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 developed by Georg Richter georg at php net)

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Ruslan Zakirov

Thanks. I’m going to use it once I had time.

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Michael Monashev

Thanks.
Very usfull patch for query profiling.

Большое спасибо.

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Michael Monashev

I patch mysql source, but it doesn’t work.

I can not set long_query_time=0 . The least value of long_query_time – 1. If I set long_query_time=0, “SHOW VARIABLES;” show me long_query_time=1.

And I see always seconds in slow log: Query_time: 2 Lock_time: 0 .

How to turn on the patch?

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Vadim Tkachenko

Michael,

It looks like you are still using unpatched mysqld.

The procedure is:
get sources
patch with: patch -p1 < patch.slow-micro.4.1.21.diff ./configure --prefix=/usr/local/mysql-micro ...other-options.. make make install In /usr/local/mysql-micro you should get binary

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Michael Monashev

I do it again, how you write.
After I run slow query and get this:

# Time: 061010 0:58:54
# User@Host: root[root] @ localhost []
# Query_time: 7 Lock_time: 0 Rows_sent: 1 Rows_examined: 227073
use mindmix;
SELECT SQL_CALC_FOUND_ROWS * FROM topics WHERE forum_id !=1 LIMIT 1;

Do you have another ideas?

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Michael Monashev

I use MyISAM tables…

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Michael Monashev

Sorry, I find problem.
I used old mysqld.

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Peter Zaitsev

Michael,

Good you’ve found the problem. Regarding query you have in your example it is slow because of SQL_CALC_FOUND_ROWS – it effectively negates the limit.

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