Search Results for: update statistic

When Does InnoDB Update Table Statistics? (And When It Can Bite)

An InnoDB table statistics is used for JOIN optimizations and helping the MySQL optimizer choose the appropriate index for a query. If a table’s statistics or index cardinality becomes outdated, you might see queries which previously performed well suddenly show up on slow query log until InnoDB again updates the statistics. But when does InnoDB […]

Google’s user_statistics V2 port and changes

Recently Google published V2 release of patches, one of them user_statistics we use in our releases. New features are quite interesting so we decided to port it to fresh releases of MySQL. Features includes: New statistics per user (Cpu_time, Bytes_received, Bytes_sent, etc) New command SHOW CLIENT_STATISTICS, which shows statistics per client’s hostname, not per user […]

InnoDB’s multi-versioning handling can be Achilles’ heel

I believe InnoDB storage engine architecture is great for a lot of online workloads, however, there are no silver bullets in technology and all design choices have their trade offs. In this blog post I’m going to talk about one important InnoDB limitation that you should consider. InnoDB is a multiversion concurrency control (MVCC) storage […]

Google Compute Engine adds Percona XtraDB Cluster to click-to-deploy process

I’m happy to announce that Google has added Click-to-deploy functionality for Percona XtraDB Cluster (PXC) on Google Cloud Compute nodes. This gives you the ability to rapidly spin up a cluster for experimentation, performance testing, or even production use on Google Compute Engine virtual machines. What is Percona XtraDB Cluster? Percona XtraDB Cluster is a […]

MySQL upgrade best practices

MySQL upgrades are necessary tasks and we field a variety of questions here at Percona Support regarding MySQL upgrade best practices. This post highlights recommended ways to upgrade MySQL in different scenarios. Why are MySQL upgrades needed? The reasons are many and include: Access to new features, performance benefits, bug fixes…. However, MySQL upgrades can […]

Using MySQL 5.6 Performance Schema in multi-tenant environments

Hosting a shared MySQL instance for your internal or external clients (“multi-tenant”) was always a challenge. Multi-tenants approach or a “schema-per-customer” approach is pretty common nowadays to host multiple clients on the same MySQL sever. One of issues of this approach, however, is the lack of visibility: it is hard to tell how many resources (queries, disk, […]

Tools and tips for analysis of MySQL’s Slow Query Log

MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check this and this, too) but […]

Automatic replication relaying in Galera 3.x (available with PXC 5.6)

A decade ago MySQL folks were in love with the concept of a relay slave for MySQL high availability across data centers.  A relay is a single slave in a remote data center that receives replication from the global master and, in turn, replicates to all the other local slaves in that data center.  This saved […]