Search Results
https://dev.mysql.com/doc/refman/8.4/en/information-schema-partitions-table.html
The indexing can change as partitions are added, dropped, and reorganized; the number shown is this column reflects the current order, taking into account any indexing changes. Each row in this table corresponds to an individual partition or ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-statistics-table.html
Take this into account when specifying a prefix length for a nonbinary string column that uses a multibyte character set. The information_schema_stats_expiry system variable defines the period of time before cached table statistics expire. If there ...
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. The adaptive hash index enables InnoDB to perform more like an in-memory ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-compression-usage.html
The actual compression algorithm is not affected by the KEY_BLOCK_SIZE value; the value determines how large each compressed chunk is, which in turn affects how many rows can be packed into each compressed page. Compressed tables can be created in ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-disk-management.html
Organizing tables into many small files, a few larger files, or a combination of both. 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 devices. The ACID design ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-compression-tables.html
There are two pairs of InnoDB INFORMATION_SCHEMA tables about compression that can provide insight into how well compression is working overall: INNODB_CMP and INNODB_CMP_RESET provide information about the number of compression operations and the ...INNODB_CMPMEM and INNODB_CMPMEM_RESET provide information about the way memory is allocated for ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-internal-data.html
The data exposed by the transaction and locking tables (INFORMATION_SCHEMA INNODB_TRX table, Performance Schema data_locks and data_lock_waits tables) represents a glimpse into fast-changing data. This is not like user tables, where the data ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-tables.html
INFORMATION_SCHEMA InnoDB tables can be used to monitor ongoing InnoDB activity, to detect inefficiencies before they turn into issues, or to troubleshoot performance and capacity issues. For related information and examples, see Section 17.15, ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-understanding-innodb-locking.html
For a lock to be acquired by a transaction, all incompatible lock requests previously entered into the lock queue for that row or table must be removed (which occurs when the transactions holding or requesting those locks either commit or roll back). When a transaction updates a row in a table, or locks it with SELECT FOR UPDATE, InnoDB establishes a list or queue of locks on that ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-multiple-buffer-pools.html
For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency, by reducing contention as different threads read and write to cached pages. This feature is typically intended for ...