jon-wei commented on a change in pull request #8100: SQL support for t-digest based sketch aggregators URL: https://github.com/apache/incubator-druid/pull/8100#discussion_r309914605
########## File path: extensions-contrib/tdigestsketch/src/main/java/org/apache/druid/query/aggregation/tdigestsketch/sql/TDigestSketchQuantileSqlAggregator.java ########## @@ -0,0 +1,229 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.druid.query.aggregation.tdigestsketch.sql; + +import com.google.common.collect.ImmutableList; +import org.apache.calcite.rel.core.AggregateCall; +import org.apache.calcite.rel.core.Project; +import org.apache.calcite.rex.RexBuilder; +import org.apache.calcite.rex.RexLiteral; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.sql.SqlAggFunction; +import org.apache.calcite.sql.SqlFunctionCategory; +import org.apache.calcite.sql.SqlKind; +import org.apache.calcite.sql.type.OperandTypes; +import org.apache.calcite.sql.type.ReturnTypes; +import org.apache.calcite.sql.type.SqlTypeFamily; +import org.apache.calcite.sql.type.SqlTypeName; +import org.apache.druid.java.util.common.StringUtils; +import org.apache.druid.query.aggregation.AggregatorFactory; +import org.apache.druid.query.aggregation.post.FieldAccessPostAggregator; +import org.apache.druid.query.aggregation.tdigestsketch.TDigestSketchAggregatorFactory; +import org.apache.druid.query.aggregation.tdigestsketch.TDigestSketchToQuantilePostAggregator; +import org.apache.druid.segment.VirtualColumn; +import org.apache.druid.segment.virtual.ExpressionVirtualColumn; +import org.apache.druid.sql.calcite.aggregation.Aggregation; +import org.apache.druid.sql.calcite.aggregation.SqlAggregator; +import org.apache.druid.sql.calcite.expression.DruidExpression; +import org.apache.druid.sql.calcite.expression.Expressions; +import org.apache.druid.sql.calcite.planner.PlannerContext; +import org.apache.druid.sql.calcite.rel.VirtualColumnRegistry; +import org.apache.druid.sql.calcite.table.RowSignature; + +import javax.annotation.Nullable; +import java.util.ArrayList; +import java.util.List; + +public class TDigestSketchQuantileSqlAggregator implements SqlAggregator +{ + private static final SqlAggFunction FUNCTION_INSTANCE = new TDigestSketchQuantileSqlAggFunction(); + private static final String NAME = "TDIGEST_QUANTILE"; + + @Override + public SqlAggFunction calciteFunction() + { + return FUNCTION_INSTANCE; + } + + @Nullable + @Override + public Aggregation toDruidAggregation( + final PlannerContext plannerContext, + final RowSignature rowSignature, + final VirtualColumnRegistry virtualColumnRegistry, + final RexBuilder rexBuilder, + final String name, + final AggregateCall aggregateCall, + final Project project, + final List<Aggregation> existingAggregations, + final boolean finalizeAggregations + ) + { + // This is expected to be a tdigest sketch + final DruidExpression input = Expressions.toDruidExpression( + plannerContext, + rowSignature, + Expressions.fromFieldAccess( + rowSignature, + project, + aggregateCall.getArgList().get(0) + ) + ); + if (input == null) { + return null; + } + + final AggregatorFactory aggregatorFactory; + final String histogramName = StringUtils.format("%s:agg", name); + + // this is expected to be quantile fraction + final RexNode quantileArg = Expressions.fromFieldAccess( + rowSignature, + project, + aggregateCall.getArgList().get(1) + ); + + if (!quantileArg.isA(SqlKind.LITERAL)) { + // Quantile must be a literal in order to plan. + return null; + } + + final double quantile = ((Number) RexLiteral.value(quantileArg)).floatValue(); + Integer compression = null; + if (aggregateCall.getArgList().size() > 2) { + final RexNode compressionArg = Expressions.fromFieldAccess( + rowSignature, + project, + aggregateCall.getArgList().get(2) + ); + compression = ((Number) RexLiteral.value(compressionArg)).intValue(); + } + + // Look for existing matching aggregatorFactory. + for (final Aggregation existing : existingAggregations) { + for (AggregatorFactory factory : existing.getAggregatorFactories()) { + if (factory instanceof TDigestSketchAggregatorFactory) { + final TDigestSketchAggregatorFactory theFactory = (TDigestSketchAggregatorFactory) factory; + + // Check input for equivalence. + final boolean inputMatches; + final VirtualColumn virtualInput = existing.getVirtualColumns() + .stream() + .filter( + virtualColumn -> + virtualColumn.getOutputName() + .equals(theFactory.getFieldName()) + ) + .findFirst() + .orElse(null); + + if (virtualInput == null) { + inputMatches = input.isDirectColumnAccess() + && input.getDirectColumn().equals(theFactory.getFieldName()); + } else { + inputMatches = ((ExpressionVirtualColumn) virtualInput).getExpression() + .equals(input.getExpression()); + } + + if (inputMatches) { Review comment: Ah, it should just check compression ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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