[Remove] Deprecated serialization logic from pipeline aggs (#4847)

Removes the deprecated readTo/writeFrom serialization logic from piepline aggs
that is no longer used as of Legacy version 7.8.

Signed-off-by: Nicholas Walter Knize <nknize@apache.org>

CHANGELOG.md

@@ -102,6 +102,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Always auto release the flood stage block ([#4703](https://github.com/opensearch-project/OpenSearch/pull/4703))
 - Remove LegacyESVersion.V_7_4_ and V_7_5_ Constants ([#4704](https://github.com/opensearch-project/OpenSearch/pull/4704))
 - Remove Legacy Version support from Snapshot/Restore Service ([#4728](https://github.com/opensearch-project/OpenSearch/pull/4728))
+- Remove deprecated serialization logic from pipeline aggs ([#4847](https://github.com/opensearch-project/OpenSearch/pull/4847))
 
 ### Fixed
 - `opensearch-service.bat start` and `opensearch-service.bat manager` failing to run ([#4289](https://github.com/opensearch-project/OpenSearch/pull/4289))

server/src/main/java/org/opensearch/plugins/SearchPlugin.java

@@ -621,52 +621,6 @@ class PipelineAggregationSpec extends SearchExtensionSpec<
         PipelineAggregationBuilder,
         ContextParser<String, ? extends PipelineAggregationBuilder>> {
         private final Map<String, Writeable.Reader<? extends InternalAggregation>> resultReaders = new TreeMap<>();
-        /**
-         * Read the aggregator from a stream.
-         * @deprecated Pipelines implemented after 7.8.0 do not need to be sent across the wire
-         */
-        @Deprecated
-        private final Writeable.Reader<? extends PipelineAggregator> aggregatorReader;
-
-        /**
-         * Specification of a {@link PipelineAggregator}.
-         *
-         * @param name holds the names by which this aggregation might be parsed. The {@link ParseField#getPreferredName()} is special as it
-         *        is the name by under which the readers are registered. So it is the name that the {@link PipelineAggregationBuilder} and
-         *        {@link PipelineAggregator} should return from {@link NamedWriteable#getWriteableName()}. It is an error if
-         *        {@link ParseField#getPreferredName()} conflicts with another registered name, including names from other plugins.
-         * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
-         *        {@link StreamInput}
-         * @param parser reads the aggregation builder from XContent
-         */
-        public PipelineAggregationSpec(
-            ParseField name,
-            Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            ContextParser<String, ? extends PipelineAggregationBuilder> parser
-        ) {
-            super(name, builderReader, parser);
-            this.aggregatorReader = null;
-        }
-
-        /**
-         * Specification of a {@link PipelineAggregator}.
-         *
-         * @param name name by which this aggregation might be parsed or deserialized. Make sure it is the name that the
-         *        {@link PipelineAggregationBuilder} and {@link PipelineAggregator} should return from
-         *        {@link NamedWriteable#getWriteableName()}.  It is an error if this name conflicts with another registered name, including
-         *        names from other plugins.
-         * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
-         *        {@link StreamInput}
-         * @param parser reads the aggregation builder from XContent
-         */
-        public PipelineAggregationSpec(
-            String name,
-            Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            ContextParser<String, ? extends PipelineAggregationBuilder> parser
-        ) {
-            super(name, builderReader, parser);
-            this.aggregatorReader = null;
-        }
 
         /**
          * Specification of a {@link PipelineAggregator}.
@@ -677,20 +631,14 @@ public PipelineAggregationSpec(
          *        {@link ParseField#getPreferredName()} conflicts with another registered name, including names from other plugins.
          * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
          *        {@link StreamInput}
-         * @param aggregatorReader reads the {@link PipelineAggregator} from a stream
          * @param parser reads the aggregation builder from XContent
-         * @deprecated Use {@link PipelineAggregationSpec#PipelineAggregationSpec(ParseField, Writeable.Reader, ContextParser)} for
-         *             pipelines implemented after 7.8.0
          */
-        @Deprecated
         public PipelineAggregationSpec(
             ParseField name,
             Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            Writeable.Reader<? extends PipelineAggregator> aggregatorReader,
             ContextParser<String, ? extends PipelineAggregationBuilder> parser
         ) {
             super(name, builderReader, parser);
-            this.aggregatorReader = aggregatorReader;
         }
 
         /**
@@ -702,20 +650,15 @@ public PipelineAggregationSpec(
          *        names from other plugins.
          * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
          *        {@link StreamInput}
-         * @param aggregatorReader reads the {@link PipelineAggregator} from a stream
          * @param parser reads the aggregation builder from XContent
-         * @deprecated Use {@link PipelineAggregationSpec#PipelineAggregationSpec(String, Writeable.Reader, ContextParser)} for pipelines
-         *             implemented after 7.8.0
+
          */
-        @Deprecated
         public PipelineAggregationSpec(
             String name,
             Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            Writeable.Reader<? extends PipelineAggregator> aggregatorReader,
             ContextParser<String, ? extends PipelineAggregationBuilder> parser
         ) {
             super(name, builderReader, parser);
-            this.aggregatorReader = aggregatorReader;
         }
 
         /**
@@ -727,19 +670,16 @@ public PipelineAggregationSpec(
          *        {@link ParseField#getPreferredName()} conflicts with another registered name, including names from other plugins.
          * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
          *        {@link StreamInput}
-         * @param aggregatorReader reads the {@link PipelineAggregator} from a stream
          * @param parser reads the aggregation builder from XContent
          * @deprecated prefer the ctor that takes a {@link ContextParser}
          */
         @Deprecated
         public PipelineAggregationSpec(
             ParseField name,
             Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            Writeable.Reader<? extends PipelineAggregator> aggregatorReader,
             PipelineAggregator.Parser parser
         ) {
             super(name, builderReader, (p, n) -> parser.parse(n, p));
-            this.aggregatorReader = aggregatorReader;
         }
 
         /**
@@ -751,18 +691,15 @@ public PipelineAggregationSpec(
          *        names from other plugins.
          * @param builderReader the reader registered for this aggregation's builder. Typically, a reference to a constructor that takes a
          *        {@link StreamInput}
-         * @param aggregatorReader reads the {@link PipelineAggregator} from a stream
          * @deprecated prefer the ctor that takes a {@link ContextParser}
          */
         @Deprecated
         public PipelineAggregationSpec(
             String name,
             Writeable.Reader<? extends PipelineAggregationBuilder> builderReader,
-            Writeable.Reader<? extends PipelineAggregator> aggregatorReader,
             PipelineAggregator.Parser parser
         ) {
             super(name, builderReader, (p, n) -> parser.parse(n, p));
-            this.aggregatorReader = aggregatorReader;
         }
 
         /**
@@ -781,15 +718,6 @@ public PipelineAggregationSpec addResultReader(String writeableName, Writeable.R
             return this;
         }
 
-        /**
-         * Read the aggregator from a stream.
-         * @deprecated Pipelines implemented after 7.8.0 do not need to be sent across the wire
-         */
-        @Deprecated
-        public Writeable.Reader<? extends PipelineAggregator> getAggregatorReader() {
-            return aggregatorReader;
-        }
-
         /**
          * Get the readers that must be registered for this aggregation's results.
          */

server/src/main/java/org/opensearch/search/SearchModule.java

@@ -211,21 +211,14 @@
 import org.opensearch.search.aggregations.metrics.ValueCountAggregationBuilder;
 import org.opensearch.search.aggregations.metrics.WeightedAvgAggregationBuilder;
 import org.opensearch.search.aggregations.pipeline.AvgBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.AvgBucketPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.BucketScriptPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.BucketScriptPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.BucketSelectorPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.BucketSelectorPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.BucketSortPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.BucketSortPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.CumulativeSumPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.CumulativeSumPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.DerivativePipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.DerivativePipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.EwmaModel;
 import org.opensearch.search.aggregations.pipeline.ExtendedStatsBucketParser;
 import org.opensearch.search.aggregations.pipeline.ExtendedStatsBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.ExtendedStatsBucketPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.HoltLinearModel;
 import org.opensearch.search.aggregations.pipeline.HoltWintersModel;
 import org.opensearch.search.aggregations.pipeline.InternalBucketMetricValue;
@@ -236,24 +229,15 @@
 import org.opensearch.search.aggregations.pipeline.InternalStatsBucket;
 import org.opensearch.search.aggregations.pipeline.LinearModel;
 import org.opensearch.search.aggregations.pipeline.MaxBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.MaxBucketPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.MinBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.MinBucketPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.MovAvgModel;
 import org.opensearch.search.aggregations.pipeline.MovAvgPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.MovAvgPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.MovFnPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.MovFnPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.PercentilesBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.PercentilesBucketPipelineAggregator;
-import org.opensearch.search.aggregations.pipeline.PipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.SerialDiffPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.SerialDiffPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.SimpleModel;
 import org.opensearch.search.aggregations.pipeline.StatsBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.StatsBucketPipelineAggregator;
 import org.opensearch.search.aggregations.pipeline.SumBucketPipelineAggregationBuilder;
-import org.opensearch.search.aggregations.pipeline.SumBucketPipelineAggregator;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
 import org.opensearch.search.fetch.FetchPhase;
 import org.opensearch.search.fetch.FetchSubPhase;
@@ -710,15 +694,13 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 DerivativePipelineAggregationBuilder.NAME,
                 DerivativePipelineAggregationBuilder::new,
-                DerivativePipelineAggregator::new,
                 DerivativePipelineAggregationBuilder::parse
             ).addResultReader(InternalDerivative::new)
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 MaxBucketPipelineAggregationBuilder.NAME,
                 MaxBucketPipelineAggregationBuilder::new,
-                MaxBucketPipelineAggregator::new,
                 MaxBucketPipelineAggregationBuilder.PARSER
             )
                 // This bucket is used by many pipeline aggreations.
@@ -728,7 +710,6 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 MinBucketPipelineAggregationBuilder.NAME,
                 MinBucketPipelineAggregationBuilder::new,
-                MinBucketPipelineAggregator::new,
                 MinBucketPipelineAggregationBuilder.PARSER
             )
             /* Uses InternalBucketMetricValue */
@@ -737,7 +718,6 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 AvgBucketPipelineAggregationBuilder.NAME,
                 AvgBucketPipelineAggregationBuilder::new,
-                AvgBucketPipelineAggregator::new,
                 AvgBucketPipelineAggregationBuilder.PARSER
             )
                 // This bucket is used by many pipeline aggreations.
@@ -747,7 +727,6 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 SumBucketPipelineAggregationBuilder.NAME,
                 SumBucketPipelineAggregationBuilder::new,
-                SumBucketPipelineAggregator::new,
                 SumBucketPipelineAggregationBuilder.PARSER
             )
             /* Uses InternalSimpleValue */
@@ -756,31 +735,27 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 StatsBucketPipelineAggregationBuilder.NAME,
                 StatsBucketPipelineAggregationBuilder::new,
-                StatsBucketPipelineAggregator::new,
                 StatsBucketPipelineAggregationBuilder.PARSER
             ).addResultReader(InternalStatsBucket::new)
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 ExtendedStatsBucketPipelineAggregationBuilder.NAME,
                 ExtendedStatsBucketPipelineAggregationBuilder::new,
-                ExtendedStatsBucketPipelineAggregator::new,
                 new ExtendedStatsBucketParser()
             ).addResultReader(InternalExtendedStatsBucket::new)
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 PercentilesBucketPipelineAggregationBuilder.NAME,
                 PercentilesBucketPipelineAggregationBuilder::new,
-                PercentilesBucketPipelineAggregator::new,
                 PercentilesBucketPipelineAggregationBuilder.PARSER
             ).addResultReader(InternalPercentilesBucket::new)
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 MovAvgPipelineAggregationBuilder.NAME,
                 MovAvgPipelineAggregationBuilder::new,
-                MovAvgPipelineAggregator::new,
                 (XContentParser parser, String name) -> MovAvgPipelineAggregationBuilder.parse(
                     movingAverageModelParserRegistry,
                     name,
@@ -792,47 +767,41 @@ private void registerPipelineAggregations(List<SearchPlugin> plugins) {
             new PipelineAggregationSpec(
                 CumulativeSumPipelineAggregationBuilder.NAME,
                 CumulativeSumPipelineAggregationBuilder::new,
-                CumulativeSumPipelineAggregator::new,
                 CumulativeSumPipelineAggregationBuilder.PARSER
             )
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 BucketScriptPipelineAggregationBuilder.NAME,
                 BucketScriptPipelineAggregationBuilder::new,
-                BucketScriptPipelineAggregator::new,
                 BucketScriptPipelineAggregationBuilder.PARSER
             )
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 BucketSelectorPipelineAggregationBuilder.NAME,
                 BucketSelectorPipelineAggregationBuilder::new,
-                BucketSelectorPipelineAggregator::new,
                 BucketSelectorPipelineAggregationBuilder::parse
             )
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 BucketSortPipelineAggregationBuilder.NAME,
                 BucketSortPipelineAggregationBuilder::new,
-                BucketSortPipelineAggregator::new,
                 BucketSortPipelineAggregationBuilder::parse
             )
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 SerialDiffPipelineAggregationBuilder.NAME,
                 SerialDiffPipelineAggregationBuilder::new,
-                SerialDiffPipelineAggregator::new,
                 SerialDiffPipelineAggregationBuilder::parse
             )
         );
         registerPipelineAggregation(
             new PipelineAggregationSpec(
                 MovFnPipelineAggregationBuilder.NAME,
                 MovFnPipelineAggregationBuilder::new,
-                MovFnPipelineAggregator::new,
                 MovFnPipelineAggregationBuilder.PARSER
             )
         );
@@ -847,11 +816,6 @@ private void registerPipelineAggregation(PipelineAggregationSpec spec) {
         namedWriteables.add(
             new NamedWriteableRegistry.Entry(PipelineAggregationBuilder.class, spec.getName().getPreferredName(), spec.getReader())
         );
-        if (spec.getAggregatorReader() != null) {
-            namedWriteables.add(
-                new NamedWriteableRegistry.Entry(PipelineAggregator.class, spec.getName().getPreferredName(), spec.getAggregatorReader())
-            );
-        }
         for (Map.Entry<String, Writeable.Reader<? extends InternalAggregation>> resultReader : spec.getResultReaders().entrySet()) {
             namedWriteables.add(
                 new NamedWriteableRegistry.Entry(InternalAggregation.class, resultReader.getKey(), resultReader.getValue())

server/src/main/java/org/opensearch/search/aggregations/AggregationPhase.java

@@ -148,8 +148,7 @@ public void execute(SearchContext context) {
                 throw new AggregationExecutionException("Failed to build aggregation [" + aggregator.name() + "]", e);
             }
         }
-        context.queryResult()
-            .aggregations(new InternalAggregations(aggregations, context.request().source().aggregations()::buildPipelineTree));
+        context.queryResult().aggregations(new InternalAggregations(aggregations));
 
         // disable aggregations so that they don't run on next pages in case of scrolling
         context.aggregations(null);