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https://issues.apache.org/jira/browse/HIVE-25580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17422984#comment-17422984
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David Mollitor commented on HIVE-25580:
---------------------------------------
Sorry, was looking at an older version of the schema. 4.0 is:
{code:sql}
CREATE INDEX TAB_COL_STATS_IDX ON TAB_COL_STATS (CAT_NAME, DB_NAME, TABLE_NAME,
COLUMN_NAME) USING BTREE;
{code}
> Increase the performance of getTableColumnStatistics and
> getPartitionColumnStatistics
> -------------------------------------------------------------------------------------
>
> Key: HIVE-25580
> URL: https://issues.apache.org/jira/browse/HIVE-25580
> Project: Hive
> Issue Type: Improvement
> Components: Standalone Metastore
> Reporter: Peter Vary
> Assignee: Peter Vary
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> When the PART_COL_STATS table contains high number of rows the
> getTableColumnStatistics and getPartitionColumnStatistics response time
> increases.
> The root cause is the full table scan for the jdbc query below:
> {code:java}
> 2021-09-27 13:22:44,218 DEBUG DataNucleus.Datastore.Native:
> [pool-6-thread-199]: SELECT DISTINCT "A0"."ENGINE" FROM "PART_COL_STATS" "A0"
> 2021-09-27 13:22:50,569 DEBUG DataNucleus.Datastore.Retrieve:
> [pool-6-thread-199]: Execution Time = 6351 ms {code}
> The time spent in
> [here|https://github.com/apache/hive/blob/ed1882ef569f8d00317597c269cfae35ace5a5fa/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java#L9965]:
> {code:java}
> query = pm.newQuery(MPartitionColumnStatistics.class);
> query.setResult("DISTINCT engine");
> Collection names = (Collection) query.execute();
> {code}
> We might get a better performance if we limit the query range based on the
> cat/db/table.
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