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https://dev.mysql.com/group-replication-performance-xcom-cache.html
This situation is more likely to occur if you have used the group_replication_member_expel_timeout system variable (introduced in MySQL 8.0.13) to specify an additional delay time before suspect members are expelled from a group. In this situation, ... The group communication engine for Group Replication (XCom, a Paxos variant) includes a cache for messages (and their metadata) exchanged between the group members as a part of the consensus ...
https://dev.mysql.com/group-replication-requirements.html
Transactions are executed optimistically and then, at commit time, are checked for conflicts. Bi-directional communication must be maintained at all times between all group members. Group members need to log transactions that are received from their ... Server instances that you want to use for Group Replication must satisfy the following ...
https://dev.mysql.com/group-replication-tuning-recovery.html
As state transfer from the binary log is based on classic asynchronous replication, it might take a very long time if the server joining the group does not have the group's data at all, or has data taken from a very old backup image. This minimizes ... Several aspects of Group Replication's distributed recovery process can be configured to suit your ...
https://dev.mysql.com/information-schema-optimization.html
Some INFORMATION_SCHEMA tables contain columns that provide table statistics: STATISTICS.CARDINALITY TABLES.AUTO_INCREMENT TABLES.AVG_ROW_LENGTH TABLES.CHECKSUM TABLES.CHECK_TIME TABLES.CREATE_TIME TABLES.DATA_FREE TABLES.DATA_LENGTH ...
https://dev.mysql.com/innodb-change-buffer.html
Merging cached changes at a later time, when affected pages are read into the buffer pool by other operations, avoids substantial random access I/O that would be required to read secondary index pages into the buffer pool from disk. During this ...
https://dev.mysql.com/innodb-cmp-per-index-table.html
COMPRESS_TIME The total time in seconds used for compressing data in this index. Compressed InnoDB pages are uncompressed whenever compression fails, or the first time a compressed page is accessed in the buffer pool and the uncompressed page does ... The INNODB_CMP_PER_INDEX and INNODB_CMP_PER_INDEX_RESET tables provide status information on operations related to compressed InnoDB tables and indexes, with separate statistics for each combination of database, table, and index, to help you evaluate the performance and usefulness of compression for specific ...
https://dev.mysql.com/innodb-compression-tuning-monitoring.html
To dig deeper into performance considerations for compressed tables, you can monitor compression performance at runtime using the Information Schema tables described in Example 15.1, “Using the Compression Information Schema Tables”. This ...
https://dev.mysql.com/innodb-deadlocks-handling.html
You can cope with deadlocks and reduce the likelihood of their occurrence with the following techniques: At any time, issue the SHOW ENGINE INNODB STATUS command to determine the cause of the most recent deadlock. In particular, do not leave an ...
https://dev.mysql.com/innodb-file-space.html
(These segments are different from the rollback segment, which actually contains many tablespace segments.) When a segment grows inside the tablespace, InnoDB allocates the first 32 pages to it one at a time. InnoDB can add up to 4 extents at a time ... The data files that you define in the configuration file using the innodb_data_file_path configuration option form the InnoDB system ...
https://dev.mysql.com/innodb-next-key-locking.html
The so-called phantom problem occurs within a transaction when the same query produces different sets of rows at different times. For example, if a SELECT is executed twice, but returns a row the second time that was not returned the first time, ...
Document created the 26/06/2006, last modified the 26/10/2018
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