another note on this, i stopped my client and after about 35 minutes the compaction did complete, no more pending in compaction-pool. however the Index, Data, and Filter files still exist with lots of data in them. "Compact" files exist for all but 4 of the Data files - these "compact" files are zero length.
thx! On Thu, 2009-12-03 at 15:40 -0800, B. Todd Burruss wrote: > in my situation it seems like the compaction process is being starved. > i'm hitting the server hard for the last 45 minutes and the compaction > pool is sitting at 1 active, 25 pending, and 7 completed. it has been > at 1 active and 7 completed for about 20 minutes. the pending have been > growing steadily since then. and as i was typing it finally finished > another compaction, so they must be just taking forever. > > snapshots of nodeprobe and iostats follow: > > Pool Name Active Pending Completed > FILEUTILS-DELETE-POOL 0 0 116 > MESSAGING-SERVICE-POOL 0 0 0 > STREAM-STAGE 0 0 0 > RESPONSE-STAGE 0 0 0 > ROW-READ-STAGE 1 4 8652560 > LB-OPERATIONS 0 0 0 > COMMITLOG 1 0 14695623 > MESSAGE-DESERIALIZER-POOL 0 0 0 > GMFD 0 0 0 > LB-TARGET 0 0 0 > CONSISTENCY-MANAGER 0 0 0 > ROW-MUTATION-STAGE 1 1 14692604 > MESSAGE-STREAMING-POOL 0 0 0 > LOAD-BALANCER-STAGE 0 0 0 > FLUSH-SORTER-POOL 0 0 28 > MEMTABLE-POST-FLUSHER 0 0 28 > COMPACTION-POOL 1 25 7 > FLUSH-WRITER-POOL 0 0 28 > HINTED-HANDOFF-POOL 0 0 0 > > > avg-cpu: %user %nice %system %iowait %steal %idle > 61.85 0.00 26.68 7.73 0.00 3.74 > > Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn > sda 246.00 11456.00 18528.00 11456 18528 > sda2 23074.00 20.50 1854.00 20 1854 > sda1 0.00 0.00 0.00 0 0 > > > > > On Thu, 2009-12-03 at 17:05 -0600, Jonathan Ellis wrote: > > Thanks for looking into this. Doesn't seem like there's much > > low-hanging fruit to make compaction faster but I'll keep that in the > > back of my mind. > > > > -Jonathan > > > > On Thu, Dec 3, 2009 at 4:58 PM, Freeman, Tim <[email protected]> wrote: > > >>So this is working as designed, but the design is poor because it > > >>causes confusion. If you can open a ticket for this that would be > > >>great. > > > > > > Done, see: > > > > > > https://issues.apache.org/jira/browse/CASSANDRA-599 > > > > > >>What does iostat -x 10 (for instance) say about the disk activity? > > > > > > rkB/s is consistently high, and wkB/s varies. This is a typical entry > > > with wkB/s at the high end of its range: > > > > > >>avg-cpu: %user %nice %sys %iowait %idle > > >> 1.52 0.00 1.70 27.49 69.28 > > >> > > >>Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s > > >>avgrq-sz avgqu-sz await svctm %util > > >>sda 3.10 3249.25 124.08 29.67 26299.30 26288.11 13149.65 > > >>13144.06 342.04 17.75 92.25 5.98 91.92 > > >>sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 > > >> 0.00 0.00 0.00 0.00 0.00 > > >>sda2 3.10 3249.25 124.08 29.67 26299.30 26288.11 13149.65 > > >>13144.06 342.04 17.75 92.25 5.98 91.92 > > >>sda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 > > >> 0.00 0.00 0.00 0.00 0.00 > > > > > > and at the low end: > > > > > >>avg-cpu: %user %nice %sys %iowait %idle > > >> 1.50 0.00 1.77 25.80 70.93 > > >> > > >>Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s > > >>avgrq-sz avgqu-sz await svctm %util > > >>sda 3.40 817.10 128.60 17.70 27828.80 6600.00 13914.40 3300.00 > > >> 235.33 6.13 56.63 6.21 90.81 > > >>sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 > > >> 0.00 0.00 0.00 0.00 0.00 > > >>sda2 3.40 817.10 128.60 17.70 27828.80 6600.00 13914.40 3300.00 > > >> 235.33 6.13 56.63 6.21 90.81 > > >>sda3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 > > >> 0.00 0.00 0.00 0.00 0.00 > > > > > > Tim Freeman > > > Email: [email protected] > > > Desk in Palo Alto: (650) 857-2581 > > > Home: (408) 774-1298 > > > Cell: (408) 348-7536 (No reception business hours Monday, Tuesday, and > > > Thursday; call my desk instead.) > > > > > > > > > -----Original Message----- > > > From: Jonathan Ellis [mailto:[email protected]] > > > Sent: Thursday, December 03, 2009 2:45 PM > > > To: [email protected] > > > Subject: Re: Persistently increasing read latency > > > > > > On Thu, Dec 3, 2009 at 4:34 PM, Freeman, Tim <[email protected]> wrote: > > >>>Can you tell if the system is i/o or cpu bound during compaction? > > >> > > >> It's I/O bound. It's using ~9% of 1 of 4 cores as I watch it, and all > > >> it's doing right now is compactions. > > > > > > What does iostat -x 10 (for instance) say about the disk activity? > > > > >
