Bug #97001 Dangerous optimization reconsidering_access_paths_for_index_ordering
Submitted: 25 Sep 2019 0:35 Modified: 3 Apr 2020 22:41
Reporter: Jeremy Cole (Basic Quality Contributor) (OCA) Email Updates:
Status: Closed Impact on me:
Category:MySQL Server: Optimizer Severity:S2 (Serious)
Version:5.7, 5.7.27 OS:Any
Assigned to: CPU Architecture:Any
Tags: Contribution, limit, Optimizer, primary key, reconsidering_access_paths_for_index_ordering

File: Maximum allowed size is 50MB.

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:

[25 Sep 2019 0:39] Jeremy Cole
Patch to implement reconsider_index_for_order optimizer_switch

Attachment: reconsider_index_for_order_20190924.patch.txt (text/plain), 8.20 KiB.

[25 Sep 2019 0:39] Jeremy Cole
Test case demonstrating slow query resulting from bad optimization

Attachment: reconsider_index_for_order_bad_optimization.test (application/octet-stream, text), 2.94 KiB.

[25 Sep 2019 7:10] Umesh Shastry
mtr test results -  5.7.27, 5.6.45 and 8.0.17

Attachment: 97001.results (application/octet-stream, text), 12.66 KiB.