Search Results
https://dev.mysql.com/doc/refman/9.7/en/innodb-buffer-pool-in-core-file.html
The following table shows configuration and MADV_DONTDUMP support scenarios that determine whether core files are generated and whether they include buffer pool pages. The following table provides size reduction examples that you might see for a 1GB ... A core file records the status and memory image of a running ...
https://dev.mysql.com/doc/refman/9.7/en/innodb-deadlock-detection.html
InnoDB is aware of table locks if innodb_table_locks = 1 (the default) and autocommit = 0, and the MySQL layer above it knows about row-level locks. Otherwise, InnoDB cannot detect deadlocks where a table lock set by a MySQL LOCK TABLES statement or ... When deadlock detection is enabled (the default), InnoDB automatically detects transaction deadlocks and rolls back a transaction or transactions to break the ...
https://dev.mysql.com/doc/refman/9.7/en/innodb-disk-management.html
This section discusses the main considerations for I/O and disk space with the default kind of MySQL tables (also known as InnoDB tables): Controlling the amount of background I/O used to improve query performance. Organizing tables into many small ... As a DBA, you must manage disk I/O to keep the I/O subsystem from becoming saturated, and manage disk space to avoid filling up storage ...
https://dev.mysql.com/doc/refman/9.7/en/json-duality-view-metadata.html
You can obtain information about existing JSON duality views from the following Information Schema tables which have been implemented in this release: JSON_DUALITY_VIEWS: Provides per-view information about JSON duality views. JSON duality views ...
https://dev.mysql.com/doc/refman/9.7/en/keyring-key-types.html
Table 8.32, “General Keyring Key Length Limits” shows the general key-length limits. (The lower limits for keyring_aws are imposed by the AWS KMS interface, not the keyring functions.) For keyring plugins, Table 8.33, “Keyring Plugin Key Types ... MySQL Keyring supports keys of different types (encryption algorithms) and lengths: The available key types depend on which keyring plugin is ...
https://dev.mysql.com/doc/refman/9.7/en/legacy-hashing-component.html
If a generated column within any table table uses the MD5() and SHA1 functions that are removed as of MySQL 9.6.0, and MySQL server is upgraded to MySQL 9.6.0 or later, the table stops working. To resolve this, you must dispose of the generated ...
https://dev.mysql.com/doc/refman/9.7/en/locking-issues.html
MySQL manages contention for table contents using locking: Internal locking is performed within the MySQL server itself to manage contention for table contents by multiple threads. External locking occurs when the server and other programs lock ...
https://dev.mysql.com/doc/refman/9.7/en/mathematical-functions.html
One implication of this behavior is that for equal argument values, RAND(N) returns the same value each time, and thus produces a repeatable sequence of column values. It is a fast way to generate random numbers on demand that is portable between ...
https://dev.mysql.com/doc/refman/9.7/en/miscellaneous-optimization-tips.html
To fix any compression issues that occur with ARCHIVE tables, use OPTIMIZE TABLE. If possible, classify reports as “live” or as “statistical”, where data needed for statistical reports is created only from summary tables that are generated ... This section lists a number of miscellaneous tips for improving query processing speed: If your application makes several database requests to perform related updates, combining the statements into a stored routine can help ...
https://dev.mysql.com/doc/refman/9.7/en/multiple-column-indexes.html
If you specify the columns in the right order in the index definition, a single composite index can speed up several kinds of queries on the same table. If the table has a multiple-column index, any leftmost prefix of the index can be used by the ...