Download - Diagnostics and Debugging
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Principal Solutions Architect, MongoDB
Asya Kamsky
#MongoDBdays @asya999 #askAsya
Diagnostics and Debugging
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Principal Solutions Architect, MongoDB
Asya Kamsky
#MongoDBdays @asya999 #askAsya
Diagnostics and Debugging
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Understanding Crime Scene
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“Data! Data! Data!
I can't make bricks without clay.”
-- Sherlock Holmes,
The Adventure of the Copper Beeches
9
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Gathering Data
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“It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”
-- Sherlock Holmes, A Scandal in Bohemia
11
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“There is nothing like first-hand evidence.” -- Sherlock Holmes, A Study in Scarlet
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Available Tools:
% mongostat
% mongotop
> db.currentOp( ), db.serverStatus( )
> rs.status( )
> sh.status( )
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Available Tools:
% mongostat
% mongotop
> db.currentOp( ), db.serverStatus( )
> rs.status( )
> sh.status( )
MongoDB Management Service (MMS)
Monitoring
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Available Tools:
MongoDB Management Service (MMS)
Monitoring
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Available Tools:
MongoDB Management Service (MMS)
Monitoring
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Available Tools:
MongoDB Management Service (MMS)
Monitoring
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Available Tools:
MongoDB Management Service (MMS)
Monitoring
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mongod logs
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mongod logs
Tue Jul 30 19:15:27.898 [conn2] querytest.docs query: { query: { _id: { $gt:ObjectId('51da44a8a4435e3d7174b696') }}, orderby: { ts: 1.0 } } ntoreturn:10ntoskip:0 nscanned:9235093scanAndOrder:1 keyUpdates:0 numYields:5locks(micros) r:6919962 nreturned:1reslen:360 3578ms
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mongod logs
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mongod logs
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"It is of the highest importance ... to be able to recognize, out of a number of facts, which are incidental and which vital. "
Sherlock Holmes, The Reigate Puzzle
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https://github.com/rueckstiess/mtools
by Thomas Ruckstieß
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mtools
• mloginfo
• mlogfilter
• mplotqueries
• mlogvis
• mlaunch
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mtools
• mloginfo
• mlogfilter
• mplotqueries
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mloginfo
source: logs/mongodb.log.2014-05-04T15-52-59 start: 2014 May 02 00:29:21 end: 2014 May 04 15:52:59date format: iso8601-local length: 17091234 binary: mongod version: 2.6.0
------------------------------------------
source: logs/mongodb.log.2014-05-04T15-53-06 start: 2014 May 02 00:29:25 end: 2014 May 04 15:53:06date format: iso8601-local length: 13696471 binary: mongod version: 2.6.0
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
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mplotqueries$ mplotqueries --helpusage: mplotqueries [OPTIONS] [logfile [logfile ...]]
A script to plot various information from logfiles. ...
optional arguments:
--type {nscanned/n,rsstate,connchurn,durline,histogram,range,scatter,event} type of plot (default=scatter with --yaxis duration)
--group GROUP specify value to group on. All basic plot types can group on 'namespace', 'operation', 'thread', 'pattern' ...
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"... what is out of the common is usually a guide rather than a hindrance." — Sherlock Holmes, A Study in Scarlet
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The Adventure of the Missing Three-Quarter (Indexes)
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$ mloginfo firstmongo.log source: firstmongo.log start: 2014 Jun 10 11:19:54 end: 2014 Jun 17 17:14:15date format: iso8601-local length: 14170668 binary: mongod version: 2.6.1
mloginfo firstmongo.log --queries
mloginfo
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$ mloginfo firstmongo.log source: firstmongo.log start: 2014 Jun 10 11:19:54 end: 2014 Jun 17 17:14:15date format: iso8601-local length: 14170668 binary: mongod version: 2.6.1
mloginfo firstmongo.log –-queriesnamespace pattern count max (ms) mean (ms) 95%-ile (ms) sum (ms)db1.request {"requestSender": 1} 29 350161 93828 339441.2 2721018db1.request {"curRoute": 1,"isAdv": 1 } 169 9585 3942 6324.2 666302db1.report {"deliveryTime": 1} 9 111421 71536 106609.4 643829db2.report {"deliveryTime": 1} 10 85267 60363 81508.15 603634db3.report {"deliveryTime": 1} 10 72071 53062 70781.3 530624db1.pending {"sentTime": 1, "status": 1} 9 108734 38013 88470.4 342117
mloginfo
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms2014-06-17T17:13:47.607 [conn1569990] query db2.coll query: { time: { $lt: "2014-06-17 17:14:05", $gte: "2014-06-17 17:05:05" }, status: 8 } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:2057564 nscannedObjects:2057564 keyUpdates:0 numYields:5008 locks(micros) r:11557172 nreturned:56 reslen:18745 13086ms
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms2014-06-17T17:13:47.607 [conn1569990] query db2.coll query: { time: { $lt: "2014-06-17 17:14:05", $gte: "2014-06-17 17:05:05" }, status: 8 } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:2057564 nscannedObjects:2057564 keyUpdates:0 numYields:5008 locks(micros) r:11557172 nreturned:56 reslen:18745 13086ms
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mplotqueries
% mplotqueries firstmongo.log --type nscanned/n2014-06-17T17:13:34.235 [conn1569841] query db1.coll query: { time: { $lt: "2014-06-17 17:13:31", $gte: "2014-06-17 17:04:31" } } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:5169727 nscannedObjects:5169727 keyUpdates:0 numYields:12492 locks(micros) r:37736571 nreturned:72 reslen:32707 30129ms2014-06-17T17:13:47.607 [conn1569990] query db2.coll query: { time: { $lt: "2014-06-17 17:14:05", $gte: "2014-06-17 17:05:05" }, status: 8 } planSummary: COLLSCAN ntoreturn:0 ntoskip:0 nscanned:2057564 nscannedObjects:2057564 keyUpdates:0 numYields:5008 locks(micros) r:11557172 nreturned:56 reslen:18745 13086ms
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The Sign of Four (Shards)
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% mplotqueries updates?.log
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% mplotqueries updates?.log
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% mplotqueries updates?.log
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% mplotqueries updates?.log
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% mplotqueries updates?.log
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59
"Eliminate all other factors, and the one which remains must be the truth."
Sherlock Holmes -The Sign of Four
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The Case of Identity
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% mplotqueries –type histogram –group namespace –bucketSize 3600
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The Stockbroker's Clerk's Query
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% mplotqueries –type connchurn
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"We balance probabilities and choose the most likely. It is the scientific use of the imagination." Sherlock Holmes, The Hound of the Baskervilles
With profound thanks to: Sir Arthur Conan Doyle (1859-1930)
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MongoDB, Inc.
Asya Kamsky
#MongoDBdays @asya999
Thank You
http://askasya.com/
http://www.kamsky.org/