Todd Lipcon has posted comments on this change. ( http://gerrit.cloudera.org:8080/12974 )
Change subject: IMPALA-7608: Estimate row count from file size when no stats available ...................................................................... Patch Set 8: (1 comment) http://gerrit.cloudera.org:8080/#/c/12974/8/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java File fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java: http://gerrit.cloudera.org:8080/#/c/12974/8/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java@1198 PS8, Line 1198: // estimated row count by ESTIMATED_COMPRESSION_FACTOR. Should we estimate the compression factor differently depending on the file format? eg text I would guess would have a much lower compression factor than parquet. Might be interesting to look at some emprical data here since changing it later could change plans, and seems not too hard to do a little research -- To view, visit http://gerrit.cloudera.org:8080/12974 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ic414121c8df0d5222e4aeea096b5365beb04568a Gerrit-Change-Number: 12974 Gerrit-PatchSet: 8 Gerrit-Owner: Fang-Yu Rao <fangyu....@cloudera.com> Gerrit-Reviewer: Fang-Yu Rao <fangyu....@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Paul Rogers <prog...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Reviewer: Todd Lipcon <t...@apache.org> Gerrit-Comment-Date: Fri, 17 May 2019 04:44:57 +0000 Gerrit-HasComments: Yes
