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From Віталій Тимчишин <tiv...@gmail.com>
Subject Re: persistent compaction issue (1.1.4 and 1.1.5)
Date Thu, 20 Sep 2012 05:35:09 GMT
I did see problems with schema agreement on 1.1.4, but they did go away
after rolling restart (BTW: it would be still good to check describe schema
for unreachable). Same rolling restart helped to force compactions after
moving to Leveled compaction. If your compactions still don't go, you can
try removing *.json files from the data directory of the stopped node to
force moving all SSTables to level0.

Best regards, Vitalii Tymchyshyn

2012/9/19 Michael Kjellman <mkjellman@barracuda.com>

> Potentially the pending compactions are a symptom and not the root
> cause/problem.
>
> When updating a 3rd column family with a larger sstable_size_in_mb it
> looks like the schema may not be in a good state
>
> [default@xxxx] UPDATE COLUMN FAMILY screenshots WITH
> compaction_strategy=LeveledCompactionStrategy AND
> compaction_strategy_options={sstable_size_in_mb: 200};
> 290cf619-57b0-3ad1-9ae3-e313290de9c9
> Waiting for schema agreement...
> Warning: unreachable nodes 10.8.30.102The schema has not settled in 10
> seconds; further migrations are ill-advised until it does.
> Versions are UNREACHABLE:[10.8.30.102],
> 290cf619-57b0-3ad1-9ae3-e313290de9c9:[10.8.30.15, 10.8.30.14, 10.8.30.13,
> 10.8.30.103, 10.8.30.104, 10.8.30.105, 10.8.30.106],
> f1de54f5-8830-31a6-9cdd-aaa6220cccd1:[10.8.30.101]
>
>
> However, tpstats looks good. And the schema changes eventually do get
> applied on *all* the nodes (even the ones that seem to have different
> schema versions). There are no communications issues between the nodes and
> they are all in the same rack
>
> root@xxxx:~# nodetool tpstats
> Pool Name                    Active   Pending      Completed   Blocked
> All time blocked
> ReadStage                         0         0        1254592         0
>             0
> RequestResponseStage              0         0        9480827         0
>             0
> MutationStage                     0         0        8662263         0
>             0
> ReadRepairStage                   0         0         339158         0
>             0
> ReplicateOnWriteStage             0         0              0         0
>             0
> GossipStage                       0         0        1469197         0
>             0
> AntiEntropyStage                  0         0              0         0
>             0
> MigrationStage                    0         0           1808         0
>             0
> MemtablePostFlusher               0         0            248         0
>             0
> StreamStage                       0         0              0         0
>             0
> FlushWriter                       0         0            248         0
>             4
> MiscStage                         0         0              0         0
>             0
> commitlog_archiver                0         0              0         0
>             0
> InternalResponseStage             0         0           5286         0
>             0
> HintedHandoff                     0         0             21         0
>             0
>
> Message type           Dropped
> RANGE_SLICE                  0
> READ_REPAIR                  0
> BINARY                       0
> READ                         0
> MUTATION                     0
> REQUEST_RESPONSE             0
>
> So I'm guessing maybe the different schema versions may be potentially
> stopping compactions? Will compactions still happen if there are different
> versions of the schema?
>
>
>
>
>
> On 9/18/12 11:38 AM, "Michael Kjellman" <mkjellman@barracuda.com> wrote:
>
> >Thanks, I just modified the schema on the worse offending column family
> >(as determined by the .json) from 10MB to 200MB.
> >
> >Should I kick off a compaction on this cf now/repair?/scrub?
> >
> >Thanks
> >
> >-michael
> >
> >From: Віталій Тимчишин <tivv00@gmail.com<mailto:tivv00@gmail.com>>
> >Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>"
> ><user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> >To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>"
> ><user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> >Subject: Re: persistent compaction issue (1.1.4 and 1.1.5)
> >
> >I've started to use LeveledCompaction some time ago and from my
> >experience this indicates some SST on lower levels than they should be.
> >The compaction is going, moving them up level by level, but total count
> >does not change as new data goes in.
> >The numbers are pretty high as for me. Such numbers mean a lot of files
> >(over 100K in single directory) and a lot of thinking for compaction
> >executor to decide what to compact next. I can see numbers like 5K-10K
> >and still thing this is high number. If I were you, I'd increase
> >sstable_size_in_mb 10-20 times it is now.
> >
> >2012/9/17 Michael Kjellman
> ><mkjellman@barracuda.com<mailto:mkjellman@barracuda.com>>
> >Hi All,
> >
> >I have an issue where each one of my nodes (currently all running at
> >1.1.5) is reporting around 30,000 pending compactions. I understand that
> >a pending compaction doesn't necessarily mean it is a scheduled task
> >however I'm confused why this behavior is occurring. It is the same on
> >all nodes, occasionally goes down 5k pending compaction tasks, and then
> >returns to 25,000-35,000 compaction tasks pending.
> >
> >I have tried a repair operation/scrub operation on two of the nodes and
> >while compactions initially happen the number of pending compactions does
> >not decrease.
> >
> >Any ideas? Thanks for your time.
> >
> >Best,
> >michael
> >
> >
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> >Barracuda Networks solutions.
> >
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> >
> >
> >
> >
> >
> >
> >
> >--
> >Best regards,
> > Vitalii Tymchyshyn
> >
> >'Like' us on Facebook for exclusive content and other resources on all
> >Barracuda Networks solutions.
> >
> >Visit http://barracudanetworks.com/facebook
> >
> >
> >
> >
>
>
> 'Like' us on Facebook for exclusive content and other resources on all
> Barracuda Networks solutions.
>
> Visit http://barracudanetworks.com/facebook
>
>
>
>
>


-- 
Best regards,
 Vitalii Tymchyshyn

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