Amos Bird has posted comments on this change. Change subject: IMPALA-1654: DDL for multiple partitions ......................................................................
Patch Set 3: (1 comment) http://gerrit.cloudera.org:8080/#/c/5726/3/docs/topics/impala_alter_table.xml File docs/topics/impala_alter_table.xml: Line 144: For example, you might drop a group of partitions corresponding to a particular date > Does the scalability bottleneck apply when the number of matching partition >Does the scalability bottleneck apply when the number of matching partitions >is high, or just generally when the table has a lot of partitions regardless >of how many match? when there are a lot of matching partitions. >Do we have any guidance to offer (e.g. "don't use this idiom on tables with >tens of thousands of partitions", or "under circumstances XYZ, issue multiple >ALTER TABLE statements, each for one partition")? well it just acts like we are issueing multiple single DROP stmts, so there isn't a guidance. User has to pay such laytency for now if those partitions are needed to be dropped. >Does any issue manifest itself just as a single slow DDL statement, or does >the hms traffic potentially cause other statements to wait, or other symptoms? it's holding a lock of targeting table, so other DDLs related will be blocked. -- To view, visit http://gerrit.cloudera.org:8080/5726 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I2060552d5081e5f93b1b1f398414c52fa03f215b Gerrit-PatchSet: 3 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: John Russell <[email protected]> Gerrit-Reviewer: Alex Behm <[email protected]> Gerrit-Reviewer: Amos Bird <[email protected]> Gerrit-Reviewer: John Russell <[email protected]> Gerrit-HasComments: Yes
