October 22, 2014

Recover BLOB fields

For a long time long types like BLOB, TEXT were not supported by Percona InnoDB Recovery Tool. The reason consists in a special way InnoDB stores BLOBs. An InnoDB table is stored in a clustered index called PRIMARY. It must exist even if a user hasn’t defined the primary index. The PRIMARY index pages are […]

SystemTap – DTrace for Linux ?

Since DTrace was released for Solaris I am missing it on Linux systems… It can’t be included in Linux by the same reason why ZFS can’t be – it’s licensing issue. Both ZFS and DTrace are under CDDL, which is incompatible with GPL. So you can see DTrace and ZFS on Solaris, FreeBSD, MacOS, but […]

How to pretty-print my.cnf with a one-liner

When I’m looking at a server, I often want to see the /etc/my.cnf file nicely formatted, and with comments stripped. This Perl one-liner will pretty-print the file:

Handling big result sets

Sometime it is needed to handle a lot of rows on client side. Usual way is send query via mysql_query and than handle the result in loop mysql_fetch_array (here I use PHP functions but they are common or similar for all APIs, including C). Consider table: