MySQL Bugs: #78993: Optimizer use index scan instead of range scan by mistake

Bug #78993	Optimizer use index scan instead of range scan by mistake
Submitted:	28 Oct 2015 3:15	Modified:	1 Feb 2016 15:54
Reporter:	zhang yingqiang (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:	5.6.16 5.6.26, 5.6.27	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	Optimizer, regression

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

fix for order by limt cause

Attachment: a.diff (application/octet-stream, text), 1.20 KiB.

just part of code, which we may calculate the cost by considering read plan before.

Attachment: a.diff (application/octet-stream, text), 1.25 KiB.