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https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-storage-layout.html
Once your data reaches a stable size, or a growing table has increased by tens or some hundreds of megabytes, consider using the OPTIMIZE TABLE statement to reorganize the table and compact any wasted space. OPTIMIZE TABLE copies the data part of ...The reorganized tables require less disk I/O to perform full table ...When using COMPACT row format and variable-length character sets, such as utf8mb4 or sjis, ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-transaction-management.html
InnoDB must flush the log to disk at each transaction commit if that transaction made modifications to the database. To optimize InnoDB transaction processing, find the ideal balance between the performance overhead of transactional features and ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-innodb-insertbufferactivity-category.html
Delete Merges (Delta) The total number of times the InnoDB secondary index delete buffer was merged to the InnoDB datafiles. Inserts Discarded (Delta) The total number of insert merged operations discarded Merged Recs (Delta) The total number of ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-locking.html
Transaction data for an intention lock appears similar to the following in SHOW ENGINE INNODB STATUS and InnoDB monitor output: TABLE LOCK table `test`.`t` trx id 10080 lock mode IX Record Locks A record lock is a lock on an index record. Shared and ...A shared (S) lock permits the transaction that holds the lock to read a ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-metrics-table.html
[mysqld] innodb_monitor_enable = log,metadata_table_handles_opened,metadata_table_handles_closed When enabling multiple counters or modules in a configuration file, specify the innodb_monitor_enable variable followed by counter and module names ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-buffer-pool-resize.html
Command line: $> mysqld --innodb-buffer-pool-chunk-size=134217728 Configuration file: [mysqld] innodb_buffer_pool_chunk_size=134217728 The following conditions apply when altering innodb_buffer_pool_chunk_size: If the new ... You can configure ...A ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-disk-io.html
Before writing pages to a data file, InnoDB first writes them to a storage area called the doublewrite buffer. Only after the write and the flush to the doublewrite buffer has completed does InnoDB write the pages to their proper positions in the ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-logging.html
When InnoDB has written redo log files full, it must write the modified contents of the buffer pool to disk in a checkpoint. InnoDB tries to maintain 32 redo log files of the same size, with each file equal to 1/32 * innodb_redo_log_capacity. For ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-deadlock-example.html
If client A attempts to update a row in Birds at the same time, this will lead to a deadlock: mysql> UPDATE Birds SET value=40 WHERE name='Buzzard'; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction InnoDB rolls ... The following example illustrates how an error can occur when a lock request causes a ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-standard-monitor.html
You can calculate from these numbers how many data file I/O operations your queries currently are doing. Standard Monitor output is limited to 1MB when produced using the SHOW ENGINE INNODB STATUS statement. The number of seconds is the elapsed time ... The Lock Monitor is the same as the Standard Monitor except that it includes additional lock ...SEMAPHORES This section reports threads waiting for a semaphore and ...