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https://issues.apache.org/jira/browse/DRILL-5601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16086503#comment-16086503
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ASF GitHub Bot commented on DRILL-5601:
---------------------------------------
Github user Ben-Zvi commented on a diff in the pull request:
https://github.com/apache/drill/pull/860#discussion_r124435170
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/xsort/managed/SortMemoryManager.java
---
@@ -312,52 +488,66 @@ private void adjustForLowMemory() {
* one spill batch to make progress.
*/
- private void lowMemorySpillBatchSize() {
+ private void lowMemoryInternalBatchSizes() {
// The "expected" size is with power-of-two rounding in some vectors.
// We later work backwards to the row count assuming average internal
// fragmentation.
- // Must hold two input batches. Use (most of) the rest for the spill
batch.
+ // Must hold two input batches. Use half of the rest for the spill
batch.
+ // In a really bad case, the number here may be negative. We'll fix
+ // it below.
- expectedSpillBatchSize = (int) (memoryLimit - 2 * estimatedInputSize);
+ int spillBufferSize = (int) (memoryLimit - 2 *
inputBatchSize.maxBufferSize) / 2;
--- End diff --
(1) spilled "buffer" or spilled "batch" size ?
(2) Where is the possible negative number fixed ? Looks like
setFromWorstCase() would set all three fields to negative numbers.
> Rollup of External Sort memory management fixes
> -----------------------------------------------
>
> Key: DRILL-5601
> URL: https://issues.apache.org/jira/browse/DRILL-5601
> Project: Apache Drill
> Issue Type: Task
> Affects Versions: 1.11.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Fix For: 1.12.0
>
>
> Rollup of a set of specific JIRA entries that all relate to the very
> difficult problem of managing memory within Drill in order for the external
> sort to stay within a memory budget. In general, the fixes relate to better
> estimating memory used by the three ways that Drill allocates vector memory
> (see DRILL-5522) and to predicting the size of vectors that the sort will
> create, to avoid repeated realloc-copy cycles (see DRILL-5594).
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