Debugging oplog hints

[dandv]

The biggest performance bottleneck we're experiencing in our app right not is that oplog is disabled, despite setting up a replica set as described here.

It would be great if Kadira drilled down into the reasons for that, e.g.

• no MONGO_OPLOG_URL env var
• query with limit or skip but without sort
• special operators

[arunoda]

Yes. Dan.

This is possible with our upcoming query analyzer which hints indexes. I
will add this kind of discovery as well.

On Wednesday, June 11, 2014, Dan Dascalescu notifications@github.com
wrote:

The biggest performance bottleneck we're experiencing in our app right not
is that oplog is disabled. It would be great if Kadira drilled down into
the reasons for that, e.g.

• no MONGO_OPLOG_URL env var
• query with limit or skip but without sort
  Polling driver is used instead of oplog when specifying limit without sort meteor/meteor#1947
• special operators

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Arunoda Susiripala
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[arunoda]

I think. we can simply show the reason and how to fix it directly on the trace.

[arunoda]

Started to work on this feature: https://github.com/meteorhacks/kadira/tree/check-for-oplog

[dandv]

Awesome! I managed to get oplog working, but it still takes a LOT of time:

[arunoda]

Btw.

Your query takes time
Add some relavent indexes

On Sunday, June 15, 2014, Dan Dascalescu notifications@github.com wrote:

Awesome! I managed to get oplog working, but it still takes a LOT of time:

[image: image]
https://cloud.githubusercontent.com/assets/33569/3279735/0d0075d0-f414-11e3-92b4-622e3783769d.png

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Arunoda Susiripala

@arunoda http://twitter.com/arunoda
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[arunoda]

Hope, we can close this now: https://kadira.io/academy/optimize-your-app-for-oplog/

[dandv]

Indeed, I needed a composite index, which is now added. Need to check the oplog usage, but let's close for now. Great work on the oplog optimization tips!

[arunoda]

Cool. Thanks.

---

Arunoda Susiripala

@arunoda http://twitter.com/arunoda
http://gplus.to/arunodahttps://github.com/arunoda
http://www.linkedin.com/in/arunoda

On Thu, Jun 19, 2014 at 11:36 PM, Dan Dascalescu notifications@github.com
wrote:

Closed #1 #1.

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[dandv]

BTW, https://kadira.io/blog/ should perhaps include the oplog article?

[arunoda]

It's on academy.

On Friday, June 20, 2014, Dan Dascalescu notifications@github.com wrote:

BTW, https://kadira.io/blog/ should perhaps include the oplog article?

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Arunoda Susiripala

@arunoda http://twitter.com/arunoda
http://gplus.to/arunodahttps://github.com/arunoda
http://www.linkedin.com/in/arunoda