Emergency

Search Results for: read committed

Differences between READ-COMMITTED and REPEATABLE-READ transaction isolation levels

As an instructor with Percona I’m sometimes asked about the differences between the READ COMMITTED and REPEATABLE READ transaction isolation levels.  There are a few differences between READ-COMMITTED and REPEATABLE-READ, and they are all related …

Read More
 

Multi-threaded replication with MySQL 5.6: Use GTIDs!

MySQL 5.6 allows you to execute replicated events in parallel as long as data is split across several databases. This feature is named “Multi-Threaded Slave” (MTS) and it is easy to enable by setting slave_parallel_workers …

Read More
 

Announcing TokuDB v7.5: Read Free Replication

Today we released TokuDB® v7.5, the latest version of Tokutek’s storage engine for MySQL and MariaDB. I’ll be publishing two blogs next week to go into more details about our new “Read Free Replication”, but …

Read More
 

READ-COMMITED vs REPETABLE-READ in tpcc-like load

Question what is better isolation level is poping up again and again. Recently it was discussed in InnoDB : Any real performance improvement when using READ COMMITED isolation level ? and in Repeatable read versus …

Read More
 

Percona Server 5.6.25-73.0 is now available

Percona is glad to announce the release of Percona Server 5.6.25-73.0 on July 1, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories. Based on MySQL 5.6.25, including all the bug …

Read More
 

Percona XtraDB Cluster 5.6.24-25.11 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on June 3rd 2015. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.6.24-72.2 including all …

Read More
 

MySQL performance implications of InnoDB isolation modes

Over the past few months I’ve written a couple of posts about dangerous debt of InnoDB Transactional History and about the fact MVCC can be the cause of severe MySQL performance issues. In this post …

Read More
 

How to deal with MySQL deadlocks

A deadlock in MySQL happens when two or more transactions mutually hold and request for locks, creating a cycle of dependencies. In a transaction system, deadlocks are a fact of life and not completely avoidable. …

Read More
 

InnoDB’s gap locks

One of the most important features of InnoDB is the row level locking. This feature provides better concurrency under heavy write load but needs additional precautions to avoid phantom reads and to get a consistent …

Read More