Release memory held by aggs on failure (#72966)

If consuming a query result were disrupted by circuit breaker we would
leak memory for aggs in buffered query results, fixed.

Relates #62439 and #72309

Closes #72923

server/src/main/java/org/elasticsearch/action/search/QueryPhaseResultConsumer.java

@@ -311,6 +311,8 @@ public void consume(QuerySearchResult result, Runnable next) {
                             addEstimateAndMaybeBreak(aggsSize);
                         } catch (Exception exc) {
                             result.releaseAggs();
+                            buffer.forEach(QuerySearchResult::releaseAggs);
+                            buffer.clear();
                             onMergeFailure(exc);
                             next.run();
                             return;
@@ -402,17 +404,20 @@ protected void doRun() {
                     final MergeResult thisMergeResult = mergeResult;
                     long estimatedTotalSize = (thisMergeResult != null ? thisMergeResult.estimatedSize : 0) + task.aggsBufferSize;
                     final MergeResult newMerge;
+                    final QuerySearchResult[] toConsume = task.consumeBuffer();
+                    if (toConsume == null) {
+                        return;
+                    }
                     try {
-                        final QuerySearchResult[] toConsume = task.consumeBuffer();
-                        if (toConsume == null) {
-                            return;
-                        }
                         long estimatedMergeSize = estimateRamBytesUsedForReduce(estimatedTotalSize);
                         addEstimateAndMaybeBreak(estimatedMergeSize);
                         estimatedTotalSize += estimatedMergeSize;
                         ++ numReducePhases;
                         newMerge = partialReduce(toConsume, task.emptyResults, topDocsStats, thisMergeResult, numReducePhases);
                     } catch (Exception t) {
+                        for (QuerySearchResult result : toConsume) {
+                            result.releaseAggs();
+                        }
                         onMergeFailure(t);
                         return;
                     }
@@ -507,7 +512,12 @@ public void consumeListener() {
         }
 
         public synchronized void cancel() {
-            consumeBuffer();
+            QuerySearchResult[] buffer = consumeBuffer();
+            if (buffer != null) {
+                for (QuerySearchResult result : buffer) {
+                    result.releaseAggs();
+                }
+            }
             consumeListener();
         }
     }