MySQL Bugs: #81022: P_S.*.DIGEST

Bug #81022	P_S.*.DIGEST_TEXT: improvements
Submitted:	9 Apr 2016 6:56	Modified:	15 Jul 2016 12:10
Reporter:	Simon Mudd (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Performance Schema	Severity:	S4 (Feature request)
Version:	8.0	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	digest, DIGEST_TEXT, Optimizer, performance_schema

Description:
The DIGEST shown in performance_schema is not consistent between major versions of MySQL. This is inconvenient if you start to compare statistics of different MySQL servers of different versions which can be quite common and in such an environment requires you to generate a digest that is common to all servers. This is rather wasteful.

The output format of the DIGEST_TEXT looks like a "query string with wild-card placeholder values", but due to formatting it is not really useful in that context.  It would be convenient to provide the output in such a format as this could then be used more easily with placeholder values to run a query with EXPLAIN to get further information on the query and it's workings. 

The extra spaces and quoting in the current DIGEST_TEXT occupy a lot of extra space which given the DIGEST_TEXT is quite short can lead to truncation which is not ideal.  So providing a better formatted, more compact representation of the DIGEST_TEXT would be useful.

How to repeat:
See above.

Suggested fix:
* Please make the DIGEST_TEXT consistent so that we don't need to generate a separate DIGEST and use that instead.
* Please provide the DIGEST_TEXT in a format that could be used with placeholder values directly.

Posted by developer:
 
Reported version value updated to reflect release name change from 5.8 to 8.0

Hello Simon,

Thank you for the feature request!

Thanks,
Umesh