Xianqing He has posted comments on this change. ( http://gerrit.cloudera.org:8080/18711 )
Change subject: IMPALA-11418: A statement that returns at most one row need not to spool results ...................................................................... Patch Set 8: (3 comments) > Patch Set 7: > > > Patch Set 7: > > > > > Patch Set 7: > > > > > > I found another way to optimize this. We can disable result spooling for > > > small queries and modify in > > > https://github.com/apache/impala/blob/f1420ae51b2e00ad093be64a0d2135ca36aa6514/fe/src/main/java/org/apache/impala/planner/Planner.java#L663-L667 > > > Is this way better? > > > > Or use the method SelectStmt#returnsExactlyOneRow, if the query return one > > row disable result spooling. > > If checkForSmallQueryOptimization is on, it implies that query will run in > single backend only. There might be a case later where we can extend this > spool disabling for large query that return only single row only. Checking > SelectStmt#returnsExactlyOneRow is probably a better alternative. The final solution checks SelectStmt#returnsAtMostOneRow http://gerrit.cloudera.org:8080/#/c/18711/4/fe/src/main/java/org/apache/impala/analysis/AnalysisContext.java File fe/src/main/java/org/apache/impala/analysis/AnalysisContext.java: http://gerrit.cloudera.org:8080/#/c/18711/4/fe/src/main/java/org/apache/impala/analysis/AnalysisContext.java@474 PS4, Line 474: A statement that returns at most one row does not need to spool que > nit: A statement that only selects constant does not need to spool query re Done http://gerrit.cloudera.org:8080/#/c/18711/4/fe/src/main/java/org/apache/impala/analysis/AnalysisContext.java@475 PS4, Line 475: > nit: "result spooling is enabled" Done http://gerrit.cloudera.org:8080/#/c/18711/4/fe/src/main/java/org/apache/impala/analysis/AnalysisContext.java@480 PS4, Line 480: + "one row."); > Can you add LOG.trace here? Like what we have in: Done -- To view, visit http://gerrit.cloudera.org:8080/18711 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Icd4d73c21106048df68a270cf03d4abd56bd3aac Gerrit-Change-Number: 18711 Gerrit-PatchSet: 8 Gerrit-Owner: Xianqing He <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: Riza Suminto <[email protected]> Gerrit-Reviewer: Xianqing He <[email protected]> Gerrit-Comment-Date: Fri, 09 Sep 2022 09:18:01 +0000 Gerrit-HasComments: Yes
