow conflict resolution based on read conflicts. Ndb_api_wait_exec_complete_count: Number of times thread has been blocked while waiting for operation execution to complete by ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-replication-conflict-resolution.html
This requires exclusive read locks obtained by setting ndb_log_exclusive_reads equal to 1 on the replica. READ_ROW operations are user-initiated read tracking operations defined with exclusive row locks. Acquiring exclusive read locks in this way ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-thread-states.html
Waiting for allowed to take ndbcluster global schema lock The thread is waiting for permission to take a global schema lock. Waiting for first event from ndbcluster Waiting for ndbcluster binlog update to reach current position Waiting for ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-queries-myisam.html
Try to avoid complex SELECT queries on MyISAM tables that are updated frequently, to avoid problems with table locking that occur due to contention between readers and writers. MyISAM supports concurrent inserts: If a table has no free blocks in the ... Some general tips for speeding up queries on MyISAM tables: To help MySQL better optimize queries, use ANALYZE TABLE or run myisamchk --analyze on a table after it has been loaded with ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-setup-instruments-table.html
row *************************** NAME: wait/synch/mutex/pfs/LOCK_pfs_share_list ENABLED: NO TIMED: NO PROPERTIES: singleton FLAGS: NULL VOLATILITY: 1 DOCUMENTATION: Components can provide their own performance_schema tables. When an instrument is ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-tp-thread-group-stats-table.html
ROW_LOCK_WAITS The number of THD_WAIT_ROW_LOCK waits for release of a row lock by another transaction. GLOBAL_LOCK_WAITS The number of THD_WAIT_GLOBAL_LOCK waits for a global lock to be released. META_DATA_LOCK_WAITS The number of ...The ...