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https://dev.mysql.com/doc/refman/8.4/en/locking-functions.html
For example, suppose that you execute these statements: SELECT GET_LOCK('lock1',10); SELECT GET_LOCK('lock2',10); SELECT RELEASE_LOCK('lock2'); SELECT RELEASE_LOCK('lock1'); The second GET_LOCK() acquires a second lock and both RELEASE_LOCK() calls ...While held by one session, other sessions cannot obtain a lock of the same ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-nodes.html
This table contains information on the status of data nodes. For each data node that is running in the cluster, a corresponding row in this table provides the node's node ID, status, and uptime. For nodes that are starting, it also shows the ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-desc.html
The number of bytes shown as Free extent_space is available for storing on-disk column data from the fish table only; for this reason, it is not visible when selecting from the Information Schema FILES table. --ndb-optimized-node-selection ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-drop-index.html
--ndb-optimized-node-selection Command-Line Format --ndb-optimized-node-selection Enable optimizations for selection of nodes for transactions. It is recommended that you use this utility only as an example for writing NDB API applications—see the ...
https://dev.mysql.com/doc/refman/8.4/en/mysqlbinlog.html
--bind-address=ip_address Command-Line Format --bind-address=ip_address On a computer having multiple network interfaces, use this option to select which interface to use for connecting to the MySQL server. --database=db_name, -d db_name ... The ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-functions.html
mysql> SELECT PS_CURRENT_THREAD_ID(); +------------------------+ | PS_CURRENT_THREAD_ID() | +------------------------+ | 52 | +------------------------+ mysql> SELECT PS_THREAD_ID(CONNECTION_ID()); +-------------------------------+ | ... MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-processlist-table.html
The processlist table contains a row for each server process: mysql> SELECT * FROM performance_schema.processlist\G *************************** 1. row *************************** ID: 10 USER: me HOST: localhost:58834 DB: test COMMAND: Query TIME: 0 ... The MySQL process list indicates the operations currently being performed by the set of threads executing within the ...
https://dev.mysql.com/doc/refman/8.4/en/problems-with-null.html
All columns in the following example return NULL: mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL); To search for column values that are NULL, you cannot use an expr = NULL test. The following statement returns no rows, because expr = NULL is ...
https://dev.mysql.com/doc/refman/8.4/en/replication-functions-async-failover.html
Example: SELECT asynchronous_connection_failover_add_managed('channel2', 'GroupReplication', 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa', '127.0.0.1', 3310, '', 80, 60); ... The following functions enable you to add or remove replication source servers ...
https://dev.mysql.com/doc/refman/8.4/en/replication-options-binary-log.html
Only those statements are written to the binary log where the default database (that is, the one selected by USE) is db_name. To specify more than one database, use this option multiple times, once for each database; however, doing so does not cause ... Startup Options Used with Binary Logging System Variables Used with Binary Logging You can use the mysqld options and system variables that are described in this section to affect the operation of the binary log as well as to control which statements are written to the binary ...