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Query_cache and column level privileges

 | August 6, 2007 |  Posted In: Insight for Developers

Recently we were puzzled by question how query_cache works with column level privileges. The question was appeared as we discovered function query_cache_send_result_to_client is called before real parsing of query, so at the moment of execution the query_cache is not able to know which columns are accessed. Looking into source code I found out that in […]

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Beware large Query_Cache sizes

 | March 23, 2007 |  Posted In: Insight for DBAs

During last couple of months I had number of consulting projects with MySQL Query Cache being source of serious problems. One would see queries both for MyISAM and Innodb tables mysteriously stalling for few seconds with “NULL” in State column. These could be troubleshooted to waiting on Query Cache which at the same time had […]

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Percona Monitoring and Management 1.1.2 is Now Available

 | April 3, 2017 |  Posted In: Database Monitoring, Events and Announcements, MariaDB, MongoDB, MySQL, Orchestrator, Percona Monitoring and Management, Percona Software, PMM, ProxySQL, ProxySQL

Percona Monitoring and Management

Percona announces the release of Percona Monitoring and Management 1.1.2 on April 3, 2017. For installation instructions, see the Deployment Guide. This release includes several new dashboards in Metrics Monitor, updated versions of software components used in PMM Server, and a number of small bug fixes.

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A Look at MariaDB Subquery Cache

 | March 2, 2017 |  Posted In: MariaDB, MySQL

MariaDB Subquery Cache

The MariaDB subquery cache feature added in MariaDB 5.3 is not widely known. Let’s see what it is and how it works. What is a subquery cache? The MariaDB subquery cache optimizes the execution of correlated subqueries. Correlated subqueries refer to a value from the parent query. For example:

MariaDB only uses this optimization if […]

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Millions of Queries per Second: PostgreSQL and MySQL’s Peaceful Battle at Today’s Demanding Workloads

and  | January 6, 2017 |  Posted In: Benchmarks, InnoDB, MySQL, open source databases, OpenSource Databases on big machines, Percona Live

PostgreSQL and MySQL

This blog compares how PostgreSQL and MySQL handle millions of queries per second. Anastasia: Can open source databases cope with millions of queries per second? Many open source advocates would answer “yes.” However, assertions aren’t enough for well-grounded proof. That’s why in this blog post, we share the benchmark testing results from Alexander Korotkov (CEO of […]

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Is Your Query Cache Really Disabled?

and  | November 11, 2016 |  Posted In: MySQL

Query Cache

This blog post was motivated by an internal discussion about how to fully disable query cache in MySQL. According to the manual, we should be able to disable “Query Cache” on the fly by changing query_cache_type to 0, but as we will show this is not fully true. This blog will show you how to properly disable “query […]

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Percona Server 5.6.33-79.0 is now available

 | October 18, 2016 |  Posted In: Events and Announcements, MySQL, Percona Server, Percona Software, TokuDB

Percona Server for MySQL 5.7.18-15

Percona announces the release of Percona Server 5.6.33-79.0 on October 18th, 2016. Download the latest version from the Percona web site or the Percona Software Repositories. Based on MySQL 5.6.33, including all the bug fixes in it, Percona Server 5.6.33-79.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source and free – this […]

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MySQL 5.7 Performance Tuning Immediately After Installation

 | October 12, 2016 |  Posted In: InnoDB, MySQL

MySQL 5.7 Performance Tuning

This blog updates Stephane Combaudon’s blog on MySQL performance tuning, and covers MySQL 5.7 performance tuning immediately after installation. A few years ago, Stephane Combaudon wrote a blog post on Ten MySQL performance tuning settings after installation that covers the (now) older versions of MySQL: 5.1, 5.5 and 5.6. In this post, I will look […]

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Testing Samsung storage in tpcc-mysql benchmark of Percona Server

 | July 26, 2016 |  Posted In: Benchmarks, MySQL

tpcc-mysql benchmark

This blog post will detail the results of Samsung storage in tpcc-mysql benchmark using Percona Server. I had an opportunity to test different Samsung storage devices under tpcc-mysql benchmark powered by Percona Server 5.7. You can find a summary with details here https://github.com/Percona-Lab-results/201607-tpcc-samsung-storage/blob/master/summary-tpcc-samsung.md I have in my possession: Samsung 850 Pro, 2TB: This is a SATA device and […]

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