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https://issues.apache.org/jira/browse/HIVE-24367?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Harshit Gupta reassigned HIVE-24367:
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Assignee: Harshit Gupta
> Explore whether HiveAlterHandler::alterTable can be optimised for
> non-partitioned tables
> ----------------------------------------------------------------------------------------
>
> Key: HIVE-24367
> URL: https://issues.apache.org/jira/browse/HIVE-24367
> Project: Hive
> Issue Type: Improvement
> Components: HiveServer2
> Reporter: Rajesh Balamohan
> Assignee: Harshit Gupta
> Priority: Major
>
> {color:#222222}Writing lots of delta in non-partitioned table creates runtime
> issues, when lot of delta folders are present.{color}
> {color:#222222} {color}
> {color:#222222}Following code in HiveAlterHandler is invoked for every insert
> operation. It computes {{{color}
> {color:#222222}updateTableStatsSlow}} for every insert causing runtime
> delays.{color}
> {color:#222222} {color}
> {noformat}
> if (MetaStoreUtils.requireCalStats(null, null, newt, environmentContext) &&
> !isPartitionedTable) {
> Database db = msdb.getDatabase(catName, newDbName);
> assert(isReplicated == HiveMetaStore.HMSHandler.isDbReplicationTarget(db));
> // Update table stats. For partitioned table, we update stats in
> alterPartition()
> MetaStoreUtils.updateTableStatsSlow(db, newt, wh, false, true,
> environmentContext);
> }
> {noformat}
> {color:#222222}It would be good to explore whether only the newly added delta
> can be listed for computing stats. This would avoid huge listing call during
> stats collection.{color}
> {color:#222222}e.g queries to repro{color}
> {noformat}
> CREATE TABLE IF NOT EXISTS test (name String, value int);
> INSERT INTO test VALUES('K1',1);
> INSERT INTO test VALUES('K2',2);
> ..
> ..
> ..
> INSERT INTO test VALUES('K20000',2)
> {noformat}
>
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