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https://issues.apache.org/jira/browse/KUDU-2701?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Wong resolved KUDU-2701.
-------------------------------
Resolution: Fixed
Fix Version/s: 1.9.0
Will fixed this with 3e3bd1ccbc2b4b070c733b36b1971de63977428b
> Compaction loop resulting from small rowset compaction policy (KUDU-1400)
> -------------------------------------------------------------------------
>
> Key: KUDU-2701
> URL: https://issues.apache.org/jira/browse/KUDU-2701
> Project: Kudu
> Issue Type: Bug
> Components: tablet
> Affects Versions: 1.9.0
> Reporter: Will Berkeley
> Assignee: Will Berkeley
> Priority: Blocker
> Fix For: 1.9.0
>
>
> I saw an instance of rowset compaction looping, accomplishing nothing but
> wearing out the disk. The offending compaction's logging is
> {noformat}
> I0213 14:23:51.062127 9268 maintenance_manager.cc:306] P
> 09d6bf7a02124145b43f43cb7a667b3d: Scheduling
> CompactRowSetsOp(39aba63834b441e0b26d7aa5949f92ae): perf score=0.025948
> I0213 14:23:55.630163 8904 maintenance_manager.cc:501] P
> 09d6bf7a02124145b43f43cb7a667b3d:
> CompactRowSetsOp(39aba63834b441e0b26d7aa5949f92ae) complete. Timing: real
> 12.968s user 10.285s sys 0.578s Metrics:
> {"bytes_written":235680573,"cfile_cache_hit":32,"cfile_cache_hit_bytes":44035,"cfile_cache_miss":5750,"cfile_cache_miss_bytes":246197139,"cfile_init":24,"data
> dirs.queue_time_us":162819,"data dirs.run_cpu_time_us":1864,"data
> dirs.run_wall_time_us":1461840,"drs_written":8,"fdatasync":25,"fdatasync_us":1217638,"lbm_read_time_us":79002,"lbm_reads_lt_1ms":5846,"lbm_write_time_us":1043597,"lbm_writes_1-10_ms":2,"lbm_writes_10-100_ms":10,"lbm_writes_gt_100_ms":1,"lbm_writes_lt_1ms":30276,"mutex_wait_us":1,"num_input_rowsets":8,"rows_written":46640210,"spinlock_wait_cycles":1664,"thread_start_us":453,"threads_started":14,"wal-append.queue_time_us":49}
> {noformat}
> The situation is that about 8 16MB rowsets are calculated to compact to 4
> 32MB rowsets, but get written out as 8 16MB rowsets. The trick is that the
> rowsets *aren't* 16MB...they are really 32MB-- 16MB is the size of the base
> data and redos, which is what we use as the "size" for compaction purposes.
> Probably, we should use "everything" ({{Rowset::OnDiskSize()}}) for the
> KUDU-1400 calculations.
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