Re: Long running compaction on huge hint table.

Thanks a lot Ben. Really appreciate your suggestions here. Regards, Varun Saluja Sent from my iPhone > On 21-May-2017, at 5:40 PM, Ben Slater wrote: > > My main suggestion would be to monitor the compaction backlog (pending > compactions). If the backlog is

Re: Long running compaction on huge hint table.

My main suggestion would be to monitor the compaction backlog (pending compactions). If the backlog is growing you need to either throttle writes, add more capacity to your cluster or possibly tune things. There is no simple answer to tuning but several good guides on the internet to help - this

Re: Long running compaction on huge hint table.

Hi All, Can someone Please suggest any recommendations for write intensive jobs Regards, Varun Saluja Sent from my iPhone > On 17-May-2017, at 3:52 PM, varun saluja wrote: > > Thanks Jeff. > > I have taken backup and did manual removal of hints with rolling restart. >

Re: Long running compaction on huge hint table.

Thanks Jeff. I have taken backup and did manual removal of hints with rolling restart. This brought cluster back in stable state. Can you Please share some recommendation for write intensive job . Actually ,we need to load dump from kafka to 3 node cassandra cluster . Write TPS per node will be

Re: Long running compaction on huge hint table.

You could also try stopping compaction, but that'll probably take a very long time as well Manually stopping each node (one at a time) and removing the sstables from only system.hints may be a better option. May want to take a snapshot if you're very concerned with that data. -- Jeff

Re: Long running compaction on huge hint table.

Hi, Truncatehints on nodes is running for more than 7 hours now. Nothing mentioned for same in sysemt logs even. And compaction stats reports increase in hints total bytes. pending tasks: 1 compaction type keyspace table completed totalunit progress

Re: Long running compaction on huge hint table.

Hi Jeff, I ran nodetool truncatehints on all nodes. Its running for more than 30 mins now. Status for compactstats reports same. pending tasks: 1 compaction type keyspace table completed totalunit progress Compaction system hints 11189118129

Re: Long running compaction on huge hint table.

Thanks a lot Jeff. You have explaned very well here. We have consitency as local quorum. Will follow truncate hints and repair therafter. I hope this brings cluster in stable state Thanks again. Regards, Varun Saluja Sent from my iPhone > On 16-May-2017, at 8:42 PM, Jeff Jirsa

Re: Long running compaction on huge hint table.

In Cassandra versions up to 3.0, hints are stored within a table, where the partition key is the host ID of the server for which the hints are stored. In such a data model, accumulating 800GB of hints is almost certain to cause very wide rows, which will in turn cause GC pressure when you

Re: Long running compaction on huge hint table.

You can control compaction with nodetool compactionthroughput but it will just slow down compaction and give resources for application, however it's not a fix. Sent from my iPhone > On May 16, 2017, at 9:15 AM, varun saluja wrote: > > Thanks Nitan. > Appreciate your help.

Re: Long running compaction on huge hint table.

Thanks Nitan. Appreciate your help. Can anyone suggest parameter change or something which can help in this situation. Regards, Varun Sent from my iPhone > On 16-May-2017, at 7:31 PM, Nitan Kainth wrote: > > If target table is dropped then you can remove its hints but

Re: Long running compaction on huge hint table.

If target table is dropped then you can remove its hints but there could be more hints from other table. If it has tables of your interest , then I won't comment on truncating hints. Size of hints depends on Kafka load , looks like you had overloaded the cluster during data load and not hints

Re: Long running compaction on huge hint table.

Hi Nitan, Rolling reatart did not helped. Same compaction status after restart. No other processes running here. These are dedicated cassandra nodes. Sent from my iPhone > On 16-May-2017, at 7:16 PM, Nitan Kainth wrote: > > Have you tried rolling restart? > Any agent or

Re: Long running compaction on huge hint table.

Thanks for update. I could see lot of io waits. This causing Gc and mutation drops . But as i mentioned we do not have high load for now. Hint replays are creating such high disk I/O. compactionstats show very high hint bytes like 780gb around. Is this normal? Just mentioning we are using flash

Re: Long running compaction on huge hint table.

Have you tried rolling restart? Any agent or other process hogging system? Sent from my iPhone > On May 16, 2017, at 7:58 AM, varun saluja wrote: > > Hi Nitan, > > Thanks for response. > > Yes, I could see mutation drops and increase count in system.hints. Is there > any

Re: Long running compaction on huge hint table.

Yes but it means data has to be replicated using repair. Hints are out come of unhealthy nodes, focus on finding why you have mutation drops, is it node, io or network etc. ideally you shouldn't see increasing hints all the time. Sent from my iPhone > On May 16, 2017, at 7:58 AM, varun saluja

Re: Long running compaction on huge hint table.

Hi, Could see intermittent GCs and mutation drops. *System log reports:* INFO [Service Thread] GCInspector.java:252 - ParNew GC in 3816ms. CMS Old Gen: 4663180720 -> 5520012520; Par Eden Space: 1718091776 -> 0; Par Survivor Space: 0 -> 214695936 INFO [ScheduledTasks:1]

Re: Long running compaction on huge hint table.

Hi Nitan, Thanks for response. Yes, I could see mutation drops and increase count in system.hints. Is there any way , i can proceed to truncate hints like using nodetool truncatehints. Regards, Varun Saluja On 16 May 2017 at 17:52, Nitan Kainth wrote: > Do you see

Re: Long running compaction on huge hint table.

Varun, This a message better for the user@ ML. Thanks, -Jason On Tue, May 16, 2017 at 3:41 AM, varun saluja wrote: > Hi Experts, > > We are facing issue on production cluster. Compaction on system.hint table > is running from last 2 days. > > > pending tasks: 1 >

Re: Long running compaction on huge hint table.

Do you see mutation drops? Select count from system.hints; is it increasing? Sent from my iPhone > On May 16, 2017, at 5:52 AM, varun saluja wrote: > > Hi Experts, > > We are facing issue on production cluster. Compaction on system.hint table is > running from last 2

Long running compaction on huge hint table.

Hi Experts, We are facing issue on production cluster. Compaction on system.hint table is running from last 2 days. pending tasks: 1 compaction type keyspace table completed total unit progress Compaction system hints 20623021829