Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/34#discussion_r23275041
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/compile/IndexColumnExpressionCompiler.java
---
@@ -0,0 +1,311 @@
+/*
+ * 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.phoenix.compile;
+
+import java.sql.SQLException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.hadoop.hbase.client.Scan;
+import org.apache.phoenix.compile.GroupByCompiler.GroupBy;
+import org.apache.phoenix.expression.ColumnExpression;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.parse.AddParseNode;
+import org.apache.phoenix.parse.AndParseNode;
+import org.apache.phoenix.parse.ArrayAllComparisonNode;
+import org.apache.phoenix.parse.ArrayAnyComparisonNode;
+import org.apache.phoenix.parse.ArrayElemRefNode;
+import org.apache.phoenix.parse.CaseParseNode;
+import org.apache.phoenix.parse.CastParseNode;
+import org.apache.phoenix.parse.ColumnDef;
+import org.apache.phoenix.parse.ColumnParseNode;
+import org.apache.phoenix.parse.ComparisonParseNode;
+import org.apache.phoenix.parse.DivideParseNode;
+import org.apache.phoenix.parse.FunctionParseNode;
+import org.apache.phoenix.parse.ModulusParseNode;
+import org.apache.phoenix.parse.MultiplyParseNode;
+import org.apache.phoenix.parse.NamedTableNode;
+import org.apache.phoenix.parse.NotParseNode;
+import org.apache.phoenix.parse.OrParseNode;
+import org.apache.phoenix.parse.ParseNode;
+import org.apache.phoenix.parse.ParseNodeFactory;
+import org.apache.phoenix.parse.RowValueConstructorParseNode;
+import org.apache.phoenix.parse.SQLParser;
+import org.apache.phoenix.parse.StringConcatParseNode;
+import org.apache.phoenix.parse.SubtractParseNode;
+import org.apache.phoenix.parse.TableName;
+import org.apache.phoenix.schema.PColumn;
+import org.apache.phoenix.schema.PTable;
+import org.apache.phoenix.schema.PTableType;
+import org.apache.phoenix.schema.types.PDataType;
+import org.apache.phoenix.util.IndexUtil;
+
+import com.google.common.collect.Maps;
+
+/**
+ * Visitor that checks if nodes other than ColumnParseNode are present as
an expression in an index. If the expression
+ * is present, then the node is not visited but processed as a
ColumnParseNode.
+ */
+public class IndexColumnExpressionCompiler extends ExpressionCompiler {
+
+ private static final ParseNodeFactory FACTORY = new ParseNodeFactory();
+ private final Map<String, Expression> expressionMap;
+
+ IndexColumnExpressionCompiler(StatementContext context) {
+ this(context, GroupBy.EMPTY_GROUP_BY, false);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, boolean
resolveViewConstants) {
+ this(context, GroupBy.EMPTY_GROUP_BY, resolveViewConstants);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, GroupBy
groupBy) {
+ this(context, groupBy, false);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, GroupBy
groupBy, boolean resolveViewConstants) {
+ super(context, groupBy, resolveViewConstants);
+ expressionMap =
Maps.newHashMapWithExpectedSize(context.getCurrentTable().getTable().getColumns().size());
+ for (PColumn column :
context.getCurrentTable().getTable().getColumns()) {
+ if (column.getExpressionStr() != null) {
+ Expression expression = null;
+ try {
+ ParseNode parseNode =
SQLParser.parseCondition(column.getExpressionStr());
+ expression = getExpression(parseNode);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+ expressionMap.put(column.getExpressionStr(), expression);
+ }
+ }
+ }
+
+ /**
+ * Returns the compiled expression
+ *
+ * @param node
+ * data table parse node
+ */
+ private Expression getExpression(ParseNode node) throws SQLException {
+ PTable indexTable = this.context.getCurrentTable().getTable();
+ NamedTableNode dataTableNode = NamedTableNode.create(null,
TableName.create(indexTable.getParentSchemaName()
+ .getString(),
indexTable.getParentTableName().getString()), Collections.<ColumnDef>
emptyList());
+ ColumnResolver resolver = FromCompiler.getResolver(dataTableNode,
this.context.getConnection());
+ StatementContext context = new
StatementContext(this.context.getStatement(), resolver, new Scan(),
+ new SequenceManager(this.context.getStatement()));
+ ExpressionCompiler expressionCompiler = new
ExpressionCompiler(context);
+ return node.accept(expressionCompiler);
+ }
+
+ /**
+ * @return true if current table is an index and there is an
expression that matches the given node
+ */
+ private boolean matchesIndexedExpression(ParseNode node) throws
SQLException {
+ if (context.getCurrentTable().getTable().getType() !=
PTableType.INDEX) {
+ return false;
+ }
+ DataTableNodeRewriter statementRewriter = new
DataTableNodeRewriter();
+ ParseNode dataTableParseNode = node.accept(statementRewriter);
+ Expression dataTableExpression = getExpression(dataTableParseNode);
+ return expressionMap.containsKey(dataTableExpression.toString());
+ }
+
+ private Expression convertAndVisitParseNode(ParseNode node) throws
SQLException {
+ DataTableNodeRewriter statementRewriter = new
DataTableNodeRewriter();
+ ParseNode dataTableParseNode = node.accept(statementRewriter);
+ Expression expression = getExpression(dataTableParseNode);
+ ColumnParseNode columnParseNode = new ColumnParseNode(null,
IndexUtil.getIndexColumnName(null,
+ expression.toString()), null);
+ PDataType expressionType = expression.getDataType();
+ PDataType indexColType =
IndexUtil.getIndexColumnDataType(expression.isNullable(),
expression.getDataType());
+ // if data type of expression is different from the index column
data type, cast the to expression type
+ if (indexColType != expressionType) {
--- End diff --
That's just one of the conversions we do. I'd rather not duplicate the
logic here. I think if we just use the IndexStatementRewriter to rewrite the
functional expression, we can compare apples-to-apples and just check for
equality on the way out of the visitLeave methods. Can't seem to find my
earlier comment, but also, don't duplicate all the visitEnter/visitLeave
methods. Instead, make the ExpressionCompiler.wrapGroupByExpression() method
public and override it here (rename it to something more general like
transformExpression too).
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