drill git commit: DRILL-2835: Fix issue in copying data when a PartitionSender outgoing batch is in dropAll mode

[ve...@apache.org]

Repository: drill
Updated Branches:
  refs/heads/master a0a1930c4 -> fbb405bdb


DRILL-2835: Fix issue in copying data when a PartitionSender outgoing batch is in dropAll mode

"dropAll" mode means
-- the fragment has exhausted all input data or
-- receiver of the outgoing batch has finished (possible in case of LIMIT)


Project: http://git-wip-us.apache.org/repos/asf/drill/repo
Commit: http://git-wip-us.apache.org/repos/asf/drill/commit/fbb405bd
Tree: http://git-wip-us.apache.org/repos/asf/drill/tree/fbb405bd
Diff: http://git-wip-us.apache.org/repos/asf/drill/diff/fbb405bd

Branch: refs/heads/master
Commit: fbb405bdb0b55477d9f73b8eba91a49091e5b6d4
Parents: a0a1930
Author: vkorukanti <ve...@gmail.com>
Authored: Mon Apr 20 18:07:42 2015 -0700
Committer: vkorukanti <ve...@gmail.com>
Committed: Tue Apr 21 11:36:53 2015 -0700

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 .../impl/partitionsender/PartitionerTemplate.java     | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
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http://git-wip-us.apache.org/repos/asf/drill/blob/fbb405bd/exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/partitionsender/PartitionerTemplate.java
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diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/partitionsender/PartitionerTemplate.java b/exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/partitionsender/PartitionerTemplate.java
index 440af59..cbea267 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/partitionsender/PartitionerTemplate.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/partitionsender/PartitionerTemplate.java
@@ -267,14 +267,24 @@ public abstract class PartitionerTemplate implements Partitioner {
 
     public void flush(boolean schemaChanged) throws IOException {
       if (dropAll) {
-        vectorContainer.zeroVectors();
+        // If we are in dropAll mode, we still want to copy the data, because we can't stop copying a single outgoing
+        // batch with out stopping all outgoing batches. Other option is check for status of dropAll before copying
+        // every single record in copy method which has the overhead for every record all the time. Resetting the output
+        // count, reusing the same buffers and copying has overhead only for outgoing batches whose receiver has
+        // terminated.
+
+        // Reset the count to 0 and use existing buffers for exhausting input where receiver of this batch is terminated
+        recordCount = 0;
         return;
       }
       final FragmentHandle handle = context.getHandle();
 
       // We need to send the last batch when
       //   1. we are actually done processing the incoming RecordBatches and no more input available
-      //   2. receiver wants to terminate (possible in case of queries involving limit clause)
+      //   2. receiver wants to terminate (possible in case of queries involving limit clause). Even when receiver wants
+      //      to terminate we need to send at least one batch with "isLastBatch" set to true, so that receiver knows
+      //      sender has acknowledged the terminate request. After sending the last batch, all further batches are
+      //      dropped.
       final boolean isLastBatch = isLast || terminated;
 
       // if the batch is not the last batch and the current recordCount is zero, then no need to send any RecordBatches