Pending tasks are not a queue, they are an estimation of the amount of work it
would take to reach a perfect compaction point, but the compactions aren’t
independent from one another. For instance, with LCS you may have a compaction
from L0 -> L1, which triggers a L1 -> L2 compaction. You can’t do them in
parallel because one depends on the other.
> On Sep 21, 2017, at 3:10 PM, ZAIDI, ASAD A wrote:
>
> Hello Folks,
>
> Is it possible to findout detail of those 275 pending tasks compactionstats
> command output is showing?
> I’ve bumpedup concurrent_compactors to 25 though not all threads are
> compacting, only 8 threads are being used so i’m wondering how can I utilize
> all configured concurrent compactors when there are still pending tasks?
>
>
>
> [cassandra@server]$ nodetool compactionstats -H
> pending tasks: 275
> id compaction type keyspace
> table completed totalunit progress
>64c55e50-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> usrcnt_location_by_hour70.47 MB 178.29 MB bytes 39.52%
>65930e90-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> visi_det_rollup87.46 MB 208.54 MB bytes 41.94%
>73c34250-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> visi_det_rollup 3.1 MB 122.41 MB bytes 2.53%
>d4e2cde0-9f16-11e7-94ce-0fe8b18d4e6cCompaction corporate
>timing_by_account 1.64 GB 5.96 GB bytes 27.59%
>6a430210-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> stream_host_etl 127.05 MB 162.78 MB bytes 78.05%
>6c997530-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> det_rollup40.44 MB 131.33 MB bytes 30.79%
>59fc4a60-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> det_rollup 180.48 MB 250.69 MB bytes 72.00%
>607739e0-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> det_rollup 131.36 MB 256.18 MB bytes 51.28%
>659817a0-9f17-11e7-94ce-0fe8b18d4e6cCompaction corporate
> station_data 108 MB 267.68 MB bytes 40.35%
> Active compaction remaining time :n/a
>
> ==
>
> [cassandra@server]$ nodetool tpstats
>
> Pool NameActive Pending Completed Blocked All
> time blocked
> MutationStage 1 0 200764219 0
> 0
> ReadStage 0 0 0 0
> 0
> RequestResponseStage 0 0 37 0
> 0
> ReadRepairStage 0 0 0 0
> 0
> CounterMutationStage 0 0 0 0
> 0
> HintedHandoff 0 0 16 0
> 0
> MiscStage 0 0 0 0
> 0
> CompactionExecutor8 8 19129 0
> 0
> MemtableReclaimMemory 0 0 14586 0
> 0
> PendingRangeCalculator0 0 6 0
> 0
> GossipStage 0 0 75457 0
> 0
> MigrationStage0 0 2558 0
> 0
> MemtablePostFlush 1 1 15908 0
> 0
> ValidationExecutor0 0 0 0
> 0
> Sampler 0 0 0 0
> 0
> MemtableFlushWriter 1 1 14573 0
> 0
> InternalResponseStage 0 0 0 0
> 0
> AntiEntropyStage 0 0 0 0
> 0
> CacheCleanupExecutor 0 0 0 0
> 0
>
> Message type Dropped
> READ 0
> RANGE_SLICE 0
> _TRACE 0
> MUTATION 0
> COUNTER_MUTATION 0
> REQUEST_RESPONSE 0
> PAGED_RANGE 0
> READ_REPAIR 0
>
>
>
> Thanks/Asad
