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https://dev.mysql.com/doc/refman/8.4/en/innodb-temporary-tablespace.html
InnoDB uses session temporary tablespaces and a global temporary tablespace. Session Temporary Tablespaces Session temporary tablespaces store user-created temporary tables and internal temporary tables created by the optimizer when InnoDB is ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-troubleshooting-datadict.html
Information about table definitions is stored in the InnoDB data dictionary. If you move data files around, dictionary data can become inconsistent. If a data dictionary corruption or consistency issue prevents you from starting InnoDB, see Section ...
https://dev.mysql.com/doc/refman/8.4/en/is-null-optimization.html
MySQL can also optimize the combination col_name = expr OR col_name IS NULL, a form that is common in resolved subqueries. MySQL can perform the same optimization on col_name IS NULL that it can use for col_name = constant_value. For example, MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/locale-support.html
The locale indicated by the lc_time_names system variable controls the language used to display day and month names and abbreviations. This variable affects the output from the DATE_FORMAT(), DAYNAME(), and MONTHNAME() functions. The lc_time_names ...
https://dev.mysql.com/doc/refman/8.4/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/8.4/en/metadata-locking.html
Metadata contention increases the more that multiple queries attempt to access the same objects. MySQL uses metadata locking to manage concurrent access to database objects and to ensure data consistency. Metadata locking applies not just to ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-api-definition.html
(NDB 8.4.0) For queries that are translated into full table scans or range scans on indexes, it is important for best performance to fetch records in properly sized batches. The speed at which queries are performed can vary by more than 40% ... The ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-data-node-memory-management.html
All memory allocation for a data node is performed when the node is started. This ensures that the data node can run in a stable manner without using swap memory, so that NDB can be used for latency-sensitive (realtime) applications. The reserved ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-disk-data-storage-requirements.html
The following items apply to Disk Data storage requirements: Variable-length columns of Disk Data tables take up a fixed amount of space. For each row, this is equal to the space required to store the largest possible value for that column. For ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-limitations-performance.html
The following performance issues are specific to or especially pronounced in NDB Cluster: Range scans. There are query performance issues due to sequential access to the NDB storage engine; it is also relatively more expensive to do many range ...