Add Exchange before GroupId to improve Partial Aggregation #105
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The idea was abandoned during prestodb/presto#11267 review.
findepi
force-pushed
the
findepi/master/add-exchange-before-groupid-to-improve-partial-aggregation-16b5ea
branch
from
8a9c180
to
ca60479
Compare
kokosing
approved these changes
Jan 30, 2019
| .map(newAggregation -> { | ||
| PlanNode newProject = project.replaceChildren(ImmutableList.of(newAggregation)); | ||
| PlanNode newExchange = exchange.replaceChildren(ImmutableList.of(newProject)); | ||
| return Result.ofPlanNode(newExchange); |
There was a problem hiding this comment.
I would inline these, then structure of the code matches the structure of the plan.
|
|
||
| double aggregationMemoryRequirements = estimateAggregationMemoryRequirements(groupingKeys, groupId, groupingSetHistogram, context); | ||
| if (isNaN(aggregationMemoryRequirements) || aggregationMemoryRequirements < maxPartialAggregationMemoryUsage.toBytes()) { | ||
| // Aggregation will be effective even without exchanges. |
There was a problem hiding this comment.
it is not true when isNaN(aggregationMemoryRequirements)
| * GroupId (before multiplication) makes partial aggregation more effective, resulting in less data being | ||
| * exchanged afterwards. | ||
| */ | ||
| public class AddExchangesBelowPartialAggregationOverGroupIdRuleSet |
There was a problem hiding this comment.
It would be nice to have unit test for that
There was a problem hiding this comment.
That would probably be actually useless -- prestodb/presto#11741 (comment)
sopel39
reviewed
Jan 30, 2019
| @@ -267,6 +268,7 @@ private LocalQueryRunner(Session defaultSession, FeaturesConfig featuresConfig, | |||
| requireNonNull(defaultSession, "defaultSession is null"); | |||
| checkArgument(!defaultSession.getTransactionId().isPresent() || !withInitialTransaction, "Already in transaction"); | |||
|
|
|||
| this.taskManagerConfig = new TaskManagerConfig().setTaskConcurrency(4); | |||
There was a problem hiding this comment.
need what? this only extracts TaskManagerConfig to a variable. I will separate this into preparatory commit
findepi
force-pushed
the
findepi/master/add-exchange-before-groupid-to-improve-partial-aggregation-16b5ea
branch
from
ca60479
to
d7def7d
Compare
The rule brings significant improvement in TPC-DS Q22 and Q67 while not causing much regression in other TPC-H, TPC-DS queries. (The only observably regressing queries were still much better than non-CBO baseline.)
findepi
force-pushed
the
findepi/master/add-exchange-before-groupid-to-improve-partial-aggregation-16b5ea
branch
from
cd5fc64
to
270f8a3
Compare
findepi
deleted the
findepi/master/add-exchange-before-groupid-to-improve-partial-aggregation-16b5ea
branch
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Ref prestodb/presto#11741