Search Results for: php session

Read/Write Splitting with PHP Webinar Questions Followup

Today I gave a presentation on “Read/Write Splitting with PHP” for Percona 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 I could during the session, but here are […]

Percona sessions at the MySQL conference

Many Percona employees will be at the 2010 MySQL conference. We’ll be giving a lot of informative technical talks on various topics. Here’s a list: Morgan Tocker, Baron Schwartz: Diagnosing and Fixing MySQL Performance Problems Peter Zaitsev: Scaling Applications with Caching, Sharding and Replication Baron Schwartz: EXPLAIN Demystified Vadim Tkachenko: An Overview of Flash Storage […]

Are PHP persistent connections evil ?

As you probably know PHP “mysql” extension supported persistent connections but they were disabled in new “mysqli” extension, which is probably one of the reasons some people delay migration to this extension. The reason behind using persistent connections is of course reducing number of connects which are rather expensive, even though they are much faster […]

mk-query-digest, query comments and the query cache

I very much like the fact that MySQL allows you to embed comments into SQL statements. These comments are extremely convenient, because they are written into MySQL log files as part of the query. This includes the general log, the binary log and the slow query log. Maatkit includes tools which interact with these logs, […]

Worse than DDOS

Today I worked on rather interesting customer problem. Site was subject what was considered DDOS and solution was implemented to protect from it. However in addition to banning the intruders IPs it banned IPs of web services which were very actively used by the application which caused even worse problems by consuming all apache slots […]

Commodity Hardware, Commodity Software and Commodity People

In the previous post I mentioned not all architectures and solutions work for Commodity People, and people seems to agree with me. Number of vendors would claim they are in Commodity Software or Hardware business but few would probably mention they are doing it for Commodity People, because few people would like to be called […]

Optimizer hints in MySQL 5.7.7 – The missed manual

In version MySQL 5.7.7 Oracle presented a new promising feature: optimizer hints. However it did not publish any documentation about the hints. The only note which I found in the user manual about the hints is: It is now possible to provide hints to the optimizer by including /*+ … */ comments following the SELECT, […]

Profiling MySQL queries from Performance Schema

When optimizing queries and investigating performance issues, MySQL comes with built in support for profiling queries aka SET profiling = 1; . This is already awesome and simple to use, but why the PERFORMANCE_SCHEMA alternative? Because profiling will be removed soon (already deprecated on MySQL 5.6 ad 5.7); the built-in profiling capability can only be enabled per session. This […]

InnoDB locks and deadlocks with or without index for different isolation level

Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels. Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave […]