MySQL Bugs: #65053: Incorrect select results when using index and complicated select count(distinct(

Bug #65053	Incorrect select results when using index and complicated select count(distinct(
Submitted:	20 Apr 2012 10:52	Modified:	26 Apr 2012 8:53
Reporter:	Romans Heimanis	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	MySQL Server: DML	Severity:	S2 (Serious)
Version:	5.5.21	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	count, distinct, INDEX, SELECT

File:	Maximum allowed size is 50MB.
Description:
Privacy:

If the data you need to attach is more than 50MB, you should create a compressed archive of the data, split it to 50MB chunks, and upload each of them as a separate attachment.

To split a large file:

On *nix platforms use the split command e.g. split -b 50MB <my_large_archive> <my_split_archive_prefix>
On windows use WinZip or a similar utility to split the large file

The sql file that implement the test table and failing selects

Attachment: testcase.sql (text/x-sql), 10.44 KiB.

my.cnf config

Attachment: my.cnf (application/octet-stream, text), 2.15 KiB.

Test case (reproduced wth 5.5.17 but not 5.5.28)

Attachment: count_bug.sql (application/octet-stream, text), 1.23 KiB.