Sailesh Mukil has posted comments on this change.

Change subject: IMPALA-3804: Push per-split filtering into scanners
......................................................................


Patch Set 3:

(7 comments)

http://gerrit.cloudera.org:8080/#/c/3561/3//COMMIT_MSG
Commit Message:

PS3, Line 16: scanner
scanned


http://gerrit.cloudera.org:8080/#/c/3561/3/be/src/exec/hdfs-parquet-scanner.cc
File be/src/exec/hdfs-parquet-scanner.cc:

PS3, Line 127: scan_node->IsZeroSlotTableScan() && footer_split != split
Looks much better now!


PS3, Line 1875: if (ScanRangeIsFilteredOut())
A scan range being filtered out basically translates to "this scan range 
belongs to a partition that should be pruned".

Why do this here rather than in IssueInitialRanges()? We have all the 
information necessary to do it there, i.e. the partition_id and the filter 
contexts.

So we can avoid even scheduling the scan ranges that need to be filtered out. 
Can be done in L133.


PS3, Line 2095: if 
(scan_node_->PartitionIsFilteredOut(context_->partition_descriptor()->id(),
              :             FilterStats::ROW_GROUPS_KEY, 
context_->filter_ctxs())) {
Why do we need to call this again here? Wouldn't the partition have already 
been filtered out in L1875 if it was supposed to?


http://gerrit.cloudera.org:8080/#/c/3561/3/be/src/exec/hdfs-scanner.h
File be/src/exec/hdfs-scanner.h:

PS3, Line 426: enum CloseRangePolicy {
             :     CLOSE_ALL,
             :     CLOSE_ONLY_THIS_RANGE,
             :     CLOSE_NONE
             :   };
Still needed?


http://gerrit.cloudera.org:8080/#/c/3561/3/be/src/exec/hdfs-text-scanner.cc
File be/src/exec/hdfs-text-scanner.cc:

PS3, Line 192: 
Good catch removing this unnecessary condition.


PS3, Line 148: ScanRangeIsFilteredOut
Same here. Why issue a scan range if it could be filtered out in 
IssueInitialRanges()?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I9f92178f642695e0e9ef901373a5e9f2878a78ce
Gerrit-PatchSet: 3
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Henry Robinson <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Henry Robinson <[email protected]>
Gerrit-Reviewer: Sailesh Mukil <[email protected]>
Gerrit-HasComments: Yes

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