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https://dev.mysql.com/doc/refman/8.0/en/innodb-next-key-locking.html
To prevent phantoms, InnoDB uses an algorithm called next-key locking that combines index-row locking with gap locking. The so-called phantom problem occurs within a transaction when the same query produces different sets of rows at different times. For example, if a SELECT is executed twice, but returns a row the second time that was not returned the first time, the row is a “phantom” ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl-single-multi.html
Operations for which you specify ALGORITHM=COPY or old_alter_table=1, to force the table-copying behavior if needed for precise backward-compatibility in specialized scenarios. Before the introduction of online DDL, it was common practice to ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-performance-compression-oltp.html
This option is enabled by default to prevent corruption that could occur if a different version of the zlib compression algorithm is used during recovery. Traditionally, the InnoDB compression feature was recommended primarily for read-only or ...
https://dev.mysql.com/doc/refman/8.0/en/keyring-key-types.html
MySQL Keyring supports keys of different types (encryption algorithms) and lengths: The available key types depend on which keyring plugin is installed. The permitted key lengths are subject to multiple factors: General keyring loadable-function ...
https://dev.mysql.com/doc/refman/8.0/en/mathematical-functions.html
ABS(X) Returns the absolute value of X, or NULL if X is NULL. An implication of this is that ABS(-9223372036854775808) produces an error because the result cannot be stored in a signed BIGINT value. mysql> SELECT ABS(2); -> 2 mysql> SELECT ABS(-32); ...
https://dev.mysql.com/doc/refman/8.0/en/memory-use.html
For efficiency of cache management, the buffer pool is implemented as a linked list of pages; data that is rarely used is aged out of the cache, using a variation of the LRU algorithm. MySQL allocates buffers and caches to improve performance of ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-backup-using-management-client.html
Before starting a backup, make sure that the cluster is properly configured for performing one. If an existing backup_id value is used, the backup fails with the error Backup failed: file already exists. If used, the backup_id must follow ...
https://dev.mysql.com/doc/refman/8.0/en/nonpersistible-system-variables.html
SET PERSIST and SET PERSIST_ONLY enable global system variables to be persisted to the mysqld-auto.cnf option file in the data directory (see Section 15.7.6.1, “SET Syntax for Variable Assignment”). However, not all system variables can be ...
https://dev.mysql.com/doc/refman/8.0/en/performance-schema-tp-thread-group-state-table.html
ALGORITHM The value of the thread_pool_algorithm system variable for the thread group. Note The Performance Schema table described here is available as of MySQL 8.0.14. Prior to MySQL 8.0.14, use the corresponding INFORMATION_SCHEMA table instead; ...
https://dev.mysql.com/doc/refman/8.0/en/replica-logs-status.html
A replica server creates two replication metadata repositories, the connection metadata repository and the applier metadata repository. If binary log file position based replication is in use, when the replica restarts, it reads the two ...