[
https://issues.apache.org/jira/browse/HIVE-14423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15410491#comment-15410491
]
Lefty Leverenz commented on HIVE-14423:
---------------------------------------
Doc note: This changes the default value of
*hive.metastore.fshandler.threads*, which was introduced by HIVE-13901 (2.1.1
and 2.2.0) but is not documented in the wiki yet.
Will this also be committed to branch-2.1 for release 2.1.1?
> S3: Fetching partition sizes from FS can be expensive when stats are not
> available in metastore
> ------------------------------------------------------------------------------------------------
>
> Key: HIVE-14423
> URL: https://issues.apache.org/jira/browse/HIVE-14423
> Project: Hive
> Issue Type: Improvement
> Reporter: Rajesh Balamohan
> Assignee: Rajesh Balamohan
> Priority: Minor
> Labels: TODOC2.2
> Fix For: 2.2.0
>
> Attachments: HIVE-14423.1.patch, HIVE-14423.2.patch
>
>
> When partition stats are not available in metastore, it tries to get the file
> sizes from FS.
> e.g
> {noformat}
> at
> org.apache.hadoop.fs.FileSystem.getContentSummary(FileSystem.java:1487)
> at
> org.apache.hadoop.hive.ql.stats.StatsUtils.getFileSizeForPartitions(StatsUtils.java:598)
> at
> org.apache.hadoop.hive.ql.stats.StatsUtils.collectStatistics(StatsUtils.java:235)
> at
> org.apache.hadoop.hive.ql.stats.StatsUtils.collectStatistics(StatsUtils.java:144)
> at
> org.apache.hadoop.hive.ql.stats.StatsUtils.collectStatistics(StatsUtils.java:132)
> at
> org.apache.hadoop.hive.ql.optimizer.stats.annotation.StatsRulesProcFactory$TableScanStatsRule.process(StatsRulesProcFactory.java:126)
> at
> org.apache.hadoop.hive.ql.lib.DefaultRuleDispatcher.dispatch(DefaultRuleDispatcher.java:90)
> at
> org.apache.hadoop.hive.ql.lib.DefaultGraphWalker.dispatchAndReturn(DefaultGraphWalker.java:105)
> {noformat}
> This can be quite expensive in some FS like S3. Especially when table is
> partitioned (e.g TPC-DS store_sales which has 1000s of partitions), query can
> spend 1000s of seconds just waiting for these information to be pulled in.
> Also, it would be good to remove FS.getContentSummary usage to find out file
> sizes.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
