Raven consistently using 20% of CPU time

[Mircea Chirea]

During the tests I've run with Raven on Azure I've noticed something interesting - one of the servers is consistently using 20% of the CPU time, while the other is using only 2%. This is when idle; heck the server in question, while being a master, is not directly referenced by any apps and I guess it only gets round-robin read traffic, which is VERY low. Here's a New Relic screenshot: http://imgur.com/NhUSsxw

How can I even begin to diagnose this? I certainly don't want to rebuild the VM, as I've done that too many times :D

[Oren Eini (Ayende Rahien)]

Being the master, this is the one that is handling all of the writes, indexing, replication to other nodes, etc.

You can look at the logs and see what it is doing.

On Wed, May 8, 2013 at 11:23 PM, Mircea Chirea <chirea...@gmail.com> wrote:

During the tests I've run with Raven on Azure I've noticed something interesting - one of the servers is consistently using 20% of the CPU time, while the other is using only 2%. This is when idle; heck the server in question, while being a master, is not directly referenced by any apps and I guess it only gets round-robin read traffic, which is VERY low. Here's a New Relic screenshot: http://imgur.com/NhUSsxw

How can I even begin to diagnose this? I certainly don't want to rebuild the VM, as I've done that too many times :D

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[Mircea Chirea]

Well it is a master (M-M replication), but this isn't the one referenced in the apps. It has that load even if I remove all references to it :|

[Oren Eini (Ayende Rahien)]

That sounds strange, can you look at the logs?

[Kijana Woodard]

I remember a similar behavior. The source of the problem turned out to be conflict documents we weren't handling, iirc. Adding a server side conflict resolver made it go away.

Any conflicted docs?

[Mircea Chirea]

No, no conflicts. I do have a resolver but I don't think it ever had the opportunity to do any work.

[Mircea Chirea]

Nothing unusual. Just a replicated doc every few seconds, triggering indexing, but that's it. The database has about 1.5k docs and since the master does indexing without 20% load, I doubt it's that :|

[Oren Eini (Ayende Rahien)]

Can you send the logs?

Can you do a dump and look at the stack traces?

[Mircea Chirea]

Updated to 2360 and it's at about 7% now; it looks like it spikes on replication, regardless of the amount of replicated docs. I consider that to be fine.

[Karl Cassar]

I think this is related to the same problem I am experiencing, although I am not using Master-Master replication.  Switching off all clients to the server, Raven.Server still uses 25 - 50% and sometimes even 100%, with no apparent load on the server.  This is happening on two different instances of Raven.Server I am using.

Regards,

Karl

[Oren Eini (Ayende Rahien)]

What happen if you disable replication?

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