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How to debug long-running transactions in MySQL

Among the many things that can cause a “server stall” is a long-running transaction. If a transaction remains open for a very long time without committing, and has modified data, then other transactions could block …

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Impact of the number of idle connections in MySQL

Be careful with my findings, I appear to have compile in debug mode, I am redoing the benchmarks. Updated version here. I recently had to work with many customers having large number of connections opened …

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Fighting MySQL Replication Lag

The problem of MySQL Replication unable to catch up is quite common in MySQL world and in fact I already wrote about it. There are many aspects of managing mysql replication lag such as using …

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More Gotchas with MySQL 5.0

Working on large upgrade of MySQL 4.1 running Innodb to MySQL 5.0 and doing oprofile analyzes we found very interesting issue of buf_get_latched_pages_number being responsible for most CPU usage. It did not look right. The …

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InnoDB thread concurrency

InnoDB has a mechanism to regulate count of threads working inside InnoDB. innodb_thread_concurrency is variable which set this count, and there are two friendly variables innodb_thread_sleep_delay and innodb_concurrency_tickets. I’ll try to explain how it works. …

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Measuring failover time for ScaleArc load balancer

ScaleArc hired Percona to benchmark failover times for the ScaleArc database traffic management software in different scenarios. We tested failover times for various clustered setups, where ScaleArc itself was the load balancer for the cluster. …

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How Percona tested Percona Server 5.6: A world premiere in advanced testing

8PM. One of the servers found a critical bug. Hop online and discuss, log bug. 10PM. Patch ready. 10:30PM. New build ready. 10:45PM. New RQG run initiated. This was by no means an uncommon sight …

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Measuring Max Replication Throughput on Percona XtraDB Cluster with wsrep_desync

Checking throughput with async MySQL replication Replication throughput is the measure of just how fast the slaves can apply replication (at least by my definition).  In MySQL async replication this is important to know because …

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Living with backups

Everyone does backups. Usually it’s some nightly batch job that just dumps all MySQL tables into a text file or ordinarily copies the binary files from the data directory to a safe location. Obviously both …

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The performance effects of new patches

We are going to show the effects of the new patches applied to Percona HighPerf release. As you see from the following graphs, there is significant difference to normal version when the data bigger than …

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