Tag - contention

PostgreSQL locking, part 2: heavyweight locks

Locking in PostgreSQL

PostgreSQL locking visibility for application developers and DBAs is in most cases related to heavyweight locks. Complex database locking operations require full instrumentation using views from the system catalog. It should be clear which object is locked by a specific database “backend” process. An alternative name for any lock is “bottleneck”. In order to […]

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MySQL and Linux Context Switches

Context Switches

In this blog post, I’ll look at MySQL and Linux context switches and what is the normal number per second for a database environment.
You might have heard many times about the importance of looking at the number of context switches to indicate if MySQL is suffering from the internal contention issues. I often […]

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How We Made Percona XtraDB Cluster Scale

wsrep-stages

In this blog post, we’ll look at the actions and efforts Percona experts took to scale Percona XtraDB Cluster.
Introduction
When we first started analyzing Percona XtraDB Cluster performance, it was pretty bad. We would see contention even with 16 threads. Performance was even worse with sync binlog=1, although the same pattern was observed even with the […]

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InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight:
Scalability issues due to tables without primary keys
This scalability issue is caused by the usage of tables without primary keys. This issue typically shows itself […]

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