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https://dev.mysql.com/doc/refman/8.0/en/innodb-compression-tuning-monitoring.html
This information is more targeted and more useful for evaluating compression efficiency and diagnosing performance issues one table or index at a time. The key statistics to consider are the number of, and amount of time spent performing, ...The ...
https://dev.mysql.com/doc/refman/8.0/en/entering-queries.html
Here is a simple query that asks the server to tell you its version number and the current date. These values are imprecise because they represent wall clock time (not CPU or machine time), and because they are affected by factors such as server ...
https://dev.mysql.com/doc/refman/8.0/en/timestamp-lookups.html
Temporal values are stored in TIMESTAMP columns as UTC values, and values inserted into and retrieved from TIMESTAMP columns are converted between the session time zone and UTC. If the session time zone is UTC, there is effectively no time zone ...
https://dev.mysql.com/doc/refman/8.0/en/ibd2sdi.html
During DDL operations, ROLLBACK operations, and undo log purge operations related to SDI, there may be a short interval of time when ibd2sdi fails to read SDI data stored in the tablespace. ibd2sdi can be run on file-per-table tablespace files ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-benefits.html
InnoDB crash recovery automatically finalizes changes that were committed before the time of the crash, and undoes changes that were in process but not committed, permitting you to restart and continue from where you left off. Inserts, updates, and ... InnoDB tables have the following benefits: If the server unexpectedly exits because of a hardware or software issue, regardless of what was happening in the database at the time, you don't need to do anything special after restarting the ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-information-schema-metrics-table.html
The TIME_ENABLED and TIME_ELAPSED values indicate when the counter was last enabled and how many seconds have elapsed since that time. Values such as COUNT, MAX_COUNT, and AVG_COUNT, which cumulatively collect data from the time the counter is ...
https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html
If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row occurs. With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row ...If column b is also unique, the INSERT is equivalent to this UPDATE statement instead: UPDATE t1 SET c=c+1 WHERE a=1 OR b=2 LIMIT 1; If a=1 OR b=2 matches several rows, only one row is ...If ...
https://dev.mysql.com/doc/refman/8.0/en/replication-gtids-howto.html
This is a “cold start” procedure that assumes either that you are starting the source server for the first time, or that it is possible to stop it; for information about provisioning replicas using GTIDs from a running source server, see Section ... This section describes a process for configuring and starting GTID-based replication in MySQL ...For information about ...
https://dev.mysql.com/doc/refman/8.0/en/group-replication-understanding-consistency-guarantees.html
With the first approach, the group takes the minimum time possible to secure a stable group membership after a primary failure by electing a new primary and then allowing data access immediately while it is still applying any possible backlog from ...The events that relate to the consistency of a system can be split into control operations, either manual or automatically triggered by failures; and data flow ...
https://dev.mysql.com/doc/refman/8.0/en/replication-rules-channel-based-filters.html
Channel specific replication filters are particularly useful in a multi-source replication topology when the same database or table is present on multiple sources, and the replica is only required to replicate it from one source. For instructions to ... This section explains how to work with replication filters when multiple replication channels exist, for example in a multi-source replication ...