Use streaming aggregation for a correlated scalar subquery #10731

mbasmanova · 2018-05-31T05:40:56Z

Optimize aggregation in a correlated scalar subquery to remove unnecessary local exchange and partial aggregation and enable streaming mode.

Correlated subquery like

select name, (select max(name) from region where regionkey = nation.regionkey) from nation;

is rewritten to a left join with an aggregation over synthetic row ID column generated by AssignUniqueId node:

- Aggregation (unique, probe.*)
  - LeftJoin
     - AssignUniqueId (unique)
        - probe
     - build

Since "unique" column is unique, the aggregation input is partitioned on grouping keys and therefore aggregation can be executed in a single step without any exchanges. Furthermore, since the output of the join is grouped on "unique" column, the aggregation doesn't need to accumulate all of the input in memory before emitting results. It can generate results every time the value of the "unique" column changes.

This PR implements streaming support in HashAggregationOperator, updates StreamPropertyDerivations and PropertyDerivations to set paritioned_on(unique) and grouped(unique) properties for the output of the AssignUniqueId node, and uses these properties in AddLocalExchanges to enable streaming aggregation.

Fixes #8171

sopel39 · 2018-06-04T10:23:58Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

@@ -45,6 +45,7 @@
    private final PlanNode source;
    private final Map<Symbol, Aggregation> aggregations;
    private final List<List<Symbol>> groupingSets;
+    private final List<Symbol> preGroupedSymbols;


I like that. This is clever and more generic. I was just thinking about another type of aggregation AggregationNode.Step, e.g: STREAMING

Is this like a trait but inside a plan node?

Yes, sort of. It's the same approach we took for WindowNode (prePartitionedInputs, preSortedOrderPrefix)

sopel39 · 2018-06-04T10:26:10Z

presto-main/src/main/java/com/facebook/presto/operator/HashAggregationOperator.java

@@ -295,6 +311,20 @@ public HashAggregationOperator(
        this.groupByTypes = ImmutableList.copyOf(groupByTypes);
        this.groupByChannels = ImmutableList.copyOf(groupByChannels);
        this.globalAggregationGroupIds = ImmutableList.copyOf(globalAggregationGroupIds);
+        this.preGroupedChannels = ImmutableList.copyOf(preGroupedChannels);
+        ImmutableList.Builder<Type> builder = ImmutableList.builder();
+        for (Integer channel : preGroupedChannels) {


extract to a static method

sopel39 · 2018-06-04T10:26:49Z

presto-main/src/main/java/com/facebook/presto/operator/HashAggregationOperator.java

+        this.preGroupedChannels = ImmutableList.copyOf(preGroupedChannels);
+        ImmutableList.Builder<Type> builder = ImmutableList.builder();
+        for (Integer channel : preGroupedChannels) {
+            boolean found = false;


found is unused

sopel39 · 2018-06-04T11:02:14Z

presto-main/src/main/java/com/facebook/presto/operator/HashAggregationOperator.java

@@ -455,7 +528,7 @@ public Page getOutput()
            }

            // only flush if we are finishing or the aggregation builder is full
-            if (!finishing && (aggregationBuilder == null || !aggregationBuilder.isFull())) {
+            if (!finishing && (aggregationBuilder == null || !aggregationBuilder.isFull()) && pendingInput == null) {


This will work poorly if there is a lot of small groups (e.g: we will flush small pages and constantly resetAggregationBuilder).

Additional condition here should be that aggregationBuilder accumulated enough groups.

@findepi @sopel39 Karol, I was wondering about this and was thinking of using MergingPageOutput to avoid producing tiny pages. Do you think that will help?

Probably not as you would allocate aggregation builders per group. It is probably quite expensive as those are complicated objects

sopel39 · 2018-06-04T11:02:44Z

presto-main/src/main/java/com/facebook/presto/operator/HashAggregationOperator.java

+                unfinishedWork = aggregationBuilder.processPage(page.getRegion(0, groupEnd));
+                pendingInput = page.getRegion(groupEnd, page.getPositionCount() - groupEnd);
+            }
+            else {


if groups always span entire page, then you will never flush aggregates

@sopel39 Good catch. Thank you, Karol.

sopel39 · 2018-06-04T11:05:27Z

presto-main/src/main/java/com/facebook/presto/operator/HashAggregationOperator.java

@@ -56,6 +59,7 @@
        private final List<Type> groupByTypes;
        private final List<Integer> groupByChannels;
        private final List<Integer> globalAggregationGroupIds;
+        private final List<Integer> preGroupedChannels;


this is clever but it makes me wonder if we will use this feature of HashAggregationOperator?

I was rather thinking of a dedicated streaming aggregation operator that would allow us to avoid hash lookups, hash computations and so on (e.g: similar as AggregationOperator). Such dedicated streaming aggregation operator should be more performant in correlated subqueries context than extended HashAggregationOperator

@sopel39 @martint Karol, I'm seeing that we currently use AggregationOperator for global aggregations (set of grouping keys is empty) and HashAggregationOperator for all other aggregations. I'm also seeing that correlated subqueries generate aggregations with grouping keys made of unique and all the probe columns. Such aggregations prevent pruning of probe columns and require unnecessary hashing. Alternatively, sub-queries could be using aggregations on just the unique and apply arbitrary grouping function to the probe columns. E.g.

select name, (select max(name) from region where regionkey = nation.regionkey) from nation;

could be re-written to

- Aggregation [unique] -> arbitrary(nation.name), max(region.name) - LeftJoin (region.regionkey = nation.regionkey) - AssignUniqueId - TableScan(nation) - TableScan(region)

This way, the planner would see that aggregation input is grouped on all grouping columns and hashing is unnecessary and be able to plan streaming aggregation without hashing. Otherwise, if the planner only sees that aggregation input is grouped on a subset of grouping columns, it can't automatically decide whether simple aggregation or hash aggregation is better. What do you think?

Alternatively, sub-queries could be using aggregations on just the unique and apply arbitrary grouping function to the probe columns. E.g.

I think such construct will confuse stats computation. We could improve TransformCorrelatedScalarAggregationToJoin though to not include unused symbols in top aggregation. I think for that we would need to extend LateralJoinNode to include explicit list of outputSymbols as JoinNode do.

Nota that pruning passes through LateralJoinNode but correlated (but unused later on) symbols won't be pruned from probe side and will take part in aggregation.

This way, the planner would see that aggregation input is grouped on all grouping columns and hashing is unnecessary and be able to plan streaming aggregation without hashing

I'm confused. I think AssignUniqueId makes all columns grouped (not only uniqueId column). See: https://github.com/prestodb/presto/pull/10731/files/1b9e5c11be55febd887fc80bd1a6fbc68d08da26#diff-64cfd4c0cfe165b7dcc4934f126200e5

sopel39 · 2018-06-04T11:07:41Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

                                Optional.empty()),
                        child.getProperties());
                return rebaseAndDeriveProperties(node, ImmutableList.of(exchange));
            }

-            return planAndEnforceChildren(node, requiredProperties, requiredProperties);
+            StreamPreferredProperties childRequirements = parentPreferences


please move this to a separate rule, similar rule (computes local stream properties): https://github.com/starburstdata/presto/blob/3ec61ddcba8ece1cca5497799b5ec3b46e1177f2/presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddAdaptiveExchangeBelowPartialAggregation.java

@sopel39 @martint Karol, as I was planning these changes I asked Martin if this should be a separate rule. At the time Martin suggested to keep it in AddLocalExchanges (similar to logic in visitWindow) to avoid traversing the tree and re-computing the properties.

That way it makes it harder to migrate AddLocalExchanges to IterativeOptimizer. Maybe we should push harder towards traits.

@kokosing Grzegorz, what do you refer to by traits? Is there an example I could check out?

Traits is a concept of properties but in the world of IterativeOptimizer or Memo (similar to stats or cost), where you store some information (property) about group reference (relation) in the memo. That way you don't need to recompute it per each rule invocation and also you could possibly use it rule pattern saying something like "this rule will trigger when node is aggregation and its source is already pre aggregated by columns a,b,c).

There is some initial (POC) PR about this: #9691, but it requires changes to match the CBO.

sopel39 · 2018-06-05T09:03:50Z

...to-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PropertyDerivations.java

+
+            ImmutableList.Builder<LocalProperty<Symbol>> localPropertiesBuilder = ImmutableList.builder();
+            localPropertiesBuilder.addAll(properties.getLocalProperties());
+            localPropertiesBuilder.add(new GroupingProperty<>(ImmutableSet.of(node.getIdColumn())));


I think we can make stronger statement here that we are grouped on all columns, no?

@sopel39 Karol, I think you are correct. Thanks for pointing it out. It might be the final piece I was missing.

We can say that the data is grouped on {unique + subset-of-source-symbols} for all subsets of the source symbols. This property will survive the join and will allow streaming aggregation without any hashing (as you suggested earlier). I'll implement StreamingAggregationOperator similar to AggregationOperator and drop changes to HashAggregationOperator.

mbasmanova · 2018-06-06T04:04:23Z

@sopel39 Karol, I implemented a dedicated StreamingAggregationOperator similar to AggregationOperator and dropped changes to HashAggregationOperator. Would you take another look?

sopel39 · 2018-06-06T09:31:21Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+    {
+        ImmutableList.Builder<Aggregator> builder = ImmutableList.builder();
+        for (AccumulatorFactory factory : accumulatorFactories) {
+            builder.add(new Aggregator(factory, step));


Do we want to support partial streaming aggregations now?

@sopel39 I don't have a use case for partial streaming aggregation yet and I'm not sure how I would implement it given the concerns you raised on the changes to HashAggregationOperator. E.g. we'd need a reusable/resettable HashAggregationBuilder , right? What are your thoughts?

@sopel39 Karol, I might have misunderstood your question. You are asking about Step#PARTIAL, right? I was thinking about the case when data stream is grouped on a subset of grouping keys.

StreamingAggregationOperator should work for Step#PARTIAL aggregations just fine. Is there anything special that needs to be taken care of?

@mbasmanova I was just wondering if we plan to support partial streaming aggregation at this moment. Both partial streaming aggregation and streaming hash aggregation seem like a great features, but I wonder if there are practical use cases for them at this point.

Do we want to support partial streaming aggregations now?

It occurred to me that such imprecise sentence might be understood with negative bias which I did not intend.

sopel39 · 2018-06-06T09:36:01Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+    private List<Aggregator> aggregates;
+    private final PageBuilder pageBuilder;
+    private Page pendingInput;
+    private Page previousPage;


Maybe instead of whole page we should just store single row from group (seems easier to grasp)

@sopel39 Is where an easy way to do that?

I think similar to what you do but just get region of size 1

@sopel39 Isn't this what previousPage = page.getRegion(page.getPositionCount() - 1, 1); does already?

Yup. I would just change field name then

sopel39 · 2018-06-06T09:36:57Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+
+    private void updateMemoryUsage()
+    {
+        long memorySize = pageBuilder.getRetainedSizeInBytes();


you should account form previous page too

sopel39 · 2018-06-06T09:36:59Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        requireNonNull(page, "page is null");
+
+        if (previousPage != null) {
+            if (!rowEqualsRow(0, previousPage, 0, page)) {


there is implicit assumption that the previous page contains only rows from single group. Maybe consider keeping just a single row from group (my other comment)

sopel39 · 2018-06-06T09:46:58Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        }
+    }
+
+    private void processInput(Page page)


this seems rather complex flow. What would you about something like (pseudo code):

for (row in page) { if (previousGroupRow != null && !previousGroupRow.equals(row)) evaluateAggregatesToPageBuilder(); resetAggregators(); previousGroupRow = null; } addRowToAggregates(); if (previousGroupRow == null) { // first row from group previousGroupRow = row } }

and

void evaluateAggregatesToPageBuilder() { if (pageBuilder.isFull()) { outputPages.add(pageBuiler.build()); pageBuilder.reset(); } ... }

The idea is to store produced output pages in order to simplify processing of input pages.

You wouldn't then have to check
if (pageBuilder.getPositionCount() >= minOutputPageRowCount || pageBuilder.getRetainedSizeInBytes() >= minOutputPageSize.toBytes()) {

because you could write needsInput as:

boolean needsInput() { return !finishing && outputPages.isEmpty() }

In this snipped I used row by row iteration, but that is not how Accumulator work. We should operate on ranges, but principals stay the same.

@sopel39 Karol, thanks for the suggestion. I used some of the ideas to simplify the logic, but couldn't get it to quite the shape you asked for. Any chance you could take another look?

I think the logic in this class (and this method in particular) would be easier to follow if instead of tracking "previousRow" you just kept track of "currentGroup" -- you only need to compare against that, ever.

Then, this method might be rewritten as follows (beware, I haven't tested it or made sure the logic is 100% correct):

private void processInput(Page page) { requireNonNull(page, "page is null"); if (currentGroup != null) { if (!rowEqualsRow(0, page, 0, currentGroup)) { // page starts with new group, so flush it evaluateAggregatesToPageBuilder(currentGroup, 0); currentGroup = page.getRegion(0, 1); if (pageBuilder.isFull()) { return; } } } int startPosition = 0; while (startPosition < page.getPositionCount()) { // may be equal to page.getPositionCount() if the end is not found in this page int nextGroupStart = findNextGroupStart(startPosition, page); addRowsToAggregates(page, startPosition, nextGroupStart - 1); if (nextGroupStart < page.getPositionCount()) { // current group stops somewhere in the middle of the page, so flush it evaluateAggregatesToPageBuilder(page, startPosition); currentGroup = page.getRegion(nextGroupStart, 1); if (pageBuilder.isFull()) { pendingInput = page.getRegion(nextGroupStart, page.getPositionCount() - nextGroupStart + 1); return; } } startPosition = nextGroupStart; } }

with findNextGroupStart as:

private int findNextGroupStart(int startPosition, Page page) { for (int i = startPosition; i < page.getPositionCount(); i++) { if (!rowEqualsRow(i, page, 0, currentGroup)) { return i; } } return page.getPositionCount(); }

sopel39 · 2018-06-06T10:04:26Z

presto-main/src/main/java/com/facebook/presto/sql/planner/LocalExecutionPlanner.java

@@ -2339,6 +2340,10 @@ private PhysicalOperation planGroupByAggregation(
                }
            }

+            boolean streaming = !node.getPreGroupedSymbols().isEmpty()
+                    && node.getGroupingSets().size() == 1
+                    && node.getPreGroupedSymbols().equals(Iterables.getOnlyElement(node.getGroupingSets()));


You probably should compare sets here instead of lists.

sopel39 · 2018-06-06T10:06:11Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

+        private boolean canSkipHashGeneration(AggregationNode node)
+        {
+            if (!node.getPreGroupedSymbols().isEmpty() &&
+                    node.getGroupingSets().size() == 1


add AggregationNode#isStreamingAggregation method. Use it in local execution planner too

sopel39 · 2018-06-06T10:08:11Z

...n/java/com/facebook/presto/sql/planner/iterative/rule/PushPartialAggregationThroughJoin.java

@@ -156,6 +156,7 @@ private AggregationNode replaceAggregationSource(
                source,
                aggregation.getAggregations(),
                ImmutableList.of(groupingSet),
+                ImmutableList.of(),


you shouldn't create non-streaming partial aggregation from streaming aggregation. This will hurt performance and might be incorrect too (partial aggregations might break grouping since they can flush in a an undeterministic way, e.g: mid-group).

sopel39 · 2018-06-06T10:08:18Z

...va/com/facebook/presto/sql/planner/iterative/rule/PushPartialAggregationThroughExchange.java

@@ -215,6 +215,7 @@ private PlanNode split(AggregationNode node, Context context)
                node.getSource(),
                intermediateAggregation,
                node.getGroupingSets(),
+                ImmutableList.of(),


you shouldn't create non-streaming partial aggregation for streaming aggregation. This will hurt performance and might be incorrect too (partial aggregations might break grouping since they can flush in a an undeterministic way).

sopel39 · 2018-06-06T10:10:14Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

+        {
+            if (!node.getPreGroupedSymbols().isEmpty() &&
+                    node.getGroupingSets().size() == 1
+                    && node.getPreGroupedSymbols().equals(Iterables.getOnlyElement(node.getGroupingSets()))) {


You should also check that the only grouping set is non-empty.

sopel39 · 2018-06-07T09:45:43Z

Optional: You could capture pattern:

aggregation
   - left join
      - assign unique id

and then rewrite aggregation to:

aggregation[STREAMING](keys=allProbeSymbols, preGroupedKeys=unique)

this way we would reduce row comparison overhead

sopel39

is this ready for final pass?

sopel39 · 2018-06-07T09:50:59Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

+                // (1) result.getHashSymbols() contains all requiredHashes;
+                // (2) result.getHashSymbols() is a superset of requiredHashes combined with preferredHashes (no pruning is needed)
+                Set<HashComputation> resultHashes = result.getHashSymbols().keySet();
+                preferenceSatisfied = resultHashes.containsAll(requiredHashes.getHashes())


what was the issue here?

@sopel39

For plans where Join and RemoteExchange are separated by AssignUniqueId, this logic prevented the hash on join keys produced by RemoteExchange to be reused by the Join.

This plan (created by the new PushUpAssignUniqueIdThroughRemoteExchange rule)

- Join - AssignUniqueId - RemoteExchange

was changed to

- Join - Project: (add hash on probe join key) - AssignUniqueId - Project: (drop hash on probe join key) - RemoteExchange

E.g.

This query

SELECT name, (SELECT max(name) FROM region WHERE regionkey = nation.regionkey AND length(name) > length(nation.name)) FROM nation

was planned as

- Aggregate[<name, regionkey, unique>] => [name:varchar(25), regionkey:bigint, unique:bigint, max:varchar(25)] max := "max"("name_1") - LeftJoin[("regionkey" = "regionkey_0") AND ("length"("name_1") > "length"("name"))][$hashvalue_17, $hashvalue_18] => [name:varchar(25), regionkey:bigint, unique:bigint, name_1:varchar(25)] Distribution: PARTITIONED - Project[] => [name:varchar(25), regionkey:bigint, unique:bigint, $hashvalue_17:bigint] $hashvalue_17 := "combine_hash"(bigint '0', COALESCE("$operator$hash_code"("regionkey"), 0)) - AssignUniqueId => [name:varchar(25), regionkey:bigint, unique:bigint] - Project[] => [name:varchar(25), regionkey:bigint] - RemoteExchange[REPARTITION][$hashvalue] => name:varchar(25), regionkey:bigint, $hashvalue:bigint - ScanProject[table = local:tpch:nation:sf0.01, originalConstraint = true] => [name:varchar(25), regionkey:bigint, $hashvalue_16:bigint]

instead of

- Aggregate[<name, regionkey, unique>] => [name:varchar(25), regionkey:bigint, unique:bigint, max:varchar(25)] max := "max"("name_1") - LeftJoin[("regionkey" = "regionkey_0") AND ("length"("name_1") > "length"("name"))][$hashvalue, $hashvalue_17] => [name:varchar(25), regionkey:bigint, unique:bigint, name_1:varchar(25)] Distribution: PARTITIONED - AssignUniqueId => [name:varchar(25), regionkey:bigint, $hashvalue:bigint, unique:bigint] - RemoteExchange[REPARTITION][$hashvalue] => name:varchar(25), regionkey:bigint, $hashvalue:bigint - ScanProject[table = local:tpch:nation:sf0.01, originalConstraint = true] => [name:varchar(25), regionkey:bigint, $hashvalue_16:bigint]

sopel39 · 2018-06-07T09:52:28Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

+                // (2) result.getHashSymbols() is a superset of requiredHashes combined with preferredHashes (no pruning is needed)
+                Set<HashComputation> resultHashes = result.getHashSymbols().keySet();
+                preferenceSatisfied = resultHashes.containsAll(requiredHashes.getHashes())
+                    && ImmutableSet.builder()


extract union set to a separate variable

mbasmanova · 2018-06-07T18:56:31Z

@sopel39

is this ready for final pass?

Yes, I think so.

kokosing

Nice!

kokosing · 2018-06-08T05:49:18Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

@@ -45,6 +45,7 @@
    private final PlanNode source;
    private final Map<Symbol, Aggregation> aggregations;
    private final List<List<Symbol>> groupingSets;
+    private final List<Symbol> preGroupedSymbols;


Is this like a trait but inside a plan node?

kokosing · 2018-06-08T05:50:26Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

@@ -185,7 +198,7 @@ public boolean hasOrderings()
    @Override
    public PlanNode replaceChildren(List<PlanNode> newChildren)
    {
-        return new AggregationNode(getId(), Iterables.getOnlyElement(newChildren), aggregations, groupingSets, step, hashSymbol, groupIdSymbol);
+        return new AggregationNode(getId(), Iterables.getOnlyElement(newChildren), aggregations, groupingSets, preGroupedSymbols, step, hashSymbol, groupIdSymbol);


[just thinking] If understand it correctly, then it is hard to say if newChildren is still grouped on preGroupedSymbols

Rule should take care not to produce invalid plan.

Maybe we should validate aggregations at the end of planning like we validate default aggregations with: com.facebook.presto.sql.planner.sanity.ValidateAggregationsWithDefaultValues?

kokosing · 2018-06-08T05:53:29Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

@@ -222,6 +235,16 @@ public boolean hasSingleNodeExecutionPreference(FunctionRegistry functionRegistr
        return (hasEmptyGroupingSet() && !hasNonEmptyGroupingSet()) || (hasDefaultOutput() && !isDecomposable(functionRegistry));
    }

+    public boolean isStreamable()
+    {
+        if (!preGroupedSymbols.isEmpty() && groupingSets.size() == 1) {


don't you need to check that aggregations.isEmpty()?

@kokosing I might be missing something, but aggregations provide the computation to perform on each group (sum, count, arbitrary). We don't want these to be empty.

Sure, I misunderstood what streamable aggregations mean. Thanks.

kokosing · 2018-06-08T06:10:53Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

                                Optional.empty()),
                        child.getProperties());
                return rebaseAndDeriveProperties(node, ImmutableList.of(exchange));
            }

-            return planAndEnforceChildren(node, requiredProperties, requiredProperties);
+            StreamPreferredProperties childRequirements = parentPreferences


That way it makes it harder to migrate AddLocalExchanges to IterativeOptimizer. Maybe we should push harder towards traits.

kokosing · 2018-06-08T06:16:46Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

+            PlanWithProperties child = planAndEnforce(node.getSource(), childRequirements, childRequirements);
+
+            List<Symbol> preGroupedSymbols;
+            if (!groupingKeys.isEmpty()) {


groupingKeys is an union of all symbols in groupingSets. As I understand currently there is no point to find plan with preGroupedSymbols matching groupingKeys if there are multiple entries in groupingSets. Maybe you should collect this only when groupingSets.size() == 1?

kokosing · 2018-06-08T06:21:05Z

presto-main/src/test/java/com/facebook/presto/sql/planner/TestLogicalPlanner.java

+    @Test
+    public void testStreamingAggregationForCorrelatedSubquery()
+    {
+        assertPlanWithSession("SELECT name, (SELECT max(name) FROM region WHERE regionkey = nation.regionkey AND length(name) > length(nation.name)) FROM nation",


please put each argument in separate line like:

method( arg1, arg2, ..., lastArg);

@kokosing I believe I'm doing this except in cases where it consumes too much vertical space without adding any value. I think this is consistent with the rest of the code in this file. Is there a specific change you'd like me to make? Could you point it out?

kokosing · 2018-06-08T06:26:58Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

@@ -670,7 +670,16 @@ private PlanWithProperties planAndEnforce(

            boolean preferenceSatisfied;
            if (pruneExtraHashSymbols) {
-                preferenceSatisfied = result.getHashSymbols().keySet().equals(requiredHashes.getHashes());
+                // Make sure that


shouldn't be this separated to different commit? Can you add a test for that?

@kokosing @sopel39 I don't see any unit tests for HashGenerationOptimizer and I cannot use BaseRuleTest as it is an old-style rule. What should I do? Is there an example I could follow?

kokosing · 2018-06-08T06:27:26Z

...ain/src/main/java/com/facebook/presto/sql/planner/optimizations/HashGenerationOptimizer.java

+                // (1) result has all required hashes
+                // (2) any extra hashes are preferred hashes (e.g. no pruning is needed)
+                Set<HashComputation> resultHashes = result.getHashSymbols().keySet();
+                ImmutableSet<HashComputation> requiredAndPreferredHashes = ImmutableSet.<HashComputation>builder()


declare it as Set

sopel39

reviewed up to: Optimize aggregation in a correlated scalar subquery

sopel39 · 2018-06-11T06:01:38Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

@@ -185,7 +198,7 @@ public boolean hasOrderings()
    @Override
    public PlanNode replaceChildren(List<PlanNode> newChildren)
    {
-        return new AggregationNode(getId(), Iterables.getOnlyElement(newChildren), aggregations, groupingSets, step, hashSymbol, groupIdSymbol);
+        return new AggregationNode(getId(), Iterables.getOnlyElement(newChildren), aggregations, groupingSets, preGroupedSymbols, step, hashSymbol, groupIdSymbol);


Rule should take care not to produce invalid plan.

Maybe we should validate aggregations at the end of planning like we validate default aggregations with: com.facebook.presto.sql.planner.sanity.ValidateAggregationsWithDefaultValues?

sopel39 · 2018-06-11T06:04:31Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

+    {
+        if (!preGroupedSymbols.isEmpty() && groupingSets.size() == 1) {
+            List<Symbol> groupingSet = Iterables.getOnlyElement(groupingSets);
+            return !groupingSet.isEmpty() && Sets.newHashSet(preGroupedSymbols).equals(Sets.newHashSet(groupingSet));


You don't need to check !groupingSet.isEmpty() (is is already implied by !preGroupedSymbols.isEmpty()).

Maybe use ImmutableSet.copyOf instead of Sets.newHashSet

@sopel39 I'm moving these checks to AddLocalExchange and adding a sanity check to the AggregationNode constructor. This should address this comment and Rule should take care not to produce invalid plan above.

Validator makes sure that other rules didn't break input properties of streaming aggregation.

sopel39 · 2018-06-11T06:05:32Z

presto-main/src/main/java/com/facebook/presto/sql/planner/plan/AggregationNode.java

+    {
+        if (!preGroupedSymbols.isEmpty() && groupingSets.size() == 1) {
+            List<Symbol> groupingSet = Iterables.getOnlyElement(groupingSets);
+            return !groupingSet.isEmpty() && Sets.newHashSet(preGroupedSymbols).equals(Sets.newHashSet(groupingSet));


note: aggregation is also streamable when groupingSet contains preGroupedSymbols (but not equals), but we just don't support it yet (via HashAggregationOperator).

@sopel39 That's right

sopel39 · 2018-06-11T06:19:45Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

+            if (!groupingKeys.isEmpty()) {
+                List<LocalProperty<Symbol>> desiredProperties = ImmutableList.of(new GroupingProperty<>(groupingKeys));
+                Iterator<Optional<LocalProperty<Symbol>>> matchIterator = LocalProperties.match(child.getProperties().getLocalProperties(), desiredProperties).iterator();
+                Optional<LocalProperty<Symbol>> groupingRequirement = matchIterator.next();


use getOnlyElement

sopel39 · 2018-06-11T06:20:43Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

+
+            List<Symbol> preGroupedSymbols;
+            if (!groupingKeys.isEmpty()) {
+                List<LocalProperty<Symbol>> desiredProperties = ImmutableList.of(new GroupingProperty<>(groupingKeys));


extract this logic to a separate method

sopel39 · 2018-06-11T06:56:41Z

...n/src/main/java/com/facebook/presto/sql/planner/optimizations/StreamPropertyDerivations.java

                    return leftProperties
-                            .withUnspecifiedPartitioning()


optional: I would extract it to separate commit and maybe add a test

@sopel39 Before I spend too much time building out testing infrastructure, could you tell if there is an existing test I could use as an example. I don't see any unit tests for StreamPropertyDerivations.

When I improved assign unique id node properties I added test like: TestLogicalPlanner#testUsesDistributedJoinIfNaturallyPartitionedOnProbeSymbols (I've synthesized a query for which improvements made a difference).

If it is not possible to find such query for your changes maybe they are unused? We could also skip the test for now if it's really hard to find proper test case.

@sopel39 In isolation, StreamPropertyDerivations changes for LEFT join are not needed. However, they are necessary to propagate newly generated properties of AssignUniqueId. Without LEFT join changes, newly added test TestLogicalPlanner#testStreamingAggregationForCorrelatedSubquery fails.

I can move these changes into a separate commit, but I don't know how to test them without testing changes to AssignUniqueId as well.

sopel39 · 2018-06-11T06:59:19Z

...n/src/main/java/com/facebook/presto/sql/planner/optimizations/StreamPropertyDerivations.java

@@ -431,7 +429,14 @@ public StreamProperties visitEnforceSingleRow(EnforceSingleRowNode node, List<St
        @Override
        public StreamProperties visitAssignUniqueId(AssignUniqueId node, List<StreamProperties> inputProperties)
        {
-            return Iterables.getOnlyElement(inputProperties);
+            StreamProperties properties = Iterables.getOnlyElement(inputProperties);
+            if (properties.getPartitioningColumns().isPresent()) {


add a comment, e.g:

// preserve input (possibly preferred) partitioning

sopel39 · 2018-06-11T07:50:11Z

presto-main/src/test/java/com/facebook/presto/sql/query/TestSubqueries.java

-                                                                                        node(ValuesNode.class)))
-                                                                                .withAlias("NON_NULL", expression("true"))))))))),
-                plan -> assertEquals(countFinalAggregationNodes(plan), extraAggregation ? 2 : 1));
+                        aggregation(ImmutableMap.of("COUNT", functionCall("count", ImmutableList.of("NON_NULL"))),


optional: we could explicitly test aggregation step here.

sopel39 · 2018-06-11T07:51:31Z

presto-main/src/test/java/com/facebook/presto/sql/planner/TestLogicalPlanner.java

+                                                        anyTree(tableScan("nation", ImmutableMap.of("n_name", "name", "n_regionkey", "regionkey"))))),
+                                        anyTree(tableScan("region", ImmutableMap.of("r_name", "name")))))));
+
+        assertPlanWithSession("SELECT name, (SELECT max(name) FROM region WHERE regionkey > nation.regionkey) FROM nation",


add a comment what is the difference from previous test

sopel39 · 2018-06-11T07:52:08Z

presto-main/src/test/java/com/facebook/presto/sql/planner/TestLogicalPlanner.java

+                this.getQueryRunner().getDefaultSession(),
+                false,
+                anyTree(
+                        aggregation(ImmutableList.of(ImmutableList.of("n_name", "n_regionkey", "unique")),


please break lines after each argument.

mbasmanova · 2018-06-14T23:56:31Z

@martint @sopel39 Martin, Karol, thank you for reviews. I addressed your comments and updated the PR.

martint · 2018-06-15T17:19:44Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

@@ -613,6 +633,20 @@ private PlanWithProperties deriveProperties(PlanNode result, List<StreamProperti
        }
    }

+    private List<Symbol> computePreGroupedSymbols(List<List<Symbol>> groupingSets, List<Symbol> groupingKeys, PlanWithProperties childWithProperties)


The name of this method is misleading. It doesn't really compute pre-grouped columns. Rather, it validates that the provided list is pre-grouped (it's an all-or-nothing).

I suspect this is so that we can extend it in the future to return a subset, but it makes reasoning about the code harder. My preference would be to replace it with an implementation that is more precise about the current intent. In fact, you can probably just replace this whole thing with this in the caller:

List<Symbol> preGroupedSymbols = ImmutableList.of(); if (LocalProperties.match(childWithProperties.getProperties().getLocalProperties(), new GroupingProperty<>(groupingKeys)).isPresent()) { preGroupedSymbols = groupingKeys; }

At a minimum, there should be a comment in the method explaining why it's abstracted that way (but IMO, that's premature over-abstraction)

@martint I like the proposed code, but... it doesn't looks that nice after I fix compilation issues. Here is what I get:

List<Symbol> preGroupedSymbols = ImmutableList.of(); if (!Iterables.getOnlyElement(LocalProperties.match(child.getProperties().getLocalProperties(), ImmutableList.of(new GroupingProperty<>(groupingKeys)))).isPresent()) { preGroupedSymbols = groupingKeys; }

Iterables.getOnlyElement and ImmutableList.of make it a lot more verbose and having "! match" is counterintuitive.

I can make it less verbose by adding match override to LocalProperties:

public static <T> Optional<LocalProperty<T>> match(List<LocalProperty<T>> actuals, LocalProperty<T> desired) { return Iterables.getOnlyElement(match(actuals, ImmutableList.of(desired))); }

but that brings ! and match closer to each other so it actually reads as "if no match, then ..."

if (!LocalProperties.match(child.getProperties().getLocalProperties(), new GroupingProperty<>(groupingKeys)).isPresent()) { preGroupedSymbols = groupingKeys; }

Would renaming this method to extractPreGrouppedSymbols work better? Or do you have any other suggestion?

Hmm... yeah, that doesn't read that nicely.

If we're going to keep the method I'd suggest something like:

List<Symbol> preGroupedSymbols = ImmutableList.of(); if (isGroupedOn(groupingKeys, child.getProperties().getLocalProperties())) { preGroupedSymbols = groupingKeys; }

and

private boolean isGroupedOn(List<Symbol> columns, List<LocalProperty<Symbol>> properties) { // !isPresent() indicates the property was satisfied completely return !LocalProperties.match(properties, LocalProperties.grouped(columns)).get(0).isPresent(); }

Although, you could just do that inline and have a comment to clarify the behavior.

@martint I could do that, but...just to clarify, are you implying that I should add support for multiple grouping sets ? (the name and implementation of isGroupOn suggest that) One of the challenges in doing that would be to find queries for testing.

I'm just saying that from the point of view of the AggregationNode, one or many grouping sets doesn't matter. The computation of the grouping sets is handled by GroupIdNode, which produces an additional synthetic column the aggregation has to group on.

@martint I looked into how multiple grouping sets are implemented. Like you mentioned, we use an auxiliary GroupIdNode that

...for every input row, emits rows for each grouping set specified. The row generated will contain NULLs in the channels corresponding to the columns present in the union of all grouping columns but not present in the current grouping set.

I couldn't find where and how the rows with different values in group_id column are redirected to the right aggregators. But, assuming this happens somehow, the implementation of GroupIdOperator doesn't seem to preserve any local properties on the grouping keys and therefore doesn't allow for streaming aggregations.

Given that the presence of GroupIdNode prevents streaming aggregation, what would be the benefit of updating the StreamingAggregationOperator to handle multiple grouping sets and a group_id column?

I'm not saying we should add support for multiple grouping sets to the operator, but from the point of view of deriving properties, we shouldn't have to special case any knowledge about multiple grouping sets. "pregrouped symbols" should just indicate that certain symbols are pre-grouped. The decision of whether to use streaming should be made by the the rule that turns an aggregation that has pregrouped group-by columns + a single grouping set into a streaming agg.

@martint I can move groupingSets.size() == 1 && !Iterables.getOnlyElement(groupingSets).isEmpty() check to AggregationNode#isStreamable and inline isGroupedOn's logic you suggested here. Would that work?

Yup, that would be perfect.

martint · 2018-06-15T17:23:02Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

+    private List<Symbol> computePreGroupedSymbols(List<List<Symbol>> groupingSets, List<Symbol> groupingKeys, PlanWithProperties childWithProperties)
+    {
+        // TODO Add streaming aggregation support for multiple grouping sets
+        if (groupingSets.size() == 1 && !Iterables.getOnlyElement(groupingSets).isEmpty()) {


Why the special casing for 1 vs many grouping sets? From the point of view of the aggregation there should be no difference in how they execute. There's just an extra column containing the group id.

@martint Primarily because I don't have a use case for multiple grouping sets. I didn't want to add non-trivial functionality that I can't test.

martint · 2018-06-15T17:30:37Z

...to-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PropertyDerivations.java

@@ -383,6 +383,16 @@ public ActualProperties visitJoin(JoinNode node, List<ActualProperties> inputPro
                    constants.putAll(probeProperties.getConstants());
                    constants.putAll(buildProperties.getConstants());

+                    if (node.isCrossJoin()) {
+                        // Cross join preserves only constants from probe and build sides.
+                        // Cross join doesn't preserve sorting or grouping local properties on either side.


That's interesting. It used to preserve sorting/grouping on the left side, but I guess that broke when we implemented the optimized execution strategy that generates RLE blocks for the smaller page on either side. It also means that the NestedLoopsJoin operator is now misnamed, since it doesn't behave like a NLJ anymore -- it's now truly a CrossJoinOperator.

martint · 2018-06-15T17:33:51Z

presto-main/src/test/java/com/facebook/presto/sql/planner/assertions/JoinMatcher.java

@@ -106,6 +106,7 @@ public String toString()
    {
        return toStringHelper(this)
                .omitNullValues()
+                .add("type", joinType)


Unrelated change?

@martint Yes and no. I added this while debugging test failures. Do you want me to put it into a separate commit?

That'd be ideal. The way I think about these kinds of changes is "if I had to revert the main change due to a bug, do I also need to lose this?"

martint · 2018-06-15T17:43:04Z

...to-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PropertyDerivations.java

@@ -183,13 +183,23 @@ public ActualProperties visitEnforceSingleRow(EnforceSingleRowNode node, List<Ac
        public ActualProperties visitAssignUniqueId(AssignUniqueId node, List<ActualProperties> inputProperties)
        {
            ActualProperties properties = Iterables.getOnlyElement(inputProperties);
+
+            ImmutableList.Builder<LocalProperty<Symbol>> localPropertiesBuilder = ImmutableList.builder();


Maybe name this "newProperties" or "newLocalProperties" ? It makes the intent clearer. Also the "builder" part in the name is irrelevant (sometimes you have to do it to deconflict with other variables, but this is not such a case)

martint · 2018-06-15T17:49:54Z

...om/facebook/presto/sql/planner/iterative/rule/PushUpAssignUniqueIdThroughRemoteExchange.java

+    {
+        AssignUniqueId assignUniqueId = captures.get(ASSIGN_UNIQUE_ID);
+        PartitioningScheme partitioningScheme = node.getPartitioningScheme();
+        if (partitioningScheme.getPartitioning().getColumns().contains(assignUniqueId.getIdColumn())) {


Add a comment explaining that the partitioning being done by the remote exchange depends on the results of the id column added by AssignUniqueId, so we can't move it above.

martint · 2018-06-15T17:52:29Z

...to-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PropertyDerivations.java

@@ -183,13 +183,23 @@ public ActualProperties visitEnforceSingleRow(EnforceSingleRowNode node, List<Ac
        public ActualProperties visitAssignUniqueId(AssignUniqueId node, List<ActualProperties> inputProperties)


The commit message is still off. It mentions HashGenerationOptimizer, but that seems to be changed elsewhere.

martint · 2018-06-15T17:59:47Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        }
+    }
+
+    private static Page rearrangePage(Page page, int[] channels)


Maybe call this "extractColumns" ? rearrangePage is a bit too vague and doesn't convey what's the purpose of the method

martint · 2018-06-15T18:03:35Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        return new Page(page.getPositionCount(), newBlocks);
+    }
+
+    private void addRowsToAggregates(Page page, int startPosition, int endPosition)


It'd be clearer if endPosition were inclusive

mbasmanova · 2018-06-15T20:26:43Z

@martint addressed/replied to comments

mbasmanova · 2018-06-18T19:44:03Z

@martint comments addressed

martint

Looks good, but take a look at the test failures.

mbasmanova · 2018-06-19T01:20:22Z

@martint Thank you, Martin.

@sopel39 Karol, is this good to go?

sopel39 · 2018-06-19T08:47:44Z

...n/java/com/facebook/presto/sql/planner/iterative/rule/PushPartialAggregationThroughJoin.java

@@ -56,6 +56,11 @@

    private static boolean isSupportedAggregationNode(AggregationNode aggregationNode)
    {
+        // Don't split streaming aggregations


make it part of rule pattern

@sopel39 Isn't it already so?

private static final Pattern<AggregationNode> PATTERN = aggregation() .matching(PushPartialAggregationThroughJoin::isSupportedAggregationNode) .with(source().matching(join().capturedAs(JOIN_NODE)));

sopel39 · 2018-06-19T08:52:52Z

presto-main/src/main/java/com/facebook/presto/sql/planner/optimizations/AddLocalExchanges.java

@@ -255,7 +255,7 @@ public PlanWithProperties visitAggregation(AggregationNode node, StreamPreferred
                return planAndEnforceChildren(node, singleStream(), defaultParallelism(session));
            }

-            StreamPreferredProperties requiredProperties = parentPreferences.withDefaultParallelism(session).withPartitioning(node.getGroupingKeys());


commit title is too long.

sopel39 · 2018-06-19T08:56:57Z

presto-main/src/test/java/com/facebook/presto/sql/planner/TestLogicalPlanner.java

+    {
+        // "orders" table is naturally grouped on orderkey
+        // this grouping should survive an inner join and allow for streaming aggregation later
+        // this grouping should not survive a cross join


move 364 comment to d288aee#diff-42e96520332fe6de8a8ff605e9f8db12R380

sopel39 · 2018-06-19T08:58:52Z

presto-main/src/test/java/com/facebook/presto/sql/planner/TestLogicalPlanner.java

+        // "orders" table is naturally grouped on orderkey
+        // this grouping should survive an inner join and allow for streaming aggregation later
+        // this grouping should not survive a cross join
+        assertPlan("SELECT o.orderkey, count(*) FROM orders o, lineitem l WHERE o.orderkey=l.orderkey GROUP BY 1",


Why do you need GROUP BY 1? How can you project unaggregated o.orderkey in that case?

@sopel39 GROUP BY 1 here is equivalent to GROUP BY o.orderkey

sopel39 · 2018-06-19T09:02:21Z

...to-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PropertyDerivations.java

            if (properties.getNodePartitioning().isPresent()) {
                // preserve input (possibly preferred) partitioning
-                return properties;
+                return ActualProperties.builderFrom(properties)


Make it explicit:

ActualProperties.builder() // preserve input (possibly preferred) partitioning .global(properties) .constants(properties.getConstants()) .local(newLocalProperties.build()) .build()

sopel39 · 2018-06-19T09:36:23Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        }
+
+        if (step.isOutputPartial()) {
+            systemMemoryContext.setBytes(memorySize);


this line is never reached in current code.

sopel39 · 2018-06-19T09:36:35Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        this.groupByTypes = ImmutableList.copyOf(requireNonNull(groupByTypes, "groupByTypes is null"));
+        this.groupByChannels = Ints.toArray(requireNonNull(groupByChannels, "groupByChannels is null"));
+        this.accumulatorFactories = requireNonNull(accumulatorFactories, "accumulatorFactories is null");
+        this.step = requireNonNull(step, "step is null");


check state that step is FINAL?

sopel39 · 2018-06-19T09:41:53Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+            if (nextGroupStart < page.getPositionCount()) {
+                // current group stops somewhere in the middle of the page, so flush it
+                evaluateAndFlushGroup(page, startPosition);
+


remove empty line

sopel39 · 2018-06-19T09:41:59Z

presto-main/src/main/java/com/facebook/presto/operator/StreamingAggregationOperator.java

+        while (true) {
+            // may be equal to page.getPositionCount() if the end is not found in this page
+            int nextGroupStart = findNextGroupStart(startPosition, groupByPage);
+


remove empty line

sopel39 · 2018-06-19T09:48:04Z

presto-main/src/test/java/com/facebook/presto/sql/planner/assertions/BasePlanTest.java

@@ -92,6 +93,11 @@ public final void destroyPlanTest()
        queryRunner = null;
    }

+    public ConnectorId getCurrentConnectorId()


Use it in com.facebook.presto.sql.planner.sanity.TestValidateAggregationsWithDefaultValues#setup too

Also, fixed dormant bug in local property derivations for cross joins.

Scalar subqueries are often rewritten as follows: - Aggregation(unique, a, b) - LeftJoin - AssignUniqueId(unique) - probe (a, b) - build In this plan, aggregation input is grouped on all grouping keys and allows for single-step streaming execution. This commit updates PropertyDerivations and StreamPropertyDerivations to derive partitioned_on(unique) global property and {grouped(unique), constant(a), constant(b)} local properties for aggregation input. These changes allow AddLocalExchange to plan streaming aggregations. Specific changes are: - Update PropertyDerivations to - set {grouped(unique), constant(a), constant(b)} local properties for the output of AssignUniqueId node; - Update StreamPropertyDerivations to - set partitioned_on(unique) for the output of AssignUniqueId node;

Append (STREAMING) to Aggregate node when printing query plan. For example, EXPLAIN (TYPE DISTRIBUTED) SELECT (SELECT count(*) FROM region r2 WHERE r2.regionkey > r1.regionkey) FROM region r1; - Aggregate(STREAMING)[regionkey, unique] => [regionkey:bigint, unique:bigint, count:bigint] count := "count"("non_null") - LeftJoin[("regionkey_0" > "regionkey")] => [regionkey:bigint, unique:bigint, non_null:boolean] Distribution: REPLICATED SortExpression["regionkey_0"] - AssignUniqueId => [regionkey:bigint, unique:bigint] - TableScan[tpch:tpch:region:sf0.01, originalConstraint = true] => [regionkey:bigint]

Scalar subqueries are often rewritten as follows: - Aggregation(unique, a, b) - LeftJoin - RemoteExchange (REPARTITION) - AssignUniqueId(unique) - probe (a, b) - RemoteExchange (REPARTITION) - build In these plans, streaming aggregation is not applied because grouped(unique, a, b) local property generated by the AssignUniqueId node can't reach the Aggregation node as it gets dropped when passing through the RemoteExchange node. This commit adds an optimizer rule to push up AssignUniqueId node through the RemoteExchange to allow for streaming aggregation. It also updates HashGenerationOptimizer to avoid generating unnecessary hashes for streaming aggregations. The modified plan looks like this: - Aggregation(unique, a, b) - LeftJoin - AssignUniqueId(unique) - RemoteExchange (REPARTITION) - probe (a, b) - RemoteExchange (REPARTITION) - build

StreamingAggregationOperator applies only when aggregation source is already grouped on the grouping keys, e.g. aggregations over joins generated for the scalar subqueries. In these cases, StreamingAggregationOperator is more efficient than HashAggregationOperator as it uses less CPU and a lot less memory. Add a benchmark to compare StreamingAggregationOperator and HashAggregationOperator for pre-grouped data sources. (operatorType) (rowsPerGroup) Mode Cnt Score Error Units streaming 1 avgt 30 379.203 ± 9.431 ms/op streaming 10 avgt 30 68.950 ± 3.164 ms/op streaming 1000 avgt 30 27.623 ± 0.776 ms/op hash 1 avgt 30 451.901 ± 15.327 ms/op hash 10 avgt 30 94.244 ± 2.437 ms/op hash 1000 avgt 30 53.038 ± 0.980 ms/op

findepi · 2018-06-20T20:51:27Z

🎉

facebook-github-bot added the CLA Signed label May 31, 2018

mbasmanova force-pushed the streaming-aggregation branch 2 times, most recently from 5a70194 to c40a872 Compare June 2, 2018 00:23

mbasmanova changed the title ~~[WIP] Streaming aggregation operator~~ [WIP] Optimize aggregation in correlated scalar subquery Jun 2, 2018

mbasmanova changed the title ~~[WIP] Optimize aggregation in correlated scalar subquery~~ [WIP] Optimize aggregation in a correlated scalar subquery Jun 2, 2018

mbasmanova force-pushed the streaming-aggregation branch from c40a872 to bcdbd1f Compare June 2, 2018 01:19

mbasmanova changed the title ~~[WIP] Optimize aggregation in a correlated scalar subquery~~ Optimize aggregation in a correlated scalar subquery Jun 2, 2018

mbasmanova mentioned this pull request Jun 2, 2018

Avoid unnecessary exchange and partial aggregation in correlated scalar subquery and correlated IN predicate #8171

Closed

mbasmanova requested a review from sopel39 June 2, 2018 05:17

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findepi changed the title ~~Optimize aggregation in a correlated scalar subquery~~ Use streaming aggregation for a correlated scalar subquery Jun 11, 2018

mbasmanova force-pushed the streaming-aggregation branch from d7be4f0 to 161ad36 Compare June 12, 2018 01:53

mbasmanova force-pushed the streaming-aggregation branch from 857bc70 to 04957e2 Compare June 14, 2018 23:50

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mbasmanova force-pushed the streaming-aggregation branch from 3333ab1 to ebe3291 Compare June 19, 2018 21:23

mbasmanova mentioned this pull request Jun 20, 2018

Memory leak in com.facebook.presto.memory.ClusterMemoryManager#changeListeners #10812

Open

mbasmanova added 10 commits June 20, 2018 12:13

Add preGroupedSymbols to AggregationNode

d31cb2a

Update AddLocalExchanges to plan streaming aggregations

6c97d9f

Also, fixed dormant bug in local property derivations for cross joins.

Include join type when printing plan pattern

4c31b76

Preserve local properties of the probe when passing through a LEFT join

3a28de7

Add AggregationNode#isStreamable

ac5d37d

Add plan checker for streaming aggregations

2d4f084

mbasmanova force-pushed the streaming-aggregation branch from ebe3291 to cc916c4 Compare June 20, 2018 16:13

mbasmanova merged commit c50646e into prestodb:master Jun 20, 2018

mbasmanova deleted the streaming-aggregation branch June 20, 2018 20:33

mbasmanova mentioned this pull request Jul 3, 2018

Partial aggregation is missing when filter reduces the data to a single group #10971

Closed

sopel39 mentioned this pull request Nov 3, 2020

Use local limit instead of local Top N if stream is sorted on ordering column trinodb/trino#5372

Closed

		@@ -183,13 +183,23 @@ public ActualProperties visitEnforceSingleRow(EnforceSingleRowNode node, List<Ac
		public ActualProperties visitAssignUniqueId(AssignUniqueId node, List<ActualProperties> inputProperties)

Use streaming aggregation for a correlated scalar subquery #10731

Use streaming aggregation for a correlated scalar subquery #10731

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mbasmanova commented May 31, 2018 • edited Loading

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sopel39 Jun 6, 2018 • edited Loading

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mbasmanova commented Jun 7, 2018

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mbasmanova commented May 31, 2018 •

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sopel39 Jun 6, 2018 •

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sopel39 Jun 6, 2018 •

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sopel39 Jun 6, 2018 •

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