topic How to extract and compute fields from a MongoDB log? in Splunk Search

How to extract and compute fields from a MongoDB log?

kchongo — Thu, 06 Oct 2016 21:39:36 GMT

Hello,

I am new to Splunk, can you help me figure out to extract and fields from logs that look like the below

2016-10-06T21:22:15.285+0000 I COMMAND  [conn337418] command PersoTestServiceDB.$cmd command: update { update: "Test_Stage", updates: 1000, ordered: false, shardVersion: [ Timestamp 0|0, ObjectId('000000000000000000000000') ] } keyUpdates:0 writeConflicts:0 numYields:0 reslen:232 locks:{ Global: { acquireCount: { r: 2000, w: 2000 } }, Database: { acquireCount: { w: 2000 } }, Collection: { acquireCount: { w: 1000 } }, Metadata: { acquireCount: { w: 1000 } }, oplog: { acquireCount: { w: 1000 } } } protocol:op_command 175ms

The above block is from a MongoDB log file, I am mostly interested in extracting the last field and then sort by the field with the largest value in "ms". I am trying to see how long queries take to complete on average as well as identify the long running queries from the logs. I would also like to list the long running query next to the query time when sorted.

Your assistance is appreciated. Thanks.

Re: How to extract and compute fields from a MongoDB log?

sundareshr — Thu, 06 Oct 2016 22:42:13 GMT

If your data is already in Splunk, you could try this in your search
*UPDATED*

base search  NOT "sleeping" | rex "(?<dur>\d+)ms" | eventstats avg(dur) as avg_dur | sort - dur | table _time _raw dur avg_dur

Re: How to extract and compute fields from a MongoDB log?

kchongo — Fri, 07 Oct 2016 00:22:57 GMT

Thanks this looks good, now one more thing; how can I strip out a log entry below that is counting sleep time; its adding to the average calculation and when sorted appears at the top of the results.

2016-10-07T00:11:56.366+0000 I SHARDING [LockPinger] cluster mongodbhost1a:27019,mongodbhost1b:27019,mongodbhost1c:27022 pinged successfully at 2016-10-07T00:11:55.615+0000 by distributed lock pinger 'mongodbhost1a:27019,mongodbhost1b:27019,mongodbhost1c:27022/mongodbhost4a:27018:1469673136:466927433', sleeping for 30000ms

Re: How to extract and compute fields from a MongoDB log?

sundareshr — Fri, 07 Oct 2016 02:18:30 GMT

Try the updated search

Re: How to extract and compute fields from a MongoDB log?

kchongo — Fri, 07 Oct 2016 14:44:06 GMT

Thanks, this gives me what I am looking for. I can build more around this starting point.

I noticed that the time seems to be shown on the graph on reverse, the latest times are the one closest to the x and y intersection; should this be the other way round? How can I fix this