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https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-locks-table.html
To obtain details about the transaction, join this column with the TRX_ID column of the INNODB_TRX table. The INNODB_LOCKS table provides information about each lock that an InnoDB transaction has requested but not yet acquired, and each lock that ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-optimization.html
Applications that monitor databases may make frequent use of INFORMATION_SCHEMA tables. Certain types of queries for INFORMATION_SCHEMA tables can be optimized to execute more quickly. The goal is to minimize file operations (for example, scanning ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-statistics-table.html
The higher the cardinality, the greater the chance that MySQL uses the index when doing joins. The STATISTICS table has these columns: TABLE_CATALOG The name of the catalog to which the table containing the index belongs. TABLE_SCHEMA The name of ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-adaptive-hash.html
Access to the adaptive hash index can sometimes become a source of contention under heavy workloads, such as multiple concurrent joins. The adaptive hash index enables InnoDB to perform more like an in-memory database on systems with appropriate ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-memcached-porting-mysql.html
Consider these aspects of memcached applications when adapting an existing MySQL schema or application to use the daemon_memcached plugin: memcached keys cannot contain spaces or newlines, because these characters are used as separators in the ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html
innodb_thread_sleep_delay Command-Line Format --innodb-thread-sleep-delay=# System Variable innodb_thread_sleep_delay Scope Global Dynamic Yes Type Integer Default Value 10000 Minimum Value 0 Maximum Value 1000000 Unit microseconds Defines how long ... System variables that are true or false can be enabled at server startup by naming them, or disabled by using a --skip- ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-performance-thread_concurrency.html
Since an SQL statement (such as a join) may comprise multiple row operations within InnoDB, InnoDB assigns a specified number of “tickets” that allow a thread to be scheduled repeatedly with minimal overhead. InnoDB uses operating system ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-performance-use_sys_malloc.html
Most workloads, especially those where memory is frequently allocated and released (such as multi-table joins), benefit from using a more highly tuned memory allocator as opposed to the internal, InnoDB-specific memory allocator. When InnoDB was ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-statistics-estimation.html
This technique is especially important for large tables and tables used in joins. Optimizer statistics are not persisted to disk when innodb_stats_persistent=OFF or when individual tables are created or altered with STATS_PERSISTENT=0. Instead, ...
https://dev.mysql.com/doc/refman/5.7/en/insert-on-duplicate.html
References to columns from queries on a join over multiple tables. If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row occurs. If column ...