MySQL Bugs: #70241: innodb_metrics::INDEX

Bug #70241	innodb_metrics::INDEX_MERGE defined but not set
Submitted:	4 Sep 2013 15:24	Modified:	18 Sep 2013 14:20
Reporter:	Inaam Rana (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: InnoDB storage engine	Severity:	S3 (Non-critical)
Version:	5.6.12, 5.6.14	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
information_schema.innodb_metrics has index_merge counter defined but it is not incremented in btr0btr.cc:

[irana@tw-mbp-irana:~/workspace/mysql-5.6/storage/innobase]grep -rIn INDEX_MERGE .
./include/srv0mon.h:311:	MONITOR_INDEX_MERGE,
./srv/srv0mon.cc:893:	 MONITOR_DEFAULT_START, MONITOR_INDEX_MERGE},
[irana@tw-mbp-irana:~/workspace/mysql-5.6/storage/innobase]

Also I think index_merge and index_split are not good names. Kind of implies as if we are counting some index level operations. index_page_merge and index_page_split are more appropriate IMO.

How to repeat:
see code

Suggested fix:
Update counter in btr0btr.cc

In fact, I have a patch against 5.6.12 which fixes this issue and also add some other relevant counters like index_page_discards, index_page_reorg etc. I'll be happy to submit the patch if someone can tell me the process.

Inaam,

thank you for the report. To contribute the fix you need to sign Oracle contributor agreement. All steps described in the "Contribution" tab of the bug report. Let us know if you have any issues with this description.

I have signed and sent the OCA. I'll upload the patch file next.

Patch for extra innodb_metrics for index ops

Attachment: index_metrics-5.6.patch (application/octet-stream, text), 7.40 KiB.

Added changelog entry to 5.6.15:

"The "information_schema.innodb_metrics" "index_merge" counter was not
incremented in "btr0btr.cc". This patch also introduces new counters
("index_page_reorg_attempts", "index_page_reorg_successful" and
"index_page_discards") and renames the "index_merges" counter to
""index_page_merge_attempts"" to distinguish it from the
"index_page_merge_successful" counter."

Thank you for the bug report.

5.6$ bzr log -r 5448
------------------------------------------------------------
revno: 5448
committer: bin.x.su@oracle.com
branch nick: mysql-5.6
timestamp: Fri 2013-09-13 10:08:28 +0800
message:
  BUG 17409657 - INNODB_METRICS::INDEX_MERGE DEFINED BUT NOT SET
  
  1. Information_schema.innodb_metrics has index_merge counter defined but
     it is not incremented in btr0btr.cc.
  
  2. Users need some other relevant counters like index_page_discards,
     index_page_reorg etc.
  
  So index_page_merge_attempts which replace index_merges is introduced to
  distinguish from index_page_merge_successful, also, index_page_reorg_attempts, 
  index_page_reorg_successful and index_page_discards are introduced too.
  
  Original patch is provided by Inaam.
  
  Approved by Jimmy, rb#3297