April 18, 2014

Apache PHP MySQL and Runaway Scripts

Sometimes due to programming error or due to very complex query you can get your PHP script running too long, well after user stopped waiting for the page to render and went browsing other sites. Looking at Server-Status I’ve seen scripts executing for hours sometimes which is obviously the problem – they take Apache Slot, […]

trx descriptors: MySQL performance improvements in Percona Server 5.5.30-30.2

One major problem in terms of MySQL performance that still stands in the way of InnoDB scalability is the trx_list scan on consistent read view creation. It was originally reported as a part of MySQL bug #49169 and can be described as follows. Whenever a connection wants to create a consistent read, it has to […]

PHP vs. BIGINT vs. float conversion caveat

Sometimes you need to work with big numbers in PHP (gulp). For example, sometimes 32-bit identifiers are not enough and you have to use BIGINT 64-bit ids; e.g. if you are encoding additional information like the server ID into high bits of the ID. I had already written about the mess that 64-bit integers are […]

PHP Large result sets and summary tables.

We’re working with web site preparing for massive growth. To make sure it handles large data sets as part of the process we work on generation test database of significant size as testing your application on table with 1000 rows may well give you very dangerous false sense of security. One of the process web […]

MySQL Installation and upgrade scripts.

I generally find MySQL Sever sufficiently tested, meaning at least minor version upgrades rarely cause the problems. Of course it is not perfect and I remember number of big issues when some releases could not be used due to behavior changes in them and when something had to be rolled back in the next release. […]

Integers in PHP, running with scissors, and portability

Until recently I thought that currently popular scripting languages, which mostly evolved over last 10 years or something, must allow for easier portability across different platforms compared to ye good olde C/C++. After all, their development started a few decades after C, so its notorious caveats are all well-known and should be easy to avoid […]

PHP Sessions – Files vs Database Based

One may think changing PHP session handler from file based to database driven is fully transparent. In many cases it is, sometimes however it may cause some unexpected problems as happened to one of our customers. If you use file based sessions PHP will lock session file for whole script execution duration, which means all […]

Alternatives of PHP ?

When I loaded GigaBytes of XMLs into mysql database with PHP script, I was thinking about PHP alternatives. Why do I need that ? 1. PHP is slow – I’m speaking about area of data processing and implementation of algorithms 2. No good cli debugger – I’m just tired of debugging with ‘echo’ and ‘var_dump’ […]

Percona Monitoring Plugins 1.1.3. Addressed CVE-2014-2569.

Percona is glad to announce the release of Percona Monitoring Plugins 1.1.3. Changelog: * Introduced more secure location of PHP script configs to harden a Cacti setup * Addressed CVE-2014-2569 We have introduced a more secure location /etc/cacti/ for PHP script configs. Earlier, the only way was to keep .php.cnf configs inside of scripts/ folder […]

Percona Monitoring Plugins 1.1, now with Zabbix support

Percona is glad to announce the release of Percona Monitoring Plugins 1.1. The components are designed to integrate seamlessly with widely deployed solutions such as Nagios, Cacti and Zabbix, and are delivered in the form of templates, plugins, and scripts. In this release we have added MySQL template for Zabbix 2.0.x adopted from the existing […]