Search Results for: wrong index

Q&A: Common (but deadly) MySQL Development Mistakes

On Wednesday I gave a presentation on “How to Avoid Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as we had time […]

How rows_sent can be more than rows_examined?

When looking at queries that are candidates for optimization I often recommend that people look at rows_sent and rows_examined values as available in the slow query log (as well as some other places). If rows_examined is by far larger than rows_sent, say 100 larger, then the query is a great candidate for optimization. Optimization could […]

Percona XtraDB Cluster 5.6.15-25.4 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on February 20th 2014. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.6.15-63.0 including all the bug fixes in it, Galera Replicator 3.3 and on Codership wsrep API 5.6.15-25.2 is now the current General Availability […]

Percona XtraDB Cluster 5.6 GA release now available

Percona is pleased to announce the first General Availability release of the leading open source High Availability solution for MySQL, Percona XtraDB Cluster 5.6 on January 30, 2014. Binaries are available from downloads area or from our software repositories. Percona XtraDB Cluster 5.6 Percona XtraDB Cluster 5.6 is an active/active cluster solution for High Availability (HA) MySQL […]

2 cases for MySQL server overload

Your MySQL server is overloaded. You see hundreds of running queries in the SHOW PROCESSLIST taking many seconds to run, or can’t connect at all because all connections slots are busy. If you have worked with MySQL long enough you surely have seen it, probably more than once. This is what I would call “MySQL […]

Schema Design in MongoDB vs Schema Design in MySQL

For people used to relational databases and doing MySQL database design, using NoSQL solutions such as MongoDB brings interesting challenges. One of them is schema design: while in the relational world, normalization is a good way to start, how should we design our collections when creating a new MongoDB application? Let’s see with a simple […]

Recovering temporal types in MySQL 5.6: TIME, TIMESTAMP and DATETIME

MySQL 5.6 introduces a new feature – microseconds resolution in some temporal types. As of 5.6.4 TIME, TIMESTAMP and DATETIME can have a fractional part. To create a field with subseconds you can specify precision in brackets: TIME(3), DATETIME(6) etc. Obviously, the new feature requires the format change. All three types may now have a […]

Schema changes – what’s new in MySQL 5.6?

Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes. While it is usually not a problem for small tables or those in early stages of product life cycle, schema changes become a […]