Tim Armstrong has posted comments on this change.

Change subject: IMPALA-3905: Add single-threaded scan node.
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Patch Set 3:

(10 comments)

http://gerrit.cloudera.org:8080/#/c/4113/3/be/src/exec/hdfs-avro-scanner.cc
File be/src/exec/hdfs-avro-scanner.cc:

Line 768: Function* HdfsAvroScanner::CodegenMaterializeTuple(
It looks like you rebased onto an older commit somehow, I'm seeing a lot of 
unrelated changes in the diff.


http://gerrit.cloudera.org:8080/#/c/4113/1/be/src/exec/hdfs-scan-node-base.h
File be/src/exec/hdfs-scan-node-base.h:

Line 69: 
> Not following the first part (space where?).
I was thinking there should be a newline (comment wasn't clear) but it's no 
longer relevant.


http://gerrit.cloudera.org:8080/#/c/4113/3/be/src/exec/hdfs-scan-node-mt.cc
File be/src/exec/hdfs-scan-node-mt.cc:

PS3, Line 48: !files.second.empty() 
Do we have test coverage for this case?


Line 72:   if (scan_range_ == NULL || scanner_->eos()) {
Is the invariant that scan_range_ != NULL implies scanner_ != NULL? I think 
that's true before eos/error has been returned (and callers shouldn't be 
calling GetNext() after eos). Would be good to add a DCHECK to document the 
invariant.


PS3, Line 73: .get()
the .get() isn't necessary (NULL comparisons against scoped_ptr work)


http://gerrit.cloudera.org:8080/#/c/4113/3/be/src/exec/hdfs-scan-node.cc
File be/src/exec/hdfs-scan-node.cc:

Line 196:   SCOPED_TIMER(runtime_profile_->total_time_counter());
I think it would be better to consistently follow the rule that the bottom-most 
class in the hierarchy tracks the timing, rather than having a timer at 
multiple levels of the class hierarchy. We already do this, e.g. 
ExecNode::Open() doesn't have any timers.


http://gerrit.cloudera.org:8080/#/c/4113/1/be/src/exec/hdfs-scanner.h
File be/src/exec/hdfs-scanner.h:

Line 208:   /// Clones of the conjuncts ExprContexts in 
scan_node_->conjuncts_map(). Each scanner
> Commented on lifetime.
Yeah I think this may be the least of the evils at the moment- it doesn't seem 
like there's an easy simplification here.


Line 270: 
> Added a TODO, hope that's ok for now.
Yeah, definitely don't need to fix it now.


http://gerrit.cloudera.org:8080/#/c/4113/3/be/src/exec/hdfs-scanner.h
File be/src/exec/hdfs-scanner.h:

Line 131:   /// TODO: The code at callers could be simplified if eos was 
instead a member
Stale comment?


http://gerrit.cloudera.org:8080/#/c/4113/3/be/src/exec/scanner-context.h
File be/src/exec/scanner-context.h:

PS3, Line 298: ..
extra .


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Gerrit-MessageType: comment
Gerrit-Change-Id: I98cc7f970e1575dd83875609985e1877ada3d5e0
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Alex Behm <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-HasComments: Yes

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