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https://issues.apache.org/jira/browse/HIVE-22255?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17165533#comment-17165533
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Karen Coppage commented on HIVE-22255:
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[~asetty] The point is that old base directories are cleaned up –– so it only
matters that the cleaner runs. Compaction itself will be skipped. Basically,
with this change
# we queue (major, doesn't really matter) compaction
# the compaction Worker thread picks up the table from the queue, sees that
there is one active base and no deltas, (so compaction will be skipped and) the
table will immediately be placed in "ready for cleaning" status
# Cleaner runs and deletes obsolete bases
> Hive don't trigger Major Compaction automatically if table contains only base
> files
> ------------------------------------------------------------------------------------
>
> Key: HIVE-22255
> URL: https://issues.apache.org/jira/browse/HIVE-22255
> Project: Hive
> Issue Type: Bug
> Components: Hive, Transactions
> Affects Versions: 3.1.2
> Environment: Hive-3.1.1
> Reporter: Rajkumar Singh
> Assignee: Rajkumar Singh
> Priority: Major
> Attachments: HIVE-22255.01.patch, HIVE-22255.02.patch,
> HIVE-22255.patch
>
>
> user may run into the issue if the table consists of all base files but no
> delta, then the following condition will yield false and automatic major
> compaction will be skipped.
> [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/Initiator.java#L313]
>
> Steps to Reproduce:
> # create Acid table
> {code:java}
> // create table myacid(id int);
> {code}
> # Run multiple insert table
> {code:java}
> // insert overwrite table myacid values(1);insert overwrite table myacid
> values(2),(3),(4){code}
> # DFS ls output
> {code:java}
> // dfs -ls -R /warehouse/tablespace/managed/hive/myacid;
> +----------------------------------------------------+
> | DFS Output |
> +----------------------------------------------------+
> | drwxrwx---+ - hive hadoop 0 2019-09-27 16:42
> /warehouse/tablespace/managed/hive/myacid/base_0000001 |
> | -rw-rw----+ 3 hive hadoop 1 2019-09-27 16:42
> /warehouse/tablespace/managed/hive/myacid/base_0000001/_orc_acid_version |
> | -rw-rw----+ 3 hive hadoop 610 2019-09-27 16:42
> /warehouse/tablespace/managed/hive/myacid/base_0000001/bucket_00000 |
> | drwxrwx---+ - hive hadoop 0 2019-09-27 16:43
> /warehouse/tablespace/managed/hive/myacid/base_0000002 |
> | -rw-rw----+ 3 hive hadoop 1 2019-09-27 16:43
> /warehouse/tablespace/managed/hive/myacid/base_0000002/_orc_acid_version |
> | -rw-rw----+ 3 hive hadoop 633 2019-09-27 16:43
> /warehouse/tablespace/managed/hive/myacid/base_0000002/bucket_00000 |
> +----------------------------------------------------+{code}
>
> you will see that Major compaction will not be trigger until you run alter
> table compact MAJOR.
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