[GitHub] [druid] gianm commented on a change in pull request #11950: Improve on-heap aggregator footprint estimates.

[GitBox <gi...@apache.org>]

gianm commented on a change in pull request #11950:
URL: https://github.com/apache/druid/pull/11950#discussion_r756228094



##########
File path: processing/src/main/java/org/apache/druid/segment/incremental/OnheapIncrementalIndex.java
##########
@@ -114,10 +122,13 @@
   private static long getMaxBytesPerRowForAggregators(IncrementalIndexSchema incrementalIndexSchema)
   {
     long maxAggregatorIntermediateSize = ((long) Integer.BYTES) * incrementalIndexSchema.getMetrics().length;
-    maxAggregatorIntermediateSize += Arrays.stream(incrementalIndexSchema.getMetrics())
-                                           .mapToLong(aggregator -> aggregator.getMaxIntermediateSizeWithNulls()
-                                                                    + Long.BYTES * 2L)
-                                           .sum();
+
+    for (final AggregatorFactory aggregator : incrementalIndexSchema.getMetrics()) {
+      final long rows =
+          incrementalIndexSchema.isRollup() ? ROLLUP_RATIO_FOR_AGGREGATOR_FOOTPRINT_ESTIMATION : 1;
+      maxAggregatorIntermediateSize += (long) aggregator.guessAggregatorHeapFootprint(rows) + 2 * Long.BYTES;

Review comment:
       It's still useful for aggregators that have a small data size, like longSum etc. For those, the overheads are bigger than the intermediate data size.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org