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https://issues.apache.org/jira/browse/DRILL-5457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16051081#comment-16051081
]
ASF GitHub Bot commented on DRILL-5457:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/822#discussion_r122312536
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/aggregate/HashAggTemplate.java
---
@@ -512,122 +509,122 @@ private void updateEstMaxBatchSize(RecordBatch
incoming) {
}
}
+ /**
+ * Read and process (i.e., insert into the hash table and aggregate)
records from the current batch.
+ * Once complete, get the incoming NEXT batch and process it as well,
etc.
+ * For 1st phase, may return when an early output needs to be performed.
+ *
+ * @return Agg outcome status
+ */
@Override
public AggOutcome doWork() {
- try {
- // Note: Keeping the outer and inner try blocks here to maintain
some similarity with
- // StreamingAggregate which does somethings conditionally in the
outer try block.
- // In the future HashAggregate may also need to perform some actions
conditionally
- // in the outer try block.
-
- assert ! handlingSpills || currentIndex < Integer.MAX_VALUE;
- outside:
- while (true) {
+ while (true) {
- // This would be called only once - after actual data arrives on
incoming
- if ( schema == null && incoming.getRecordCount() > 0 ) {
- this.schema = incoming.getSchema();
- // Calculate the number of partitions based on actual incoming
data
- delayedSetup();
- }
+ // This would be called only once - first time actual data arrives
on incoming
+ if ( schema == null && incoming.getRecordCount() > 0 ) {
+ this.schema = incoming.getSchema();
+ currentBatchRecordCount = incoming.getRecordCount(); // initialize
for first non empty batch
+ // Calculate the number of partitions based on actual incoming data
+ delayedSetup();
+ }
- // loop through existing records, aggregating the values as
necessary.
- if (EXTRA_DEBUG_1) {
- logger.debug("Starting outer loop of doWork()...");
+ //
+ // loop through existing records in this batch, aggregating the
values as necessary.
+ //
+ if (EXTRA_DEBUG_1) {
+ logger.debug("Starting outer loop of doWork()...");
+ }
+ for (; underlyingIndex < currentBatchRecordCount; incIndex()) {
+ if (EXTRA_DEBUG_2) {
+ logger.debug("Doing loop with values underlying {}, current {}",
underlyingIndex, currentIndex);
}
- for (; underlyingIndex < incoming.getRecordCount(); incIndex()) {
- if (EXTRA_DEBUG_2) {
- logger.debug("Doing loop with values underlying {}, current
{}", underlyingIndex, currentIndex);
- }
- checkGroupAndAggrValues(currentIndex);
- // If adding a group discovered a memory pressure during 1st
phase, then start
- // outputing some partition to free memory.
- if ( earlyOutput ) {
- outputCurrentBatch();
- incIndex(); // next time continue with the next incoming row
- return AggOutcome.RETURN_OUTCOME;
- }
+ checkGroupAndAggrValues(currentIndex);
+ // If adding a group discovered a memory pressure during 1st
phase, then start
+ // outputing some partition downstream in order to free memory.
+ if ( earlyOutput ) {
+ outputCurrentBatch();
+ incIndex(); // next time continue with the next incoming row
+ return AggOutcome.RETURN_OUTCOME;
}
+ }
+
+ if (EXTRA_DEBUG_1) {
+ logger.debug("Processed {} records", underlyingIndex);
+ }
- if (EXTRA_DEBUG_1) {
- logger.debug("Processed {} records", underlyingIndex);
+ // Cleanup the previous batch since we are done processing it.
+ for (VectorWrapper<?> v : incoming) {
--- End diff --
Two comments/questions here.
First, can we be sure that there is always a Selection Vector Remover
between the hash agg and anything that can emit a batch that uses an SV4 (such
as sort)? Otherwise, the `getValueVector()` method won't work.
Second, is it certain that no other code references the vectors from this
container?
If both those invariants are met, then, yes, it is the job of this operator
to release buffers created by the upstream.
> Support Spill to Disk for the Hash Aggregate Operator
> -----------------------------------------------------
>
> Key: DRILL-5457
> URL: https://issues.apache.org/jira/browse/DRILL-5457
> Project: Apache Drill
> Issue Type: Improvement
> Components: Execution - Relational Operators
> Affects Versions: 1.10.0
> Reporter: Boaz Ben-Zvi
> Assignee: Boaz Ben-Zvi
> Fix For: 1.11.0
>
>
> Support gradual spilling memory to disk as the available memory gets too
> small to allow in memory work for the Hash Aggregate Operator.
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