| Bug #49360 | In some circumstances, GROUP BY WITH ROLLUP is faster then GROUP BY | ||
|---|---|---|---|
| Submitted: | 2 Dec 2009 17:53 | Modified: | 3 Apr 2011 0:21 |
| Reporter: | Rene' Cannao' | Email Updates: | |
| Status: | No Feedback | Impact on me: | |
| Category: | MySQL Server: Optimizer | Severity: | S3 (Non-critical) |
| Version: | 5.0.66 , 5.0.84 , 5.0.84 , 5.1.41, 5.1.43 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
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
[2 Dec 2009 17:57]
Rene' Cannao'
[4 Jan 2011 8:42]
Shane Bester
show profiles all output for both queries
Attachment: bug49360_5.5.9_show_profiles.txt (text/plain), 18.16 KiB.
[29 Jun 2011 16:12]
Shane Bester
the slower query spends all the time writing/updating records to disk. attached, cpu profiles.
Attachment: bug49360_5.5.13_cpu_hotspot_profile.txt (text/plain), 33.27 KiB.
[30 Oct 2011 5:59]
Shane Bester
google perf tools for group by.
Attachment: 5.5.17_group_by.pdf (application/pdf, text), 22.74 KiB.
[30 Oct 2011 5:59]
Shane Bester
google perf tools for group by with rollup.
Attachment: 5.5.17_group_by_with_rollup.pdf (application/pdf, text), 27.54 KiB.
