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https://issues.apache.org/jira/browse/DRILL-6307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16447472#comment-16447472
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ASF GitHub Bot commented on DRILL-6307:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/1228#discussion_r183264235
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/record/RecordBatchSizer.java
---
@@ -50,7 +50,7 @@
public class RecordBatchSizer {
private static final int OFFSET_VECTOR_WIDTH = UInt4Vector.VALUE_WIDTH;
private static final int BIT_VECTOR_WIDTH = UInt1Vector.VALUE_WIDTH;
- private static final int STD_REPETITION_FACTOR = 10;
+ public static final int STD_REPETITION_FACTOR = 10;
--- End diff --
This is another of those silly fudge factors that really have no meaning.
The value of 10 came from the vector allocation code in `AllocationHelper` (or
I thought it did, the magic number there is 5.)
Maybe move this to `AllocationHelper` and set it to 5, then use it here and
in `AllocationHelper` so we use a consistent guess everywhere.
> Handle empty batches in record batch sizer correctly
> ----------------------------------------------------
>
> Key: DRILL-6307
> URL: https://issues.apache.org/jira/browse/DRILL-6307
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Flow
> Affects Versions: 1.13.0
> Reporter: Padma Penumarthy
> Assignee: Padma Penumarthy
> Priority: Major
> Fix For: 1.14.0
>
>
> when we get empty batch, record batch sizer calculates row width as zero. In
> that case, we do not do accounting and memory allocation correctly for
> outgoing batches.
> For example, in merge join, for outer left join, if right side batch is
> empty, we still have to include the right side columns as null in outgoing
> batch.
> Say first batch is empty. Then, for outgoing, we allocate empty vectors with
> zero capacity. When we read the next batch with data, we will end up going
> through realloc loop. If we use right side row width as 0 in outgoing row
> width calculation, number of rows we will calculate will be higher and later
> when we get a non empty batch, we might exceed the memory limits.
> One possible workaround/solution : Allocate memory based on std size for
> empty input batch. Use allocation width as width of the batch in number of
> rows calculation.
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