Bug #46648 SQL_CALC_FOUND_ROWS kills performance with ORDER BY and LIMIT
Submitted: 11 Aug 2009 11:41 Modified: 17 Aug 2009 13:36
Reporter: Jille Timmermans Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Optimizer Severity:S3 (Non-critical)
Version:5.1.32, 4.1, 5.0, 5.1, azalea bzr OS:Linux (2.6.28.7)
Assigned to: CPU Architecture:Any
Tags: limit, order by, performance, sql_calc_found_rows

File: Maximum allowed size is 3MB.
Description:
Privacy:

If the data you need to attach is more than 3MB, you should create a compressed archive of the data and a README file that describes the data with a filename that includes the bug number (recommended filename: mysql-bug-data-46648.zip) and upload one to sftp.oracle.com. A free Oracle Web (SSO) account (the one you use to login bugs.mysql.com) and a client that supports SFTP are required in order to access the SFTP server.

To upload the file to sftp.oracle.com:

  1. Open an SFTP client and connect to sftp.oracle.com. Specify port 2021 and remote directory /support/incoming/.
  2. Log in with your newly created Oracle Web account (email address) and password.
  3. Upload the archive to /support/incoming.
  4. Once you have uploaded the file, add a comment to this bug to notify us about it.
Example: sftp -oPort=2021 -oUser=email sftp.oracle.com:/support/incoming

Usage Notes: This directory is unlistable, which means that once you have uploaded your file, you will not be able to see it. A file cannot be uploaded more than once with the same filename. The filename must be changed before attempting to upload the file again. The filename should always start with mysql-bug- prefix. Files are retained on the SFTP server for 7 days and then permanently removed.

[12 Aug 2009 6:20] Sveta Smirnova
test case for the testsuite

Attachment: bug46648.test (application/octet-stream, text), 1.11 KiB.