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https://dev.mysql.com/doc/refman/8.4/en/innodb-performance-spin_lock_polling.html
InnoDB mutexes and rw-locks are typically reserved for short intervals. On a multi-core system, it can be more efficient for a thread to continuously check if it can acquire a mutex or rw-lock for a period of time before it sleeps. If the mutex or ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-performance-thread_concurrency.html
InnoDB uses operating system threads to process requests from user transactions. (Transactions may issue many requests to InnoDB before they commit or roll back.) On modern operating systems and servers with multi-core processors, where context ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-purge-configuration.html
InnoDB does not physically remove a row from the database immediately when you delete it with an SQL statement. A row and its index records are only physically removed when InnoDB discards the undo log record written for the deletion. This removal ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-read-only-instance.html
You can query InnoDB tables where the MySQL data directory is on read-only media by enabling the --innodb-read-only configuration option at server startup. How to Enable To prepare an instance for read-only operation, make sure all the necessary ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-redo-log-buffer.html
The log buffer is the memory area that holds data to be written to the log files on disk. The contents of the log buffer are periodically flushed to disk. A large log buffer enables large transactions to run without the need to write redo log data ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-temporary-tablespace.html
A range of 400 thousand space IDs is reserved for session temporary tablespaces. InnoDB uses session temporary tablespaces and a global temporary tablespace. Session Temporary Tablespaces Session temporary tablespaces store user-created temporary ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-transaction-scheduling.html
InnoDB uses the Contention-Aware Transaction Scheduling (CATS) algorithm to prioritize transactions that are waiting for locks. When multiple transactions are waiting for a lock on the same object, the CATS algorithm determines which transaction ...
https://dev.mysql.com/doc/refman/8.4/en/intersect.html
query_expression_body INTERSECT [ALL | DISTINCT] query_expression_body [INTERSECT [ALL | DISTINCT] query_expression_body] [...] query_expression_body: See Section 15.2.14, “Set Operations with UNION, INTERSECT, and EXCEPT” INTERSECT limits the ...
https://dev.mysql.com/doc/refman/8.4/en/invisible-columns.html
An invisible column is normally hidden to queries, but can be accessed if explicitly referenced. As an illustration of when invisible columns may be useful, suppose that an application uses SELECT * queries to access a table, and must continue to ...
https://dev.mysql.com/doc/refman/8.4/en/ipv6-server-config.html
The MySQL server listens on one or more network sockets for TCP/IP connections. Each socket is bound to one address, but it is possible for an address to map onto multiple network interfaces. Set the bind_address system variable at server startup ...