Vadim asked me yesterday to update Microslow patch for 5.1.21, because the previous one I wrote for 5.1.20 failed to apply correctly on the new MySQL release. Imagine the expression on my face after I unpacked the sources and found out that MySQL incorporated the patch to their release. So it’s a built-in feature […]Read more
Microslow patch has been there for some time, but only for earlier MySQL editions such as 4.1 and 5.0. Now it’s also available for the latest 5.1.
Because MySQL went through a lot of internal changes, the patch had to be written from scratch. It introduces some minor change in existing functionality and also […]
Just short message that patch enables microsecond resolution in slow-log (see more https://www.percona.com/blog/2006/09/06/slow-query-log-analyzes-tools/) for 5.0.37 is available here:
The patch for 5.0.41 :
Update 3 June 2008: We have removed the builds below, since they are quite obsolete and no one has posted comments about them since more than a year ago.
Great news are MySQL finally released new Community release – MySQL 5.0.33, which however as promised comes without Binaries.
This version also does not have any community […]
Taking into account 4.1 tree is still popular and is used on many production servers we
decided to make backport of patch to slow-log queries. The patch allows to specify time of slow queries in microseconds and is very helpful in a fight with problematic queries. 4.1 Patch is available here (The original patch was […]
InnoDB uses its own mutexes and read-write locks instead of POSIX-mutexes pthread_mutex*, the main reason for that is performance, but InnoDB’s implementation isn’t ideal and on modern SMP boxes can cause serious performance problems.
Let’s look on InnoDB mutex (schematic for simplification):
(There is an updated version of this post here). MySQL has simple but quite handy feature – slow query log, which allows you to log all queries which took over define number of seconds to execute. There is also an option to enable logging queries which do not use indexes even if they take […]Read more
I’m again returning to InnoDB scalability and related bug #15815 as it hurts many users and customers using multi-cpu servers.
Short intro into problem:
On 4-CPU box 1 thread executes full-table scan select query for 8 sec,
but with 4 threads – each thread executes query for 240 sec.
It is very strange as threads use only SELECT […]
We are going to release several patches which are not included in official MySQL releases.
First one is automatically stack trace for x86_64 systems. Currently MySQL resolves stack in crash only for x86 boxes.
You can download patch for 5.0.22 source tree here.
How to use: place stack64.diff into main source dir; execute patch -p1 < stack64.diff. One [...]