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https://issues.apache.org/jira/browse/HIVE-24313?focusedWorklogId=549759&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-549759
]
ASF GitHub Bot logged work on HIVE-24313:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Feb/21 18:27
Start Date: 08/Feb/21 18:27
Worklog Time Spent: 10m
Work Description: okumin commented on a change in pull request #1636:
URL: https://github.com/apache/hive/pull/1636#discussion_r572272405
##########
File path: ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java
##########
@@ -316,12 +319,11 @@ private static Statistics collectStatistics(HiveConf
conf, PrunedPartitionList p
basicStatsFactory.addEnhancer(new
BasicStats.RowNumEstimator(estimateRowSizeFromSchema(conf, schema)));
- List<BasicStats> partStats = new ArrayList<>();
+ List<BasicStats> partStats =
+ partList.getNotDeniedPartns().parallelStream().
Review comment:
The point is `basicStatsFactory.build(Partish.buildFor(table, p))` can
block the common pool shared with a whole JVM since it executes blocking-IO?
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Issue Time Tracking
-------------------
Worklog Id: (was: 549759)
Time Spent: 1.5h (was: 1h 20m)
> Optimise stats collection for file sizes on cloud storage
> ---------------------------------------------------------
>
> Key: HIVE-24313
> URL: https://issues.apache.org/jira/browse/HIVE-24313
> Project: Hive
> Issue Type: Improvement
> Components: HiveServer2
> Reporter: Rajesh Balamohan
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1.5h
> Remaining Estimate: 0h
>
> When stats information is not present (e.g external table), RelOptHiveTable
> computes basic stats at runtime.
> Following is the codepath.
> [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/RelOptHiveTable.java#L598]
> {code:java}
> Statistics stats = StatsUtils.collectStatistics(hiveConf, partitionList,
> hiveTblMetadata, hiveNonPartitionCols,
> nonPartColNamesThatRqrStats, colStatsCached,
> nonPartColNamesThatRqrStats, true);
> {code}
> [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java#L322]
> {code:java}
> for (Partition p : partList.getNotDeniedPartns()) {
> BasicStats basicStats =
> basicStatsFactory.build(Partish.buildFor(table, p));
> partStats.add(basicStats);
> }
> {code}
> [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/stats/BasicStats.java#L205]
>
> {code:java}
> try {
> ds = getFileSizeForPath(path);
> } catch (IOException e) {
> ds = 0L;
> }
> {code}
>
> For a table & query with large number of partitions, this takes long time to
> compute statistics and increases compilation time. It would be good to fix
> it with "ForkJoinPool" (
> partList.getNotDeniedPartns().parallelStream().forEach((p) )
>
>
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