Query_cache and column level privileges

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 […]

More Gotchas with MySQL 5.0

Working on large upgrade of MySQL 4.1 running Innodb to MySQL 5.0 and doing oprofile analyzes we found very interesting issue of buf_get_latched_pages_number being responsible for most CPU usage. It did not look right. The close look revealed this is the function which is used to compute number of latched pages in Innodb Buffer Pool, […]

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 […]