Contents
What is MySQL replication lag?
MySQL Curriculum Developer. Replication lag occurs when the slaves (or secondaries) cannot keep up with the updates occuring on the master (or primary). Unapplied changes accumulate in the slaves’ relay logs and the version of the database on the slaves becomes increasingly different from that of the master.
What is MySQL Gtid?
A global transaction identifier (GTID) is a unique identifier created and associated with each transaction committed on the server of origin (source). The example just shown represents the first through fifth transactions originating on the MySQL Server whose server_uuid is 3E11FA47-71CA-11E1-9E33-C80AA9429562 .
What type of replication does MySQL support?
asynchronous replication
Replication in MySQL features support for one-way, asynchronous replication, in which one server acts as the source, while one or more other servers act as replicas. This is in contrast to the synchronous replication which is a characteristic of NDB Cluster (see Chapter 18, MySQL NDB Cluster 7.3 and NDB Cluster 7.4).
When to use delayed replication in MySQL 5.7?
MySQL 5.7 also supports delayed replication such that a replica deliberately lags behind the source by at least a specified amount of time; see Section 16.3.10, “Delayed Replication”. For scenarios where synchronous replication is required, use NDB Cluster (see Chapter 21, MySQL NDB Cluster 7.5 and NDB Cluster 7.6 ).
Why is mysql query so slow in 5.7?
In MySQL 5.7 it is taking over 11.5 seconds at first and 1.4 seconds every recurring execution without restarting MySQL. And the more LEFT JOINs I add to the query, the slower the query becomes in MySQL 5.7. Both instances now run on the same machine, on the same hard drive and with the same my.ini settings. So it isn’t hardware.
Which is faster MySQL 5.5 or 5.7?
My problem is that this query is performing fast in MySQL 5.5 but extremely slow in MySQL 5.7. In MySQL 5.5 it is taking over 1 second at first and < 0.001 seconds every recurring execution without restarting MySQL. In MySQL 5.7 it is taking over 11.5 seconds at first and 1.4 seconds every recurring execution without restarting MySQL.
How long does MySQL 5.7 database query take?
In MySQL 5.5 it is taking over 1 second at first and < 0.001 seconds every recurring execution without restarting MySQL. In MySQL 5.7 it is taking over 11.5 seconds at first and 1.4 seconds every recurring execution without restarting MySQL.