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Posted to commits@druid.apache.org by GitBox <gi...@apache.org> on 2021/06/02 09:25:10 UTC
[GitHub] [druid] rohangarg commented on a change in pull request #11241: STRING_AGG SQL aggregator function
rohangarg commented on a change in pull request #11241:
URL: https://github.com/apache/druid/pull/11241#discussion_r643765712
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File path: sql/src/main/java/org/apache/druid/sql/calcite/aggregation/builtin/StringSqlAggregator.java
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@@ -0,0 +1,219 @@
+/*
+ * 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.sql.calcite.aggregation.builtin;
+
+import com.google.common.collect.ImmutableSet;
+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.InferTypes;
+import org.apache.calcite.sql.type.OperandTypes;
+import org.apache.calcite.sql.type.SqlTypeFamily;
+import org.apache.calcite.sql.type.SqlTypeName;
+import org.apache.calcite.util.Optionality;
+import org.apache.druid.java.util.common.HumanReadableBytes;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.math.expr.ExprMacroTable;
+import org.apache.druid.query.aggregation.ExpressionLambdaAggregatorFactory;
+import org.apache.druid.query.aggregation.FilteredAggregatorFactory;
+import org.apache.druid.query.filter.NotDimFilter;
+import org.apache.druid.query.filter.SelectorDimFilter;
+import org.apache.druid.segment.VirtualColumn;
+import org.apache.druid.segment.column.RowSignature;
+import org.apache.druid.segment.column.ValueType;
+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.Calcites;
+import org.apache.druid.sql.calcite.planner.PlannerContext;
+import org.apache.druid.sql.calcite.rel.VirtualColumnRegistry;
+
+import javax.annotation.Nullable;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class StringSqlAggregator implements SqlAggregator
+{
+ private static final String NAME = "STRING_AGG";
+ private static final SqlAggFunction FUNCTION = new StringAggFunction();
+
+ @Override
+ public SqlAggFunction calciteFunction()
+ {
+ return FUNCTION;
+ }
+
+ @Nullable
+ @Override
+ public Aggregation toDruidAggregation(
+ PlannerContext plannerContext,
+ RowSignature rowSignature,
+ VirtualColumnRegistry virtualColumnRegistry,
+ RexBuilder rexBuilder,
+ String name,
+ AggregateCall aggregateCall,
+ Project project,
+ List<Aggregation> existingAggregations,
+ boolean finalizeAggregations
+ )
+ {
+ final List<DruidExpression> arguments = aggregateCall
+ .getArgList()
+ .stream()
+ .map(i -> Expressions.fromFieldAccess(rowSignature, project, i))
+ .map(rexNode -> Expressions.toDruidExpression(plannerContext, rowSignature, rexNode))
+ .collect(Collectors.toList());
+
+ if (arguments.stream().anyMatch(Objects::isNull)) {
+ return null;
+ }
+
+ RexNode separatorNode = Expressions.fromFieldAccess(
+ rowSignature,
+ project,
+ aggregateCall.getArgList().get(1)
+ );
+ if (!separatorNode.isA(SqlKind.LITERAL)) {
+ // separator must be a literal
+ return null;
+ }
+ String separator = RexLiteral.stringValue(separatorNode);
+
+ if (separator == null) {
+ // separator must not be null
+ return null;
+ }
+
+ Integer maxSizeBytes = null;
+ if (arguments.size() > 2) {
+ RexNode maxBytes = Expressions.fromFieldAccess(
+ rowSignature,
+ project,
+ aggregateCall.getArgList().get(2)
+ );
+ if (!maxBytes.isA(SqlKind.LITERAL)) {
+ // maxBytes must be a literal
+ return null;
+ }
+ maxSizeBytes = ((Number) RexLiteral.value(maxBytes)).intValue();
+ }
+ final DruidExpression arg = arguments.get(0);
+ final ExprMacroTable macroTable = plannerContext.getExprMacroTable();
+
+ final String initialvalue = "[]";
+ final ValueType elementType = ValueType.STRING;
+ final String fieldName;
+ if (arg.isDirectColumnAccess()) {
+ fieldName = arg.getDirectColumn();
+ } else {
+ VirtualColumn vc = virtualColumnRegistry.getOrCreateVirtualColumnForExpression(plannerContext, arg, elementType);
+ fieldName = vc.getOutputName();
+ }
+
+ final String finalizer = StringUtils.format("if(array_length(o) == 0, null, array_to_string(o, '%s'))", separator);
+ final NotDimFilter dimFilter = new NotDimFilter(new SelectorDimFilter(fieldName, null, null));
+ if (aggregateCall.isDistinct()) {
+ return Aggregation.create(
+ // string_agg ignores nulls
+ new FilteredAggregatorFactory(
+ new ExpressionLambdaAggregatorFactory(
+ name,
+ ImmutableSet.of(fieldName),
+ null,
+ initialvalue,
+ null,
+ StringUtils.format("array_set_add(\"__acc\", \"%s\")", fieldName),
+ StringUtils.format("array_set_add_all(\"__acc\", \"%s\")", name),
+ null,
+ finalizer,
+ maxSizeBytes != null ? new HumanReadableBytes(maxSizeBytes) : null,
+ macroTable
+ ),
+ dimFilter
+ )
+ );
+ } else {
+ return Aggregation.create(
+ // string_agg ignores nulls
+ new FilteredAggregatorFactory(
+ new ExpressionLambdaAggregatorFactory(
+ name,
+ ImmutableSet.of(fieldName),
+ null,
+ initialvalue,
+ null,
+ StringUtils.format("array_append(\"__acc\", \"%s\")", fieldName),
+ StringUtils.format("array_concat(\"__acc\", \"%s\")", name),
+ null,
+ finalizer,
+ maxSizeBytes != null ? new HumanReadableBytes(maxSizeBytes) : null,
+ macroTable
+ ),
+ dimFilter
+ )
+ );
+ }
+ }
+
+ private static class StringAggFunction extends SqlAggFunction
+ {
+ StringAggFunction()
+ {
+ super(
+ NAME,
+ null,
+ SqlKind.OTHER_FUNCTION,
+ opBinding ->
+ Calcites.createSqlTypeWithNullability(opBinding.getTypeFactory(), SqlTypeName.VARCHAR, true),
+ InferTypes.ANY_NULLABLE,
+ OperandTypes.or(
+ OperandTypes.and(
+ OperandTypes.sequence(
+ StringUtils.format("'%s'(expr, separator)", NAME),
+ OperandTypes.ANY,
+ OperandTypes.LITERAL
Review comment:
does this also take care of the cases if the literal is wrapped in a scalar function (like `concat('a', 'b')`)?
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