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https://dev.mysql.com/doc/refman/8.4/en/innodb-undo-logs.html
Note It is possible to encounter a concurrent transaction limit error before reaching the number of concurrent read-write transactions that InnoDB is capable of supporting. If another transaction needs to see the original data as part of a ...An ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-transaction-isolation-levels.html
If the row matches (must be updated), MySQL reads the row again and this time InnoDB either locks it or waits for a lock on it. Transaction isolation is one of the foundations of database processing. InnoDB offers all four transaction isolation ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-tablespace-autoextend-size.html
By default, when a file-per-table or general tablespace requires additional space, the tablespace is extended incrementally according to the following rules: If the tablespace is less than an extent in size, it is extended one page at a time. The ...If the tablespace is greater than 1 extent but smaller than 32 extents in size, it is extended one extent at a ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-disabling-tablespace-path-validation.html
At startup, InnoDB scans directories defined by the innodb_directories variable for tablespace files. The paths of discovered tablespace files are validated against the paths recorded in the data dictionary. If log_error_verbosity is set to 3, the ...If the paths do not match, the paths in the data dictionary are ...This ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-index-types.html
Each InnoDB table has a special index called the clustered index that stores row data. To get the best performance from queries, inserts, and other database operations, it is important to understand how InnoDB uses the clustered index to optimize ...When you define a PRIMARY KEY on a table, InnoDB uses it as the clustered ...If there is no logical unique and non-null ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-buffer-pool-stats-table.html
DATABASE_PAGES The number of pages in the InnoDB buffer pool containing data. The INNODB_BUFFER_POOL_STATS table provides much of the same buffer pool information provided in SHOW ENGINE INNODB STATUS output. Much of the same information may also ...Pages made “young” take longer to age out of the buffer pool, while pages made “not young” are moved much closer to the point of ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-troubleshooting-recovery.html
Checkpoints and advancing the checkpoint LSN are not permitted until redo log recovery is complete and data dictionary dynamic metadata (srv_dict_metadata) is transferred to data dictionary table (dict_table_t) objects. If an innodb_force_recovery ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-next-key-locking.html
If we regard a set of rows as a data item, the new phantom child would violate the isolation principle of transactions that a transaction should be able to run so that the data it has read does not change during the transaction. InnoDB performs ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-purge-configuration.html
Consequently, the InnoDB multi-version concurrency control (MVCC) system must keep a copy of the data in the undo log until all transactions that depend on that data have completed. InnoDB does not physically remove a row from the database ...A row ...This removal operation, which only occurs after the row is no longer required for multi-version concurrency control (MVCC) or rollback, is called a ...
https://dev.mysql.com/doc/refman/8.4/en/monitor-alter-table-performance-schema.html
In order of occurrence, ALTER TABLE stage events include: stage/innodb/alter table (read PK and internal sort): This stage is active when ALTER TABLE is in the reading-primary-key phase. stage/innodb/alter table (merge sort): This stage is repeated ... You can monitor ALTER TABLE progress for InnoDB tables using Performance ...For information about Performance Schema stage event instruments and ...