[DOCS-7979] Size and count in collection stats are persisted during checkpoints in WiredTiger Created: 26/May/16  Updated: 11/Jan/17  Resolved: 02/Aug/16

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: 01112017-cleanup

Type: Task Priority: Major - P3
Reporter: Daniel Pasette (Inactive) Assignee: Ravind Kumar (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
related to DOCS-8478 Size and Count Accuracy after Unexpec... Closed
is related to SERVER-24266 Large discrepancy in SizeStorer after... Backlog
is related to DOCS-5682 Document that the size and count in c... Closed
Participants:
Days since reply: 7 years, 25 weeks, 1 day ago

 Description   

https://docs.mongodb.com/manual/reference/command/collStats/#unexpected-shutdown-and-count

I reported some inaccurate information via DOCS-5682, saying that size and count is updated every 1000 document writes. As clarified in SERVER-24266, we update the in-memory cache every 1000 document writes, but the updates only become persistent when WiredTigerKVEngine::syncSizeInfo is called, most commonly every 60 seconds as part of WiredTigerKVEngine::haveDropsQueued.

This means that number can drift much more in the event of an unclean shutdown (as much as 60 seconds worth of writes).



 Comments   
Comment by Githook User [ 23/Aug/16 ]

Author:

{u'username': u'rkumar-mongo', u'name': u'ravind', u'email': u'ravind.kumar@10gen.com'}

Message: DOCS-8478: Size and Count accuracy in WT after unexpected shutdown

Extension of DOCS-7979, applied to count dbcommand, dbstats and helper methods

Signed-off-by: kay <kay.kim@10gen.com>
Branch: master
https://github.com/mongodb/docs/commit/850e312d54243be5c4d154cd1ce46319fe9953b4

Comment by Ravind Kumar (Inactive) [ 02/Aug/16 ]

linda.qin, I've created DOCS-8478 to track the requested changes.

Comment by Linda Qin [ 02/Aug/16 ]

Reopen this ticket.. Some other documents related to stats/count need to be updated as well:

Comment by Githook User [ 13/Jun/16 ]

Author:

{u'username': u'rkumar-mongo', u'name': u'ravind', u'email': u'ravind.kumar@10gen.com'}

Message: DOCS-7979: Unclean shutdown may cause 60 seconds of drift in collStats or count

Signed-off-by: kay <kay.kim@10gen.com>
Branch: master
https://github.com/mongodb/docs/commit/2253bf276c778540fcdfa87105f69999da3d31e9

Comment by Ravind Kumar (Inactive) [ 13/Jun/16 ]

https://github.com/mongodb/docs/pull/2644

Generated at Thu Feb 08 07:55:24 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.