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https://dev.mysql.com/doc/refman/8.4/en/innodb-adaptive-hash.html
If a table fits almost entirely in main memory, a hash index speeds up queries by enabling direct lookup of any element, turning the index value into a sort of pointer. If InnoDB notices that queries could benefit from building a hash index, it does ... The adaptive hash index enables InnoDB to perform more like an in-memory database on systems with appropriate combinations of workload and sufficient memory for the buffer pool without sacrificing transactional features or ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-and-mysql-replication.html
It is possible to use replication in a way where the storage engine on the replica is not the same as the storage engine on the source. For example, you can replicate modifications to an InnoDB table on the source to a MyISAM table on the replica.
https://dev.mysql.com/doc/refman/8.4/en/innodb-buffer-pool.html
By default, pages read by queries are immediately moved into the new sublist, meaning they stay in the buffer pool longer. The buffer pool is an area in main memory where InnoDB caches table and index data as it is accessed. The buffer pool permits ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-temp-table-info.html
INNODB_TEMP_TABLE_INFO provides information about user-created InnoDB temporary tables that are active in the InnoDB instance. It does not provide information about internal InnoDB temporary tables used by the optimizer. mysql> SHOW TABLES FROM ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-locks-set.html
It is important to create good indexes so that your queries do not scan more rows than necessary. A locking read, an UPDATE, or a DELETE generally set record locks on every index record that is scanned in the processing of an SQL statement. It does ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-next-key-locking.html
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, ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-row-format.html
The row format of a table determines how its rows are physically stored, which in turn can affect the performance of queries and DML operations. As more rows fit into a single disk page, queries and index lookups can work faster, less cache memory ...The pages that make up each table are arranged in a tree data structure called a B-tree ...
https://dev.mysql.com/doc/refman/8.4/en/join.html
Such subqueries must include an alias to give the subquery result a table name, and may optionally include a list of table column names in parentheses. mysql> SELECT * FROM t1 NATURAL RIGHT JOIN t2; +------+------+------+ | a | c | b | ... MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/json-table-functions.html
This section contains information about JSON functions that convert JSON data to tabular data. JSON_TABLE(expr, path COLUMNS (column_list) [AS] alias) Extracts data from a JSON document and returns it as a relational table having the specified ...
https://dev.mysql.com/doc/refman/8.4/en/kill.html
KILL [CONNECTION | QUERY] processlist_id Each connection to mysqld runs in a separate thread. Thread processlist identifiers can be determined from the ID column of the INFORMATION_SCHEMA PROCESSLIST table, the Id column of SHOW PROCESSLIST output, ...