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Posted to issues@kylin.apache.org by "wangrupeng (Jira)" <ji...@apache.org> on 2020/03/01 01:32:00 UTC

[jira] [Comment Edited] (KYLIN-4341) by-level cuboid intermediate files are left behind and not cleaned up after job is complete

    [ https://issues.apache.org/jira/browse/KYLIN-4341?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17048440#comment-17048440 ] 

wangrupeng edited comment on KYLIN-4341 at 3/1/20 1:31 AM:
-----------------------------------------------------------

Hi, 

Kylin will not delete cuboids file on hdfs when segment building job finished, because if this segment need to be merged, kylin won't calculate again, this will save the calculation resource. If you are sure the segment won't be merged, you can delete the cuboids files on hdfs yourself. :)

So it's not a bug.

 


was (Author: wangrupeng):
Hi, 

Kylin will not delete cuboids file on hdfs when segment building job finished, because if this segment need to be merged, kylin won't calculate again, this will save the calculation resource. If you are sure the segment won't be merged, you can delete the cuboids files on hdfs yourself. :)

 

> by-level cuboid intermediate files are left behind and not cleaned up after job is complete
> -------------------------------------------------------------------------------------------
>
>                 Key: KYLIN-4341
>                 URL: https://issues.apache.org/jira/browse/KYLIN-4341
>             Project: Kylin
>          Issue Type: Bug
>          Components: Job Engine
>    Affects Versions: v2.6.4
>         Environment: Kylin 2.6.4, CenOS 7.6, HDP 2.6.5
>            Reporter: Vsevolod Ostapenko
>            Assignee: wangrupeng
>            Priority: Major
>
> Setup: MR as a cube build engine and by-level cube build strategy (auto picked).
> Upon completion of a cube segment build job a number of intermediate files are still left behind.
> Namely, output of the MR-jobs that produce the base cuboid, subsequent level cuboids, as well as rowkey_stats from the hfile creation step.
> The files in question consume about the same amount of space in HDFS as the final hfile.
> This lead to wasted space in HDFS that is not released for as long as the corresponding cube segment is online. The only point the leaked space is released, is when segment is offlined and cleaned up as part of the segment retention.
> Sample output is as follows.
> {quote}$ hadoop fs -ls -R /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/
> drwxr-xr-x - kylin hdfs 0 2020-01-07 04:44 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89
> drwxr-xr-x - kylin hdfs 0 2020-01-07 04:26 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid
> drwxr-xr-x - kylin hdfs 0 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid
> -rw-r--r-- 2 kylin hdfs 0 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/_SUCCESS
> -rw-r--r-- 2 kylin hdfs 51570048 2020-01-07 04:35 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00000
> -rw-r--r-- 2 kylin hdfs 51477377 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00001
> -rw-r--r-- 2 kylin hdfs 51615162 2020-01-07 04:35 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00002
> -rw-r--r-- 2 kylin hdfs 51591031 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00003
> -rw-r--r-- 2 kylin hdfs 51648914 2020-01-07 04:35 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00004
> -rw-r--r-- 2 kylin hdfs 51532761 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00005
> -rw-r--r-- 2 kylin hdfs 51455652 2020-01-07 04:35 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00006
> -rw-r--r-- 2 kylin hdfs 51552752 2020-01-07 04:36 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_1_cuboid/part-r-00007
> drwxr-xr-x - kylin hdfs 0 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid
> -rw-r--r-- 2 kylin hdfs 0 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid/_SUCCESS
> -rw-r--r-- 2 kylin hdfs 16293012 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid/part-r-00000
> -rw-r--r-- 2 kylin hdfs 16283730 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid/part-r-00001
> -rw-r--r-- 2 kylin hdfs 16288965 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid/part-r-00002
> -rw-r--r-- 2 kylin hdfs 16270572 2020-01-07 04:25 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/cuboid/level_base_cuboid/part-r-00003
> drwxr-xr-x - kylin hdfs 0 2020-01-07 04:23 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/rowkey_stats
> -rw-r--r-- 3 kylin hdfs 155 2020-01-07 04:23 /user/kylin/26x/test_kylin_26x_metadata/kylin-d2cff21e-9f59-6ac8-df34-656a3479433f/vl_aggs_cube_89/rowkey_stats/part-r-00000_hfile
> {quote}
>  
> Removing the job metadata using (metastore.sh clean --jobThreshold Ndays) does not help. Information about the job is removed, but no intermediate files are cleaned up.
> Storage cleanup does not work either (kylin.sh org.apache.kylin.tool.StorageCleanupJob --delete true), because the corresponding segment is still online.
>  
> It looks like cleanup of the intermediate files that generated by MR job as part of the base and level cuboid builds is either not implemented or commented out for whatever reason.



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