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https://issues.apache.org/jira/browse/DRILL-6307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16447474#comment-16447474
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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_r183264768
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/record/RecordBatchSizer.java
---
@@ -277,18 +286,29 @@ public boolean isRepeatedList() {
/**
* This is the average per entry width, used for vector allocation.
*/
- public int getEntryWidth() {
+ private int getEntryWidthForAlloc() {
int width = 0;
if (isVariableWidth) {
- width = getNetSizePerEntry() - OFFSET_VECTOR_WIDTH;
+ width = getAllocSizePerEntry() - OFFSET_VECTOR_WIDTH;
// Subtract out the bits (is-set) vector width
- if (metadata.getDataMode() == DataMode.OPTIONAL) {
+ if (isOptional) {
width -= BIT_VECTOR_WIDTH;
}
+
+ if (isRepeated && getValueCount() == 0) {
+ return (safeDivide(width, STD_REPETITION_FACTOR));
+ }
}
- return (safeDivide(width, cardinality));
+ return (safeDivide(width, getEntryCardinalityForAlloc()));
+ }
+
+ /**
+ * This is the average per entry cardinality, used for vector
allocation.
+ */
+ private float getEntryCardinalityForAlloc() {
+ return getCardinality() == 0 ? (isRepeated ? STD_REPETITION_FACTOR :
1) :getCardinality();
--- End diff --
I'm a bit curious: under what scenario do we want to allocate vectors given
no input rows? Can we just wait to see data before we do our allocations? It is
very hard to make reasonable estimates of future size based on no data...
> 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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