Bug #32041 tiny memory leak if example udf is loaded and unloaded

• Submitted: 2 Nov 2007 2:31
• Modified: 23 Mar 2009 18:43
• Reporter: Shane Bester (Platinum Quality Contributor)
• Status: Verified
• Category: MySQL Server: User-defined functions ( UDF )
• Severity: S3 (Non-critical)
• Version: 5.1.23-debug, 5.1, 6.0 bzr
• OS: Any (MS Windows, Linux)
• CPU Architecture: Any
• Tags: memory leak

[2 Nov 2007 2:31] Shane Bester

Description:
When loading and unloading the example udf in a loop, the server's memory usage continues to rise.

In my test so far, 9.7 million loops consumed roughly ~400MB of memory in the server process.

How to repeat:
#do this a few million times in a loop.  leave it for some hours:

drop function metaphon;
create metaphon returns string soname 'udf_example.dll';

Suggested fix:
Run under valgrind and find the leak if it exists.

[2 Nov 2007 10:02] MySQL Verification Team

typo. meant this:

drop function metaphon;
create function metaphon returns string soname 'udf_example.dll';

[23 Mar 2009 18:43] Sveta Smirnova

Thank you for the report.

Verified as described.

Test case:

--source include/have_udf.inc

--eval create function metaphon returns string soname "$UDF_EXAMPLE_LIB"

--disable_query_log
let $i=1000000;
while ($i)
{
drop function metaphon;
--eval create function metaphon returns string soname "$UDF_EXAMPLE_LIB"
dec $i;
}
--enable_query_log

select 1;

Options:

$UDF_EXAMPLE_LIB_OPT

Then examine memory usage while test is running.

[31 Jan 2013 10:06] MySQL Verification Team

still leaks memory on mysql-trunk !

[28 Apr 2016 8:51] MySQL Verification Team

still affects current 5.8.0-dmr