[SERVER-17121] Throughput Dropout on mongo-sim insert-update-query workload with WiredTiger Created: 29/Jan/15  Updated: 17/Mar/15  Resolved: 19/Feb/15

Status: Closed
Project: Core Server
Component/s: Performance, Storage
Affects Version/s: 3.0.0-rc7
Fix Version/s: 3.0.0-rc9, 3.1.0

Type: Bug Priority: Critical - P2
Reporter: David Daly Assignee: Michael Cahill (Inactive)
Resolution: Done Votes: 1
Labels: 28qa
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File 10thread2client.png     PNG File Screen Shot 2015-01-29 at 4.04.17 PM.png     PNG File questions.png     PNG File rc9.png     PNG File rc9mongolog.png     PNG File stuck.png     PNG File walk.png    
Issue Links:
Related
is related to SERVER-17115 insert workload stalls on oplog trunc... Closed
Backwards Compatibility: Fully Compatible
Operating System: ALL
Backport Completed:
Steps To Reproduce:

mongod --dbpath /data --storageEngine=wiredTiger
mongo-sim -w workloads/insert_update_query -e 10000000 -t 100 -c 7

Running on linux with SSD.

Running on RC7 and https://mci.10gen.com/task/mongodb_mongo_v3.0_linux_64_b70d96e06c2c3fa86d95f6719ab1815a98db77a9_15_01_29_16_47_02_compile_linux_64

Participants:

 Description   

Running mongo-sim insert-update-query workload experiencing periods of very low throughput.

This reproduces both on RC7 and latest in v3.0 (b70d96e06c2c3fa86d95f6719ab1815a98db77a9)

mongo-sim is here, with instructions to build: https://github.com/10gen/mongo-sim



 Comments   
Comment by Ramon Fernandez Marina [ 19/Feb/15 ]

Ticket has been fixed by the latest WT drop in master as per entry in NEWS.MONGODB:

commit 0d85a9716b786de5fc90c00fb31765ade8aefd1f
Author: Michael Cahill <michael.cahill@wiredtiger.com>
Date:   Wed Feb 11 17:48:03 2015 +1100
 
    Check if a page was recently split before doing forced eviction.  We used to do this, but it got lost in a recent reorg of
 __wt_page_release.  This change should mean that after an in-memory split, application threads that are appending have time t
o move to the new page at the end of the tree, rather than getting stuck trying to force out a page.
 
    SERVER-16938, SERVER-17121

Fix also backported to v3.0.

Comment by Daniel Pasette (Inactive) [ 19/Feb/15 ]

fix will come in next WT drop.

Comment by David Daly [ 17/Feb/15 ]

Missed the mongod log file on earlier graph. Here's the two key lines from it.

bruce.lucas@10gen.com does A-B, C-D look like SERVER-16662 to you?

Comment by Ben Becker [ 29/Jan/15 ]

Note that you can run the command listed in the repro steps, or:

./insert_update_query-sim -e 10000000 -t 100 -c 7

This stand-alone binary can be distributed with minimal shared lib deps, as long as it was built on a machine with a static build of libmongoc.

Comment by David Daly [ 29/Jan/15 ]

Reproduced on RC6 also.

Comment by David Daly [ 29/Jan/15 ]

May be the same as SERVER-17115. Putting info here.

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