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 <az1...@att.com> 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 total unit progress > 64c55e50-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > usrcnt_location_by_hour 70.47 MB 178.29 MB bytes 39.52% > 65930e90-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > visi_det_rollup 87.46 MB 208.54 MB bytes 41.94% > 73c34250-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > visi_det_rollup 3.1 MB 122.41 MB bytes 2.53% > d4e2cde0-9f16-11e7-94ce-0fe8b18d4e6c Compaction corporate > timing_by_account 1.64 GB 5.96 GB bytes 27.59% > 6a430210-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > stream_host_etl 127.05 MB 162.78 MB bytes 78.05% > 6c997530-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > det_rollup 40.44 MB 131.33 MB bytes 30.79% > 59fc4a60-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > det_rollup 180.48 MB 250.69 MB bytes 72.00% > 607739e0-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > det_rollup 131.36 MB 256.18 MB bytes 51.28% > 659817a0-9f17-11e7-94ce-0fe8b18d4e6c Compaction corporate > station_data 108 MB 267.68 MB bytes 40.35% > Active compaction remaining time : n/a > > ============== > > [cassandra@server]$ nodetool tpstats > > Pool Name Active 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 > CompactionExecutor 8 8 19129 0 > 0 > MemtableReclaimMemory 0 0 14586 0 > 0 > PendingRangeCalculator 0 0 6 0 > 0 > GossipStage 0 0 75457 0 > 0 > MigrationStage 0 0 2558 0 > 0 > MemtablePostFlush 1 1 15908 0 > 0 > ValidationExecutor 0 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
