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Posted to commits@kylin.apache.org by ma...@apache.org on 2016/06/25 11:12:18 UTC

[17/18] kylin git commit: KYLIN-1821 Reformat all of the java files and enable checkstyle to enforce code formatting

http://git-wip-us.apache.org/repos/asf/kylin/blob/5d4982e2/atopcalcite/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
----------------------------------------------------------------------
diff --git a/atopcalcite/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java b/atopcalcite/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
index aed7c27..34c97fa 100644
--- a/atopcalcite/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
+++ b/atopcalcite/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
@@ -18,6 +18,26 @@
 
 package org.apache.calcite.sql2rel;
 
+import static org.apache.calcite.sql.SqlUtil.stripAs;
+import static org.apache.calcite.util.Static.RESOURCE;
+
+import java.lang.reflect.Type;
+import java.math.BigDecimal;
+import java.util.AbstractList;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
 import org.apache.calcite.avatica.util.Spaces;
 import org.apache.calcite.linq4j.Ord;
 import org.apache.calcite.plan.Convention;
@@ -168,26 +188,6 @@ import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 
-import java.lang.reflect.Type;
-import java.math.BigDecimal;
-import java.util.AbstractList;
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Deque;
-import java.util.EnumSet;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.TreeSet;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import static org.apache.calcite.sql.SqlUtil.stripAs;
-import static org.apache.calcite.util.Static.RESOURCE;
-
 /*
  * OVERRIDE POINT:
  * - getInSubqueryThreshold(), was `20`, now `Integer.MAX_VALUE`
@@ -204,4825 +204,3997 @@ import static org.apache.calcite.util.Static.RESOURCE;
  * {@link #convertExpression(SqlNode)}.
  */
 public class SqlToRelConverter {
-  //~ Static fields/initializers ---------------------------------------------
-
-  protected static final Logger SQL2REL_LOGGER =
-      CalciteTrace.getSqlToRelTracer();
-
-  private static final BigDecimal TWO = BigDecimal.valueOf(2L);
-
-  /** Size of the smallest IN list that will be converted to a semijoin to a
-   * static table. */
-  public static final int IN_SUBQUERY_THRESHOLD = 20;
-
-  //~ Instance fields --------------------------------------------------------
-
-  protected final SqlValidator validator;
-  protected final RexBuilder rexBuilder;
-  protected final Prepare.CatalogReader catalogReader;
-  protected final RelOptCluster cluster;
-  private DefaultValueFactory defaultValueFactory;
-  private SubqueryConverter subqueryConverter;
-  protected final List<RelNode> leaves = new ArrayList<>();
-  private final List<SqlDynamicParam> dynamicParamSqlNodes = new ArrayList<>();
-  private final SqlOperatorTable opTab;
-  private boolean shouldConvertTableAccess;
-  protected final RelDataTypeFactory typeFactory;
-  private final SqlNodeToRexConverter exprConverter;
-  private boolean decorrelationEnabled;
-  private boolean trimUnusedFields;
-  private boolean shouldCreateValuesRel;
-  private boolean isExplain;
-  private int nDynamicParamsInExplain;
-
-  /**
-   * Fields used in name resolution for correlated subqueries.
-   */
-  private final Map<CorrelationId, DeferredLookup> mapCorrelToDeferred =
-      new HashMap<>();
-
-  /**
-   * Stack of names of datasets requested by the <code>
-   * TABLE(SAMPLE(&lt;datasetName&gt;, &lt;query&gt;))</code> construct.
-   */
-  private final Deque<String> datasetStack = new ArrayDeque<>();
-
-  /**
-   * Mapping of non-correlated subqueries that have been converted to their
-   * equivalent constants. Used to avoid re-evaluating the subquery if it's
-   * already been evaluated.
-   */
-  private final Map<SqlNode, RexNode> mapConvertedNonCorrSubqs =
-      new HashMap<>();
-
-  public final RelOptTable.ViewExpander viewExpander;
-
-  /** Whether to expand sub-queries. If false, each sub-query becomes a
-   * {@link org.apache.calcite.rex.RexSubQuery}. */
-  private boolean expand = true;
-
-  //~ Constructors -----------------------------------------------------------
-  /**
-   * Creates a converter.
-   *
-   * @param viewExpander    Preparing statement
-   * @param validator       Validator
-   * @param catalogReader   Schema
-   * @param planner         Planner
-   * @param rexBuilder      Rex builder
-   * @param convertletTable Expression converter
-   */
-  @Deprecated // will be removed before 2.0
-  public SqlToRelConverter(
-      RelOptTable.ViewExpander viewExpander,
-      SqlValidator validator,
-      Prepare.CatalogReader catalogReader,
-      RelOptPlanner planner,
-      RexBuilder rexBuilder,
-      SqlRexConvertletTable convertletTable) {
-    this(viewExpander, validator, catalogReader,
-        RelOptCluster.create(planner, rexBuilder), convertletTable);
-  }
-
-  /* Creates a converter. */
-  public SqlToRelConverter(
-      RelOptTable.ViewExpander viewExpander,
-      SqlValidator validator,
-      Prepare.CatalogReader catalogReader,
-      RelOptCluster cluster,
-      SqlRexConvertletTable convertletTable) {
-    this.viewExpander = viewExpander;
-    this.opTab =
-        (validator
-            == null) ? SqlStdOperatorTable.instance()
-            : validator.getOperatorTable();
-    this.validator = validator;
-    this.catalogReader = catalogReader;
-    this.defaultValueFactory = new NullDefaultValueFactory();
-    this.subqueryConverter = new NoOpSubqueryConverter();
-    this.rexBuilder = cluster.getRexBuilder();
-    this.typeFactory = rexBuilder.getTypeFactory();
-    this.cluster = Preconditions.checkNotNull(cluster);
-    this.shouldConvertTableAccess = true;
-    this.exprConverter =
-        new SqlNodeToRexConverterImpl(convertletTable);
-    decorrelationEnabled = true;
-    trimUnusedFields = false;
-    shouldCreateValuesRel = true;
-    isExplain = false;
-    nDynamicParamsInExplain = 0;
-  }
-
-  //~ Methods ----------------------------------------------------------------
-
-  /**
-   * @return the RelOptCluster in use.
-   */
-  public RelOptCluster getCluster() {
-    return cluster;
-  }
-
-  /**
-   * Returns the row-expression builder.
-   */
-  public RexBuilder getRexBuilder() {
-    return rexBuilder;
-  }
-
-  /**
-   * Returns the number of dynamic parameters encountered during translation;
-   * this must only be called after {@link #convertQuery}.
-   *
-   * @return number of dynamic parameters
-   */
-  public int getDynamicParamCount() {
-    return dynamicParamSqlNodes.size();
-  }
-
-  /**
-   * Returns the type inferred for a dynamic parameter.
-   *
-   * @param index 0-based index of dynamic parameter
-   * @return inferred type, never null
-   */
-  public RelDataType getDynamicParamType(int index) {
-    SqlNode sqlNode = dynamicParamSqlNodes.get(index);
-    if (sqlNode == null) {
-      throw Util.needToImplement("dynamic param type inference");
-    }
-    return validator.getValidatedNodeType(sqlNode);
-  }
-
-  /**
-   * Returns the current count of the number of dynamic parameters in an
-   * EXPLAIN PLAN statement.
-   *
-   * @param increment if true, increment the count
-   * @return the current count before the optional increment
-   */
-  public int getDynamicParamCountInExplain(boolean increment) {
-    int retVal = nDynamicParamsInExplain;
-    if (increment) {
-      ++nDynamicParamsInExplain;
-    }
-    return retVal;
-  }
-
-  /**
-   * @return mapping of non-correlated subqueries that have been converted to
-   * the constants that they evaluate to
-   */
-  public Map<SqlNode, RexNode> getMapConvertedNonCorrSubqs() {
-    return mapConvertedNonCorrSubqs;
-  }
-
-  /**
-   * Adds to the current map of non-correlated converted subqueries the
-   * elements from another map that contains non-correlated subqueries that
-   * have been converted by another SqlToRelConverter.
-   *
-   * @param alreadyConvertedNonCorrSubqs the other map
-   */
-  public void addConvertedNonCorrSubqs(
-      Map<SqlNode, RexNode> alreadyConvertedNonCorrSubqs) {
-    mapConvertedNonCorrSubqs.putAll(alreadyConvertedNonCorrSubqs);
-  }
-
-  /**
-   * Set a new DefaultValueFactory. To have any effect, this must be called
-   * before any convert method.
-   *
-   * @param factory new DefaultValueFactory
-   */
-  public void setDefaultValueFactory(DefaultValueFactory factory) {
-    defaultValueFactory = factory;
-  }
-
-  /**
-   * Sets a new SubqueryConverter. To have any effect, this must be called
-   * before any convert method.
-   *
-   * @param converter new SubqueryConverter
-   */
-  public void setSubqueryConverter(SubqueryConverter converter) {
-    subqueryConverter = converter;
-  }
-
-  /**
-   * Indicates that the current statement is part of an EXPLAIN PLAN statement
-   *
-   * @param nDynamicParams number of dynamic parameters in the statement
-   */
-  public void setIsExplain(int nDynamicParams) {
-    isExplain = true;
-    nDynamicParamsInExplain = nDynamicParams;
-  }
-
-  /**
-   * Controls whether table access references are converted to physical rels
-   * immediately. The optimizer doesn't like leaf rels to have
-   * {@link Convention#NONE}. However, if we are doing further conversion
-   * passes (e.g. {@link RelStructuredTypeFlattener}), then we may need to
-   * defer conversion. To have any effect, this must be called before any
-   * convert method.
-   *
-   * @param enabled true for immediate conversion (the default); false to
-   *                generate logical LogicalTableScan instances
-   */
-  public void enableTableAccessConversion(boolean enabled) {
-    shouldConvertTableAccess = enabled;
-  }
-
-  /**
-   * Controls whether instances of
-   * {@link org.apache.calcite.rel.logical.LogicalValues} are generated. These
-   * may not be supported by all physical implementations. To have any effect,
-   * this must be called before any convert method.
-   *
-   * @param enabled true to allow LogicalValues to be generated (the default);
-   *                false to force substitution of Project+OneRow instead
-   */
-  public void enableValuesRelCreation(boolean enabled) {
-    shouldCreateValuesRel = enabled;
-  }
-
-  private void checkConvertedType(SqlNode query, RelNode result) {
-    if (query.isA(SqlKind.DML)) {
-      return;
-    }
-    // Verify that conversion from SQL to relational algebra did
-    // not perturb any type information.  (We can't do this if the
-    // SQL statement is something like an INSERT which has no
-    // validator type information associated with its result,
-    // hence the namespace check above.)
-    final List<RelDataTypeField> validatedFields =
-        validator.getValidatedNodeType(query).getFieldList();
-    final RelDataType validatedRowType =
-        validator.getTypeFactory().createStructType(
-            Pair.right(validatedFields),
-            SqlValidatorUtil.uniquify(Pair.left(validatedFields)));
-
-    final List<RelDataTypeField> convertedFields =
-        result.getRowType().getFieldList().subList(0, validatedFields.size());
-    final RelDataType convertedRowType =
-        validator.getTypeFactory().createStructType(convertedFields);
-
-    if (!RelOptUtil.equal("validated row type", validatedRowType,
-        "converted row type", convertedRowType, Litmus.IGNORE)) {
-      throw new AssertionError("Conversion to relational algebra failed to "
-          + "preserve datatypes:\n"
-          + "validated type:\n"
-          + validatedRowType.getFullTypeString()
-          + "\nconverted type:\n"
-          + convertedRowType.getFullTypeString()
-          + "\nrel:\n"
-          + RelOptUtil.toString(result));
-    }
-  }
-
-  public RelNode flattenTypes(
-      RelNode rootRel,
-      boolean restructure) {
-    RelStructuredTypeFlattener typeFlattener =
-        new RelStructuredTypeFlattener(rexBuilder, createToRelContext());
-    return typeFlattener.rewrite(rootRel, restructure);
-  }
-
-  /**
-   * If subquery is correlated and decorrelation is enabled, performs
-   * decorrelation.
-   *
-   * @param query   Query
-   * @param rootRel Root relational expression
-   * @return New root relational expression after decorrelation
-   */
-  public RelNode decorrelate(SqlNode query, RelNode rootRel) {
-    if (!enableDecorrelation()) {
-      return rootRel;
-    }
-    final RelNode result = decorrelateQuery(rootRel);
-    if (result != rootRel) {
-      checkConvertedType(query, result);
-    }
-    return result;
-  }
-
-  /**
-   * Walks over a tree of relational expressions, replacing each
-   * {@link RelNode} with a 'slimmed down' relational expression that projects
-   * only the fields required by its consumer.
-   *
-   * <p>This may make things easier for the optimizer, by removing crud that
-   * would expand the search space, but is difficult for the optimizer itself
-   * to do it, because optimizer rules must preserve the number and type of
-   * fields. Hence, this transform that operates on the entire tree, similar
-   * to the {@link RelStructuredTypeFlattener type-flattening transform}.
-   *
-   * <p>Currently this functionality is disabled in farrago/luciddb; the
-   * default implementation of this method does nothing.
-   *
-   * @param ordered Whether the relational expression must produce results in
-   * a particular order (typically because it has an ORDER BY at top level)
-   * @param rootRel Relational expression that is at the root of the tree
-   * @return Trimmed relational expression
-   */
-  public RelNode trimUnusedFields(boolean ordered, RelNode rootRel) {
-    // Trim fields that are not used by their consumer.
-    if (isTrimUnusedFields()) {
-      final RelFieldTrimmer trimmer = newFieldTrimmer();
-      final List<RelCollation> collations =
-          rootRel.getTraitSet().getTraits(RelCollationTraitDef.INSTANCE);
-      rootRel = trimmer.trim(rootRel);
-      if (!ordered
-          && collations != null
-          && !collations.isEmpty()
-          && !collations.equals(ImmutableList.of(RelCollations.EMPTY))) {
-        final RelTraitSet traitSet = rootRel.getTraitSet()
-            .replace(RelCollationTraitDef.INSTANCE, collations);
-        rootRel = rootRel.copy(traitSet, rootRel.getInputs());
-      }
-      boolean dumpPlan = SQL2REL_LOGGER.isLoggable(Level.FINE);
-      if (dumpPlan) {
-        SQL2REL_LOGGER.fine(
-            RelOptUtil.dumpPlan(
-                "Plan after trimming unused fields",
-                rootRel,
-                false,
-                SqlExplainLevel.EXPPLAN_ATTRIBUTES));
-      }
+    //~ Static fields/initializers ---------------------------------------------
+
+    protected static final Logger SQL2REL_LOGGER = CalciteTrace.getSqlToRelTracer();
+
+    private static final BigDecimal TWO = BigDecimal.valueOf(2L);
+
+    /** Size of the smallest IN list that will be converted to a semijoin to a
+     * static table. */
+    public static final int IN_SUBQUERY_THRESHOLD = 20;
+
+    //~ Instance fields --------------------------------------------------------
+
+    protected final SqlValidator validator;
+    protected final RexBuilder rexBuilder;
+    protected final Prepare.CatalogReader catalogReader;
+    protected final RelOptCluster cluster;
+    private DefaultValueFactory defaultValueFactory;
+    private SubqueryConverter subqueryConverter;
+    protected final List<RelNode> leaves = new ArrayList<>();
+    private final List<SqlDynamicParam> dynamicParamSqlNodes = new ArrayList<>();
+    private final SqlOperatorTable opTab;
+    private boolean shouldConvertTableAccess;
+    protected final RelDataTypeFactory typeFactory;
+    private final SqlNodeToRexConverter exprConverter;
+    private boolean decorrelationEnabled;
+    private boolean trimUnusedFields;
+    private boolean shouldCreateValuesRel;
+    private boolean isExplain;
+    private int nDynamicParamsInExplain;
+
+    /**
+     * Fields used in name resolution for correlated subqueries.
+     */
+    private final Map<CorrelationId, DeferredLookup> mapCorrelToDeferred = new HashMap<>();
+
+    /**
+     * Stack of names of datasets requested by the <code>
+     * TABLE(SAMPLE(&lt;datasetName&gt;, &lt;query&gt;))</code> construct.
+     */
+    private final Deque<String> datasetStack = new ArrayDeque<>();
+
+    /**
+     * Mapping of non-correlated subqueries that have been converted to their
+     * equivalent constants. Used to avoid re-evaluating the subquery if it's
+     * already been evaluated.
+     */
+    private final Map<SqlNode, RexNode> mapConvertedNonCorrSubqs = new HashMap<>();
+
+    public final RelOptTable.ViewExpander viewExpander;
+
+    /** Whether to expand sub-queries. If false, each sub-query becomes a
+     * {@link org.apache.calcite.rex.RexSubQuery}. */
+    private boolean expand = true;
+
+    //~ Constructors -----------------------------------------------------------
+    /**
+     * Creates a converter.
+     *
+     * @param viewExpander    Preparing statement
+     * @param validator       Validator
+     * @param catalogReader   Schema
+     * @param planner         Planner
+     * @param rexBuilder      Rex builder
+     * @param convertletTable Expression converter
+     */
+    @Deprecated // will be removed before 2.0
+    public SqlToRelConverter(RelOptTable.ViewExpander viewExpander, SqlValidator validator, Prepare.CatalogReader catalogReader, RelOptPlanner planner, RexBuilder rexBuilder, SqlRexConvertletTable convertletTable) {
+        this(viewExpander, validator, catalogReader, RelOptCluster.create(planner, rexBuilder), convertletTable);
+    }
+
+    /* Creates a converter. */
+    public SqlToRelConverter(RelOptTable.ViewExpander viewExpander, SqlValidator validator, Prepare.CatalogReader catalogReader, RelOptCluster cluster, SqlRexConvertletTable convertletTable) {
+        this.viewExpander = viewExpander;
+        this.opTab = (validator == null) ? SqlStdOperatorTable.instance() : validator.getOperatorTable();
+        this.validator = validator;
+        this.catalogReader = catalogReader;
+        this.defaultValueFactory = new NullDefaultValueFactory();
+        this.subqueryConverter = new NoOpSubqueryConverter();
+        this.rexBuilder = cluster.getRexBuilder();
+        this.typeFactory = rexBuilder.getTypeFactory();
+        this.cluster = Preconditions.checkNotNull(cluster);
+        this.shouldConvertTableAccess = true;
+        this.exprConverter = new SqlNodeToRexConverterImpl(convertletTable);
+        decorrelationEnabled = true;
+        trimUnusedFields = false;
+        shouldCreateValuesRel = true;
+        isExplain = false;
+        nDynamicParamsInExplain = 0;
+    }
+
+    //~ Methods ----------------------------------------------------------------
+
+    /**
+     * @return the RelOptCluster in use.
+     */
+    public RelOptCluster getCluster() {
+        return cluster;
     }
-    return rootRel;
-  }
-
-  /**
-   * Creates a RelFieldTrimmer.
-   *
-   * @return Field trimmer
-   */
-  protected RelFieldTrimmer newFieldTrimmer() {
-    final RelBuilder relBuilder =
-        RelFactories.LOGICAL_BUILDER.create(cluster, null);
-    return new RelFieldTrimmer(validator, relBuilder);
-  }
-
-  /**
-   * Converts an unvalidated query's parse tree into a relational expression.
-   *
-   * @param query           Query to convert
-   * @param needsValidation Whether to validate the query before converting;
-   *                        <code>false</code> if the query has already been
-   *                        validated.
-   * @param top             Whether the query is top-level, say if its result
-   *                        will become a JDBC result set; <code>false</code> if
-   *                        the query will be part of a view.
-   */
-  public RelRoot convertQuery(
-      SqlNode query,
-      final boolean needsValidation,
-      final boolean top) {
-    if (needsValidation) {
-      query = validator.validate(query);
+
+    /**
+     * Returns the row-expression builder.
+     */
+    public RexBuilder getRexBuilder() {
+        return rexBuilder;
     }
 
-    RelNode result = convertQueryRecursive(query, top, null).rel;
-    if (top) {
-      if (isStream(query)) {
-        result = new LogicalDelta(cluster, result.getTraitSet(), result);
-      }
+    /**
+     * Returns the number of dynamic parameters encountered during translation;
+     * this must only be called after {@link #convertQuery}.
+     *
+     * @return number of dynamic parameters
+     */
+    public int getDynamicParamCount() {
+        return dynamicParamSqlNodes.size();
     }
-    RelCollation collation = RelCollations.EMPTY;
-    if (!query.isA(SqlKind.DML)) {
-      if (isOrdered(query)) {
-        collation = requiredCollation(result);
-      }
+
+    /**
+     * Returns the type inferred for a dynamic parameter.
+     *
+     * @param index 0-based index of dynamic parameter
+     * @return inferred type, never null
+     */
+    public RelDataType getDynamicParamType(int index) {
+        SqlNode sqlNode = dynamicParamSqlNodes.get(index);
+        if (sqlNode == null) {
+            throw Util.needToImplement("dynamic param type inference");
+        }
+        return validator.getValidatedNodeType(sqlNode);
     }
-    checkConvertedType(query, result);
-
-    boolean dumpPlan = SQL2REL_LOGGER.isLoggable(Level.FINE);
-    if (dumpPlan) {
-      SQL2REL_LOGGER.fine(
-          RelOptUtil.dumpPlan(
-              "Plan after converting SqlNode to RelNode",
-              result,
-              false,
-              SqlExplainLevel.EXPPLAN_ATTRIBUTES));
+
+    /**
+     * Returns the current count of the number of dynamic parameters in an
+     * EXPLAIN PLAN statement.
+     *
+     * @param increment if true, increment the count
+     * @return the current count before the optional increment
+     */
+    public int getDynamicParamCountInExplain(boolean increment) {
+        int retVal = nDynamicParamsInExplain;
+        if (increment) {
+            ++nDynamicParamsInExplain;
+        }
+        return retVal;
     }
 
-    final RelDataType validatedRowType = validator.getValidatedNodeType(query);
-    return RelRoot.of(result, validatedRowType, query.getKind())
-        .withCollation(collation);
-  }
-
-  private static boolean isStream(SqlNode query) {
-    return query instanceof SqlSelect
-        && ((SqlSelect) query).isKeywordPresent(SqlSelectKeyword.STREAM);
-  }
-
-  public static boolean isOrdered(SqlNode query) {
-    switch (query.getKind()) {
-    case SELECT:
-      return ((SqlSelect) query).getOrderList() != null
-          && ((SqlSelect) query).getOrderList().size() > 0;
-    case WITH:
-      return isOrdered(((SqlWith) query).body);
-    case ORDER_BY:
-      return ((SqlOrderBy) query).orderList.size() > 0;
-    default:
-      return false;
+    /**
+     * @return mapping of non-correlated subqueries that have been converted to
+     * the constants that they evaluate to
+     */
+    public Map<SqlNode, RexNode> getMapConvertedNonCorrSubqs() {
+        return mapConvertedNonCorrSubqs;
     }
-  }
 
-  private RelCollation requiredCollation(RelNode r) {
-    if (r instanceof Sort) {
-      return ((Sort) r).collation;
+    /**
+     * Adds to the current map of non-correlated converted subqueries the
+     * elements from another map that contains non-correlated subqueries that
+     * have been converted by another SqlToRelConverter.
+     *
+     * @param alreadyConvertedNonCorrSubqs the other map
+     */
+    public void addConvertedNonCorrSubqs(Map<SqlNode, RexNode> alreadyConvertedNonCorrSubqs) {
+        mapConvertedNonCorrSubqs.putAll(alreadyConvertedNonCorrSubqs);
     }
-    if (r instanceof Project) {
-      return requiredCollation(((Project) r).getInput());
+
+    /**
+     * Set a new DefaultValueFactory. To have any effect, this must be called
+     * before any convert method.
+     *
+     * @param factory new DefaultValueFactory
+     */
+    public void setDefaultValueFactory(DefaultValueFactory factory) {
+        defaultValueFactory = factory;
     }
-    if (r instanceof Delta) {
-      return requiredCollation(((Delta) r).getInput());
+
+    /**
+     * Sets a new SubqueryConverter. To have any effect, this must be called
+     * before any convert method.
+     *
+     * @param converter new SubqueryConverter
+     */
+    public void setSubqueryConverter(SubqueryConverter converter) {
+        subqueryConverter = converter;
     }
-    throw new AssertionError();
-  }
-
-  /**
-   * Converts a SELECT statement's parse tree into a relational expression.
-   */
-  public RelNode convertSelect(SqlSelect select, boolean top) {
-    final SqlValidatorScope selectScope = validator.getWhereScope(select);
-    final Blackboard bb = createBlackboard(selectScope, null, top);
-    convertSelectImpl(bb, select);
-    return bb.root;
-  }
-
-  /**
-   * Factory method for creating translation workspace.
-   */
-  protected Blackboard createBlackboard(SqlValidatorScope scope,
-      Map<String, RexNode> nameToNodeMap, boolean top) {
-    return new Blackboard(scope, nameToNodeMap, top);
-  }
-
-  /**
-   * Implementation of {@link #convertSelect(SqlSelect, boolean)};
-   * derived class may override.
-   */
-  protected void convertSelectImpl(
-      final Blackboard bb,
-      SqlSelect select) {
-    convertFrom(
-        bb,
-        select.getFrom());
-    convertWhere(
-        bb,
-        select.getWhere());
-
-    final List<SqlNode> orderExprList = new ArrayList<>();
-    final List<RelFieldCollation> collationList = new ArrayList<>();
-    gatherOrderExprs(
-        bb,
-        select,
-        select.getOrderList(),
-        orderExprList,
-        collationList);
-    final RelCollation collation =
-        cluster.traitSet().canonize(RelCollations.of(collationList));
-
-    if (validator.isAggregate(select)) {
-      convertAgg(
-          bb,
-          select,
-          orderExprList);
-    } else {
-      convertSelectList(
-          bb,
-          select,
-          orderExprList);
+
+    /**
+     * Indicates that the current statement is part of an EXPLAIN PLAN statement
+     *
+     * @param nDynamicParams number of dynamic parameters in the statement
+     */
+    public void setIsExplain(int nDynamicParams) {
+        isExplain = true;
+        nDynamicParamsInExplain = nDynamicParams;
     }
 
-    if (select.isDistinct()) {
-      distinctify(bb, true);
+    /**
+     * Controls whether table access references are converted to physical rels
+     * immediately. The optimizer doesn't like leaf rels to have
+     * {@link Convention#NONE}. However, if we are doing further conversion
+     * passes (e.g. {@link RelStructuredTypeFlattener}), then we may need to
+     * defer conversion. To have any effect, this must be called before any
+     * convert method.
+     *
+     * @param enabled true for immediate conversion (the default); false to
+     *                generate logical LogicalTableScan instances
+     */
+    public void enableTableAccessConversion(boolean enabled) {
+        shouldConvertTableAccess = enabled;
     }
-    convertOrder(
-        select, bb, collation, orderExprList, select.getOffset(),
-        select.getFetch());
-    bb.setRoot(bb.root, true);
-  }
-
-  /**
-   * Having translated 'SELECT ... FROM ... [GROUP BY ...] [HAVING ...]', adds
-   * a relational expression to make the results unique.
-   *
-   * <p>If the SELECT clause contains duplicate expressions, adds
-   * {@link org.apache.calcite.rel.logical.LogicalProject}s so that we are
-   * grouping on the minimal set of keys. The performance gain isn't huge, but
-   * it is difficult to detect these duplicate expressions later.
-   *
-   * @param bb               Blackboard
-   * @param checkForDupExprs Check for duplicate expressions
-   */
-  private void distinctify(
-      Blackboard bb,
-      boolean checkForDupExprs) {
-    // Look for duplicate expressions in the project.
-    // Say we have 'select x, y, x, z'.
-    // Then dups will be {[2, 0]}
-    // and oldToNew will be {[0, 0], [1, 1], [2, 0], [3, 2]}
-    RelNode rel = bb.root;
-    if (checkForDupExprs && (rel instanceof LogicalProject)) {
-      LogicalProject project = (LogicalProject) rel;
-      final List<RexNode> projectExprs = project.getProjects();
-      final List<Integer> origins = new ArrayList<>();
-      int dupCount = 0;
-      for (int i = 0; i < projectExprs.size(); i++) {
-        int x = findExpr(projectExprs.get(i), projectExprs, i);
-        if (x >= 0) {
-          origins.add(x);
-          ++dupCount;
-        } else {
-          origins.add(i);
-        }
-      }
-      if (dupCount == 0) {
-        distinctify(bb, false);
-        return;
-      }
-
-      final Map<Integer, Integer> squished = Maps.newHashMap();
-      final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
-      final List<Pair<RexNode, String>> newProjects = Lists.newArrayList();
-      for (int i = 0; i < fields.size(); i++) {
-        if (origins.get(i) == i) {
-          squished.put(i, newProjects.size());
-          newProjects.add(RexInputRef.of2(i, fields));
-        }
-      }
-      rel =
-          LogicalProject.create(rel, Pair.left(newProjects),
-              Pair.right(newProjects));
-      bb.root = rel;
-      distinctify(bb, false);
-      rel = bb.root;
-
-      // Create the expressions to reverse the mapping.
-      // Project($0, $1, $0, $2).
-      final List<Pair<RexNode, String>> undoProjects = Lists.newArrayList();
-      for (int i = 0; i < fields.size(); i++) {
-        final int origin = origins.get(i);
-        RelDataTypeField field = fields.get(i);
-        undoProjects.add(
-            Pair.of(
-                (RexNode) new RexInputRef(
-                    squished.get(origin), field.getType()),
-                field.getName()));
-      }
-
-      rel =
-          LogicalProject.create(rel, Pair.left(undoProjects),
-              Pair.right(undoProjects));
-      bb.setRoot(
-          rel,
-          false);
-
-      return;
+
+    /**
+     * Controls whether instances of
+     * {@link org.apache.calcite.rel.logical.LogicalValues} are generated. These
+     * may not be supported by all physical implementations. To have any effect,
+     * this must be called before any convert method.
+     *
+     * @param enabled true to allow LogicalValues to be generated (the default);
+     *                false to force substitution of Project+OneRow instead
+     */
+    public void enableValuesRelCreation(boolean enabled) {
+        shouldCreateValuesRel = enabled;
     }
 
-    // Usual case: all of the expressions in the SELECT clause are
-    // different.
-    final ImmutableBitSet groupSet =
-        ImmutableBitSet.range(rel.getRowType().getFieldCount());
-    rel =
-        createAggregate(bb, false, groupSet, ImmutableList.of(groupSet),
-            ImmutableList.<AggregateCall>of());
-
-    bb.setRoot(
-        rel,
-        false);
-  }
-
-  private int findExpr(RexNode seek, List<RexNode> exprs, int count) {
-    for (int i = 0; i < count; i++) {
-      RexNode expr = exprs.get(i);
-      if (expr.toString().equals(seek.toString())) {
-        return i;
-      }
+    private void checkConvertedType(SqlNode query, RelNode result) {
+        if (query.isA(SqlKind.DML)) {
+            return;
+        }
+        // Verify that conversion from SQL to relational algebra did
+        // not perturb any type information.  (We can't do this if the
+        // SQL statement is something like an INSERT which has no
+        // validator type information associated with its result,
+        // hence the namespace check above.)
+        final List<RelDataTypeField> validatedFields = validator.getValidatedNodeType(query).getFieldList();
+        final RelDataType validatedRowType = validator.getTypeFactory().createStructType(Pair.right(validatedFields), SqlValidatorUtil.uniquify(Pair.left(validatedFields)));
+
+        final List<RelDataTypeField> convertedFields = result.getRowType().getFieldList().subList(0, validatedFields.size());
+        final RelDataType convertedRowType = validator.getTypeFactory().createStructType(convertedFields);
+
+        if (!RelOptUtil.equal("validated row type", validatedRowType, "converted row type", convertedRowType, Litmus.IGNORE)) {
+            throw new AssertionError("Conversion to relational algebra failed to " + "preserve datatypes:\n" + "validated type:\n" + validatedRowType.getFullTypeString() + "\nconverted type:\n" + convertedRowType.getFullTypeString() + "\nrel:\n" + RelOptUtil.toString(result));
+        }
     }
-    return -1;
-  }
-
-  /**
-   * Converts a query's ORDER BY clause, if any.
-   *
-   * @param select        Query
-   * @param bb            Blackboard
-   * @param collation     Collation list
-   * @param orderExprList Method populates this list with orderBy expressions
-   *                      not present in selectList
-   * @param offset        Expression for number of rows to discard before
-   *                      returning first row
-   * @param fetch         Expression for number of rows to fetch
-   */
-  protected void convertOrder(
-      SqlSelect select,
-      Blackboard bb,
-      RelCollation collation,
-      List<SqlNode> orderExprList,
-      SqlNode offset,
-      SqlNode fetch) {
-    if (select.getOrderList() == null
-        || select.getOrderList().getList().isEmpty()) {
-      assert collation.getFieldCollations().isEmpty();
-      if ((offset == null
-            || ((SqlLiteral) offset).bigDecimalValue().equals(BigDecimal.ZERO))
-          && fetch == null) {
-        return;
-      }
+
+    public RelNode flattenTypes(RelNode rootRel, boolean restructure) {
+        RelStructuredTypeFlattener typeFlattener = new RelStructuredTypeFlattener(rexBuilder, createToRelContext());
+        return typeFlattener.rewrite(rootRel, restructure);
     }
 
-    // Create a sorter using the previously constructed collations.
-    bb.setRoot(
-        LogicalSort.create(bb.root, collation,
-            offset == null ? null : convertExpression(offset),
-            fetch == null ? null : convertExpression(fetch)),
-        false);
-
-    // If extra expressions were added to the project list for sorting,
-    // add another project to remove them. But make the collation empty, because
-    // we can't represent the real collation.
-    //
-    // If it is the top node, use the real collation, but don't trim fields.
-    if (orderExprList.size() > 0 && !bb.top) {
-      final List<RexNode> exprs = new ArrayList<>();
-      final RelDataType rowType = bb.root.getRowType();
-      final int fieldCount =
-          rowType.getFieldCount() - orderExprList.size();
-      for (int i = 0; i < fieldCount; i++) {
-        exprs.add(rexBuilder.makeInputRef(bb.root, i));
-      }
-      bb.setRoot(
-          LogicalProject.create(bb.root, exprs,
-              rowType.getFieldNames().subList(0, fieldCount)),
-          false);
+    /**
+     * If subquery is correlated and decorrelation is enabled, performs
+     * decorrelation.
+     *
+     * @param query   Query
+     * @param rootRel Root relational expression
+     * @return New root relational expression after decorrelation
+     */
+    public RelNode decorrelate(SqlNode query, RelNode rootRel) {
+        if (!enableDecorrelation()) {
+            return rootRel;
+        }
+        final RelNode result = decorrelateQuery(rootRel);
+        if (result != rootRel) {
+            checkConvertedType(query, result);
+        }
+        return result;
     }
-  }
-
-  /**
-   * Returns whether a given node contains a {@link SqlInOperator}.
-   *
-   * @param node a RexNode tree
-   */
-  private static boolean containsInOperator(
-      SqlNode node) {
-    try {
-      SqlVisitor<Void> visitor =
-          new SqlBasicVisitor<Void>() {
-            public Void visit(SqlCall call) {
-              if (call.getOperator() instanceof SqlInOperator) {
-                throw new Util.FoundOne(call);
-              }
-              return super.visit(call);
+
+    /**
+     * Walks over a tree of relational expressions, replacing each
+     * {@link RelNode} with a 'slimmed down' relational expression that projects
+     * only the fields required by its consumer.
+     *
+     * <p>This may make things easier for the optimizer, by removing crud that
+     * would expand the search space, but is difficult for the optimizer itself
+     * to do it, because optimizer rules must preserve the number and type of
+     * fields. Hence, this transform that operates on the entire tree, similar
+     * to the {@link RelStructuredTypeFlattener type-flattening transform}.
+     *
+     * <p>Currently this functionality is disabled in farrago/luciddb; the
+     * default implementation of this method does nothing.
+     *
+     * @param ordered Whether the relational expression must produce results in
+     * a particular order (typically because it has an ORDER BY at top level)
+     * @param rootRel Relational expression that is at the root of the tree
+     * @return Trimmed relational expression
+     */
+    public RelNode trimUnusedFields(boolean ordered, RelNode rootRel) {
+        // Trim fields that are not used by their consumer.
+        if (isTrimUnusedFields()) {
+            final RelFieldTrimmer trimmer = newFieldTrimmer();
+            final List<RelCollation> collations = rootRel.getTraitSet().getTraits(RelCollationTraitDef.INSTANCE);
+            rootRel = trimmer.trim(rootRel);
+            if (!ordered && collations != null && !collations.isEmpty() && !collations.equals(ImmutableList.of(RelCollations.EMPTY))) {
+                final RelTraitSet traitSet = rootRel.getTraitSet().replace(RelCollationTraitDef.INSTANCE, collations);
+                rootRel = rootRel.copy(traitSet, rootRel.getInputs());
             }
-          };
-      node.accept(visitor);
-      return false;
-    } catch (Util.FoundOne e) {
-      Util.swallow(e, null);
-      return true;
-    }
-  }
-
-  /**
-   * Push down all the NOT logical operators into any IN/NOT IN operators.
-   *
-   * @param sqlNode the root node from which to look for NOT operators
-   * @return the transformed SqlNode representation with NOT pushed down.
-   */
-  private static SqlNode pushDownNotForIn(SqlNode sqlNode) {
-    if ((sqlNode instanceof SqlCall) && containsInOperator(sqlNode)) {
-      SqlCall sqlCall = (SqlCall) sqlNode;
-      if ((sqlCall.getOperator() == SqlStdOperatorTable.AND)
-          || (sqlCall.getOperator() == SqlStdOperatorTable.OR)) {
-        SqlNode[] sqlOperands = ((SqlBasicCall) sqlCall).operands;
-        for (int i = 0; i < sqlOperands.length; i++) {
-          sqlOperands[i] = pushDownNotForIn(sqlOperands[i]);
-        }
-        return sqlNode;
-      } else if (sqlCall.getOperator() == SqlStdOperatorTable.NOT) {
-        SqlNode childNode = sqlCall.operand(0);
-        assert childNode instanceof SqlCall;
-        SqlBasicCall childSqlCall = (SqlBasicCall) childNode;
-        if (childSqlCall.getOperator() == SqlStdOperatorTable.AND) {
-          SqlNode[] andOperands = childSqlCall.getOperands();
-          SqlNode[] orOperands = new SqlNode[andOperands.length];
-          for (int i = 0; i < orOperands.length; i++) {
-            orOperands[i] =
-                SqlStdOperatorTable.NOT.createCall(
-                    SqlParserPos.ZERO,
-                    andOperands[i]);
-          }
-          for (int i = 0; i < orOperands.length; i++) {
-            orOperands[i] = pushDownNotForIn(orOperands[i]);
-          }
-          return SqlStdOperatorTable.OR.createCall(SqlParserPos.ZERO,
-              orOperands[0], orOperands[1]);
-        } else if (childSqlCall.getOperator() == SqlStdOperatorTable.OR) {
-          SqlNode[] orOperands = childSqlCall.getOperands();
-          SqlNode[] andOperands = new SqlNode[orOperands.length];
-          for (int i = 0; i < andOperands.length; i++) {
-            andOperands[i] =
-                SqlStdOperatorTable.NOT.createCall(
-                    SqlParserPos.ZERO,
-                    orOperands[i]);
-          }
-          for (int i = 0; i < andOperands.length; i++) {
-            andOperands[i] = pushDownNotForIn(andOperands[i]);
-          }
-          return SqlStdOperatorTable.AND.createCall(SqlParserPos.ZERO,
-              andOperands[0], andOperands[1]);
-        } else if (childSqlCall.getOperator() == SqlStdOperatorTable.NOT) {
-          SqlNode[] notOperands = childSqlCall.getOperands();
-          assert notOperands.length == 1;
-          return pushDownNotForIn(notOperands[0]);
-        } else if (childSqlCall.getOperator() instanceof SqlInOperator) {
-          SqlNode[] inOperands = childSqlCall.getOperands();
-          SqlInOperator inOp =
-              (SqlInOperator) childSqlCall.getOperator();
-          if (inOp.isNotIn()) {
-            return SqlStdOperatorTable.IN.createCall(
-                SqlParserPos.ZERO,
-                inOperands[0],
-                inOperands[1]);
-          } else {
-            return SqlStdOperatorTable.NOT_IN.createCall(
-                SqlParserPos.ZERO,
-                inOperands[0],
-                inOperands[1]);
-          }
-        } else {
-          // childSqlCall is "leaf" node in a logical expression tree
-          // (only considering AND, OR, NOT)
-          return sqlNode;
-        }
-      } else {
-        // sqlNode is "leaf" node in a logical expression tree
-        // (only considering AND, OR, NOT)
-        return sqlNode;
-      }
-    } else {
-      // tree rooted at sqlNode does not contain inOperator
-      return sqlNode;
-    }
-  }
-
-  /**
-   * Converts a WHERE clause.
-   *
-   * @param bb    Blackboard
-   * @param where WHERE clause, may be null
-   */
-  private void convertWhere(
-      final Blackboard bb,
-      final SqlNode where) {
-    if (where == null) {
-      return;
+            boolean dumpPlan = SQL2REL_LOGGER.isLoggable(Level.FINE);
+            if (dumpPlan) {
+                SQL2REL_LOGGER.fine(RelOptUtil.dumpPlan("Plan after trimming unused fields", rootRel, false, SqlExplainLevel.EXPPLAN_ATTRIBUTES));
+            }
+        }
+        return rootRel;
     }
-    SqlNode newWhere = pushDownNotForIn(where);
-    replaceSubqueries(bb, newWhere, RelOptUtil.Logic.UNKNOWN_AS_FALSE);
-    final RexNode convertedWhere = bb.convertExpression(newWhere);
 
-    // only allocate filter if the condition is not TRUE
-    if (convertedWhere.isAlwaysTrue()) {
-      return;
+    /**
+     * Creates a RelFieldTrimmer.
+     *
+     * @return Field trimmer
+     */
+    protected RelFieldTrimmer newFieldTrimmer() {
+        final RelBuilder relBuilder = RelFactories.LOGICAL_BUILDER.create(cluster, null);
+        return new RelFieldTrimmer(validator, relBuilder);
     }
 
-    final RelNode filter = RelOptUtil.createFilter(bb.root, convertedWhere);
-    final RelNode r;
-    final CorrelationUse p = getCorrelationUse(bb, filter);
-    if (p != null) {
-      assert p.r instanceof Filter;
-      Filter f = (Filter) p.r;
-      r = LogicalFilter.create(f.getInput(), f.getCondition(),
-          ImmutableSet.of(p.id));
-    } else {
-      r = filter;
-    }
+    /**
+     * Converts an unvalidated query's parse tree into a relational expression.
+     *
+     * @param query           Query to convert
+     * @param needsValidation Whether to validate the query before converting;
+     *                        <code>false</code> if the query has already been
+     *                        validated.
+     * @param top             Whether the query is top-level, say if its result
+     *                        will become a JDBC result set; <code>false</code> if
+     *                        the query will be part of a view.
+     */
+    public RelRoot convertQuery(SqlNode query, final boolean needsValidation, final boolean top) {
+        if (needsValidation) {
+            query = validator.validate(query);
+        }
 
-    bb.setRoot(r, false);
-  }
+        RelNode result = convertQueryRecursive(query, top, null).rel;
+        if (top) {
+            if (isStream(query)) {
+                result = new LogicalDelta(cluster, result.getTraitSet(), result);
+            }
+        }
+        RelCollation collation = RelCollations.EMPTY;
+        if (!query.isA(SqlKind.DML)) {
+            if (isOrdered(query)) {
+                collation = requiredCollation(result);
+            }
+        }
+        checkConvertedType(query, result);
 
-  private void replaceSubqueries(
-      final Blackboard bb,
-      final SqlNode expr,
-      RelOptUtil.Logic logic) {
-    findSubqueries(bb, expr, logic, false);
-    for (SubQuery node : bb.subqueryList) {
-      substituteSubquery(bb, node);
-    }
-  }
+        boolean dumpPlan = SQL2REL_LOGGER.isLoggable(Level.FINE);
+        if (dumpPlan) {
+            SQL2REL_LOGGER.fine(RelOptUtil.dumpPlan("Plan after converting SqlNode to RelNode", result, false, SqlExplainLevel.EXPPLAN_ATTRIBUTES));
+        }
 
-  private void substituteSubquery(Blackboard bb, SubQuery subQuery) {
-    final RexNode expr = subQuery.expr;
-    if (expr != null) {
-      // Already done.
-      return;
+        final RelDataType validatedRowType = validator.getValidatedNodeType(query);
+        return RelRoot.of(result, validatedRowType, query.getKind()).withCollation(collation);
     }
 
-    final SqlBasicCall call;
-    final RelNode rel;
-    final SqlNode query;
-    final Pair<RelNode, Boolean> converted;
-    switch (subQuery.node.getKind()) {
-    case CURSOR:
-      convertCursor(bb, subQuery);
-      return;
-
-    case MULTISET_QUERY_CONSTRUCTOR:
-    case MULTISET_VALUE_CONSTRUCTOR:
-    case ARRAY_QUERY_CONSTRUCTOR:
-      rel = convertMultisets(ImmutableList.of(subQuery.node), bb);
-      subQuery.expr = bb.register(rel, JoinRelType.INNER);
-      return;
-
-    case IN:
-      call = (SqlBasicCall) subQuery.node;
-      query = call.operand(1);
-      if (!expand && !(query instanceof SqlNodeList)) {
-        return;
-      }
-      final SqlNode leftKeyNode = call.operand(0);
-
-      final List<RexNode> leftKeys;
-      switch (leftKeyNode.getKind()) {
-      case ROW:
-        leftKeys = Lists.newArrayList();
-        for (SqlNode sqlExpr : ((SqlBasicCall) leftKeyNode).getOperandList()) {
-          leftKeys.add(bb.convertExpression(sqlExpr));
-        }
-        break;
-      default:
-        leftKeys = ImmutableList.of(bb.convertExpression(leftKeyNode));
-      }
-
-      final boolean isNotIn = ((SqlInOperator) call.getOperator()).isNotIn();
-      if (query instanceof SqlNodeList) {
-        SqlNodeList valueList = (SqlNodeList) query;
-        if (!containsNullLiteral(valueList)
-            && valueList.size() < getInSubqueryThreshold()) {
-          // We're under the threshold, so convert to OR.
-          subQuery.expr =
-              convertInToOr(
-                  bb,
-                  leftKeys,
-                  valueList,
-                  isNotIn);
-          return;
-        }
-
-        // Otherwise, let convertExists translate
-        // values list into an inline table for the
-        // reference to Q below.
-      }
-
-      // Project out the search columns from the left side
-
-      //  Q1:
-      // "select from emp where emp.deptno in (select col1 from T)"
-      //
-      // is converted to
-      //
-      // "select from
-      //   emp inner join (select distinct col1 from T)) q
-      //   on emp.deptno = q.col1
-      //
-      // Q2:
-      // "select from emp where emp.deptno not in (Q)"
-      //
-      // is converted to
-      //
-      // "select from
-      //   emp left outer join (select distinct col1, TRUE from T) q
-      //   on emp.deptno = q.col1
-      //   where emp.deptno <> null
-      //         and q.indicator <> TRUE"
-      //
-      final boolean outerJoin = bb.subqueryNeedsOuterJoin
-          || isNotIn
-          || subQuery.logic == RelOptUtil.Logic.TRUE_FALSE_UNKNOWN;
-      final RelDataType targetRowType =
-          SqlTypeUtil.promoteToRowType(typeFactory,
-              validator.getValidatedNodeType(leftKeyNode), null);
-      converted =
-          convertExists(query, RelOptUtil.SubqueryType.IN, subQuery.logic,
-              outerJoin, targetRowType);
-      if (converted.right) {
-        // Generate
-        //    emp CROSS JOIN (SELECT COUNT(*) AS c,
-        //                       COUNT(deptno) AS ck FROM dept)
-        final RelDataType longType =
-            typeFactory.createSqlType(SqlTypeName.BIGINT);
-        final RelNode seek = converted.left.getInput(0); // fragile
-        final int keyCount = leftKeys.size();
-        final List<Integer> args = ImmutableIntList.range(0, keyCount);
-        LogicalAggregate aggregate =
-            LogicalAggregate.create(seek, false, ImmutableBitSet.of(), null,
-                ImmutableList.of(
-                    AggregateCall.create(SqlStdOperatorTable.COUNT, false,
-                        ImmutableList.<Integer>of(), -1, longType, null),
-                    AggregateCall.create(SqlStdOperatorTable.COUNT, false,
-                        args, -1, longType, null)));
-        LogicalJoin join =
-            LogicalJoin.create(bb.root, aggregate, rexBuilder.makeLiteral(true),
-                ImmutableSet.<CorrelationId>of(), JoinRelType.INNER);
-        bb.setRoot(join, false);
-      }
-      RexNode rex =
-          bb.register(converted.left,
-              outerJoin ? JoinRelType.LEFT : JoinRelType.INNER, leftKeys);
-
-      subQuery.expr = translateIn(subQuery, bb.root, rex);
-      if (isNotIn) {
-        subQuery.expr =
-            rexBuilder.makeCall(SqlStdOperatorTable.NOT, subQuery.expr);
-      }
-      return;
-
-    case EXISTS:
-      // "select from emp where exists (select a from T)"
-      //
-      // is converted to the following if the subquery is correlated:
-      //
-      // "select from emp left outer join (select AGG_TRUE() as indicator
-      // from T group by corr_var) q where q.indicator is true"
-      //
-      // If there is no correlation, the expression is replaced with a
-      // boolean indicating whether the subquery returned 0 or >= 1 row.
-      call = (SqlBasicCall) subQuery.node;
-      query = call.operand(0);
-      if (!expand) {
-        return;
-      }
-      converted = convertExists(query, RelOptUtil.SubqueryType.EXISTS,
-          subQuery.logic, true, null);
-      assert !converted.right;
-      if (convertNonCorrelatedSubQuery(subQuery, bb, converted.left, true)) {
-        return;
-      }
-      subQuery.expr = bb.register(converted.left, JoinRelType.LEFT);
-      return;
-
-    case SCALAR_QUERY:
-      // Convert the subquery.  If it's non-correlated, convert it
-      // to a constant expression.
-      if (!expand) {
-        return;
-      }
-      call = (SqlBasicCall) subQuery.node;
-      query = call.operand(0);
-      converted = convertExists(query, RelOptUtil.SubqueryType.SCALAR,
-          subQuery.logic, true, null);
-      assert !converted.right;
-      if (convertNonCorrelatedSubQuery(subQuery, bb, converted.left, false)) {
-        return;
-      }
-      rel = convertToSingleValueSubq(query, converted.left);
-      subQuery.expr = bb.register(rel, JoinRelType.LEFT);
-      return;
-
-    case SELECT:
-      // This is used when converting multiset queries:
-      //
-      // select * from unnest(select multiset[deptno] from emps);
-      //
-      converted = convertExists(subQuery.node, RelOptUtil.SubqueryType.SCALAR,
-          subQuery.logic, true, null);
-      assert !converted.right;
-      subQuery.expr = bb.register(converted.left, JoinRelType.LEFT);
-      return;
-
-    default:
-      throw Util.newInternal("unexpected kind of subquery :" + subQuery.node);
+    private static boolean isStream(SqlNode query) {
+        return query instanceof SqlSelect && ((SqlSelect) query).isKeywordPresent(SqlSelectKeyword.STREAM);
     }
-  }
-
-  private RexNode translateIn(SubQuery subQuery, RelNode root,
-      final RexNode rex) {
-    switch (subQuery.logic) {
-    case TRUE:
-      return rexBuilder.makeLiteral(true);
-
-    case UNKNOWN_AS_FALSE:
-      assert rex instanceof RexRangeRef;
-      final int fieldCount = rex.getType().getFieldCount();
-      RexNode rexNode = rexBuilder.makeFieldAccess(rex, fieldCount - 1);
-      rexNode = rexBuilder.makeCall(SqlStdOperatorTable.IS_TRUE, rexNode);
-
-      // Then append the IS NOT NULL(leftKeysForIn).
-      //
-      // RexRangeRef contains the following fields:
-      //   leftKeysForIn,
-      //   rightKeysForIn (the original subquery select list),
-      //   nullIndicator
-      //
-      // The first two lists contain the same number of fields.
-      final int k = (fieldCount - 1) / 2;
-      for (int i = 0; i < k; i++) {
-        rexNode =
-            rexBuilder.makeCall(
-                SqlStdOperatorTable.AND,
-                rexNode,
-                rexBuilder.makeCall(
-                    SqlStdOperatorTable.IS_NOT_NULL,
-                    rexBuilder.makeFieldAccess(rex, i)));
-      }
-      return rexNode;
-
-    case TRUE_FALSE_UNKNOWN:
-    case UNKNOWN_AS_TRUE:
-      // select e.deptno,
-      //   case
-      //   when ct.c = 0 then false
-      //   when dt.i is not null then true
-      //   when e.deptno is null then null
-      //   when ct.ck < ct.c then null
-      //   else false
-      //   end
-      // from e
-      // cross join (select count(*) as c, count(deptno) as ck from v) as ct
-      // left join (select distinct deptno, true as i from v) as dt
-      //   on e.deptno = dt.deptno
-      final Join join = (Join) root;
-      final Project left = (Project) join.getLeft();
-      final RelNode leftLeft = ((Join) left.getInput()).getLeft();
-      final int leftLeftCount = leftLeft.getRowType().getFieldCount();
-      final RelDataType nullableBooleanType =
-          typeFactory.createTypeWithNullability(
-              typeFactory.createSqlType(SqlTypeName.BOOLEAN), true);
-      final RelDataType longType =
-          typeFactory.createSqlType(SqlTypeName.BIGINT);
-      final RexNode cRef = rexBuilder.makeInputRef(root, leftLeftCount);
-      final RexNode ckRef = rexBuilder.makeInputRef(root, leftLeftCount + 1);
-      final RexNode iRef =
-          rexBuilder.makeInputRef(root, root.getRowType().getFieldCount() - 1);
-
-      final RexLiteral zero =
-          rexBuilder.makeExactLiteral(BigDecimal.ZERO, longType);
-      final RexLiteral trueLiteral = rexBuilder.makeLiteral(true);
-      final RexLiteral falseLiteral = rexBuilder.makeLiteral(false);
-      final RexNode unknownLiteral =
-          rexBuilder.makeNullLiteral(SqlTypeName.BOOLEAN);
-
-      final ImmutableList.Builder<RexNode> args = ImmutableList.builder();
-      args.add(rexBuilder.makeCall(SqlStdOperatorTable.EQUALS, cRef, zero),
-          falseLiteral,
-          rexBuilder.makeCall(SqlStdOperatorTable.IS_NOT_NULL, iRef),
-          trueLiteral);
-      final JoinInfo joinInfo = join.analyzeCondition();
-      for (int leftKey : joinInfo.leftKeys) {
-        final RexNode kRef = rexBuilder.makeInputRef(root, leftKey);
-        args.add(rexBuilder.makeCall(SqlStdOperatorTable.IS_NULL, kRef),
-            unknownLiteral);
-      }
-      args.add(rexBuilder.makeCall(SqlStdOperatorTable.LESS_THAN, ckRef, cRef),
-          unknownLiteral,
-          falseLiteral);
-
-      return rexBuilder.makeCall(
-          nullableBooleanType,
-          SqlStdOperatorTable.CASE,
-          args.build());
-
-    default:
-      throw new AssertionError(subQuery.logic);
-    }
-  }
 
-  private static boolean containsNullLiteral(SqlNodeList valueList) {
-    for (SqlNode node : valueList.getList()) {
-      if (node instanceof SqlLiteral) {
-        SqlLiteral lit = (SqlLiteral) node;
-        if (lit.getValue() == null) {
-          return true;
+    public static boolean isOrdered(SqlNode query) {
+        switch (query.getKind()) {
+        case SELECT:
+            return ((SqlSelect) query).getOrderList() != null && ((SqlSelect) query).getOrderList().size() > 0;
+        case WITH:
+            return isOrdered(((SqlWith) query).body);
+        case ORDER_BY:
+            return ((SqlOrderBy) query).orderList.size() > 0;
+        default:
+            return false;
         }
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Determines if a subquery is non-correlated and if so, converts it to a
-   * constant.
-   *
-   * @param subQuery  the call that references the subquery
-   * @param bb        blackboard used to convert the subquery
-   * @param converted RelNode tree corresponding to the subquery
-   * @param isExists  true if the subquery is part of an EXISTS expression
-   * @return if the subquery can be converted to a constant
-   */
-  private boolean convertNonCorrelatedSubQuery(
-      SubQuery subQuery,
-      Blackboard bb,
-      RelNode converted,
-      boolean isExists) {
-    SqlCall call = (SqlBasicCall) subQuery.node;
-    if (subqueryConverter.canConvertSubquery()
-        && isSubQueryNonCorrelated(converted, bb)) {
-      // First check if the subquery has already been converted
-      // because it's a nested subquery.  If so, don't re-evaluate
-      // it again.
-      RexNode constExpr = mapConvertedNonCorrSubqs.get(call);
-      if (constExpr == null) {
-        constExpr =
-            subqueryConverter.convertSubquery(
-                call,
-                this,
-                isExists,
-                isExplain);
-      }
-      if (constExpr != null) {
-        subQuery.expr = constExpr;
-        mapConvertedNonCorrSubqs.put(call, constExpr);
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Converts the RelNode tree for a select statement to a select that
-   * produces a single value.
-   *
-   * @param query the query
-   * @param plan   the original RelNode tree corresponding to the statement
-   * @return the converted RelNode tree
-   */
-  public RelNode convertToSingleValueSubq(
-      SqlNode query,
-      RelNode plan) {
-    // Check whether query is guaranteed to produce a single value.
-    if (query instanceof SqlSelect) {
-      SqlSelect select = (SqlSelect) query;
-      SqlNodeList selectList = select.getSelectList();
-      SqlNodeList groupList = select.getGroup();
-
-      if ((selectList.size() == 1)
-          && ((groupList == null) || (groupList.size() == 0))) {
-        SqlNode selectExpr = selectList.get(0);
-        if (selectExpr instanceof SqlCall) {
-          SqlCall selectExprCall = (SqlCall) selectExpr;
-          if (Util.isSingleValue(selectExprCall)) {
-            return plan;
-          }
-        }
-
-        // If there is a limit with 0 or 1,
-        // it is ensured to produce a single value
-        if (select.getFetch() != null
-            && select.getFetch() instanceof SqlNumericLiteral) {
-          SqlNumericLiteral limitNum = (SqlNumericLiteral) select.getFetch();
-          if (((BigDecimal) limitNum.getValue()).intValue() < 2) {
-            return plan;
-          }
-        }
-      }
-    } else if (query instanceof SqlCall) {
-      // If the query is (values ...),
-      // it is necessary to look into the operands to determine
-      // whether SingleValueAgg is necessary
-      SqlCall exprCall = (SqlCall) query;
-      if (exprCall.getOperator()
-          instanceof SqlValuesOperator
-              && Util.isSingleValue(exprCall)) {
-        return plan;
-      }
     }
 
-    // If not, project SingleValueAgg
-    return RelOptUtil.createSingleValueAggRel(
-        cluster,
-        plan);
-  }
-
-  /**
-   * Converts "x IN (1, 2, ...)" to "x=1 OR x=2 OR ...".
-   *
-   * @param leftKeys   LHS
-   * @param valuesList RHS
-   * @param isNotIn    is this a NOT IN operator
-   * @return converted expression
-   */
-  private RexNode convertInToOr(
-      final Blackboard bb,
-      final List<RexNode> leftKeys,
-      SqlNodeList valuesList,
-      boolean isNotIn) {
-    final List<RexNode> comparisons = new ArrayList<>();
-    for (SqlNode rightVals : valuesList) {
-      RexNode rexComparison;
-      if (leftKeys.size() == 1) {
-        rexComparison =
-            rexBuilder.makeCall(
-                SqlStdOperatorTable.EQUALS,
-                leftKeys.get(0),
-                rexBuilder.ensureType(leftKeys.get(0).getType(),
-                    bb.convertExpression(rightVals), true));
-      } else {
-        assert rightVals instanceof SqlCall;
-        final SqlBasicCall call = (SqlBasicCall) rightVals;
-        assert (call.getOperator() instanceof SqlRowOperator)
-            && call.operandCount() == leftKeys.size();
-        rexComparison =
-            RexUtil.composeConjunction(
-                rexBuilder,
-                Iterables.transform(
-                    Pair.zip(leftKeys, call.getOperandList()),
-                    new Function<Pair<RexNode, SqlNode>, RexNode>() {
-                      public RexNode apply(Pair<RexNode, SqlNode> pair) {
-                        return rexBuilder.makeCall(SqlStdOperatorTable.EQUALS,
-                            pair.left,
-                            rexBuilder.ensureType(pair.left.getType(),
-                                bb.convertExpression(pair.right), true));
-                      }
-                    }),
-                false);
-      }
-      comparisons.add(rexComparison);
+    private RelCollation requiredCollation(RelNode r) {
+        if (r instanceof Sort) {
+            return ((Sort) r).collation;
+        }
+        if (r instanceof Project) {
+            return requiredCollation(((Project) r).getInput());
+        }
+        if (r instanceof Delta) {
+            return requiredCollation(((Delta) r).getInput());
+        }
+        throw new AssertionError();
     }
 
-    RexNode result =
-        RexUtil.composeDisjunction(rexBuilder, comparisons, true);
-    assert result != null;
-
-    if (isNotIn) {
-      result =
-          rexBuilder.makeCall(
-              SqlStdOperatorTable.NOT,
-              result);
+    /**
+     * Converts a SELECT statement's parse tree into a relational expression.
+     */
+    public RelNode convertSelect(SqlSelect select, boolean top) {
+        final SqlValidatorScope selectScope = validator.getWhereScope(select);
+        final Blackboard bb = createBlackboard(selectScope, null, top);
+        convertSelectImpl(bb, select);
+        return bb.root;
     }
 
-    return result;
-  }
-
-  /**
-   * Gets the list size threshold under which {@link #convertInToOr} is used.
-   * Lists of this size or greater will instead be converted to use a join
-   * against an inline table
-   * ({@link org.apache.calcite.rel.logical.LogicalValues}) rather than a
-   * predicate. A threshold of 0 forces usage of an inline table in all cases; a
-   * threshold of Integer.MAX_VALUE forces usage of OR in all cases
-   *
-   * @return threshold, default {@link #IN_SUBQUERY_THRESHOLD}
-   */
-  protected int getInSubqueryThreshold() {
-    /* OVERRIDE POINT */
-    return Integer.MAX_VALUE;
-  }
-
-  /**
-   * Converts an EXISTS or IN predicate into a join. For EXISTS, the subquery
-   * produces an indicator variable, and the result is a relational expression
-   * which outer joins that indicator to the original query. After performing
-   * the outer join, the condition will be TRUE if the EXISTS condition holds,
-   * NULL otherwise.
-   *
-   * @param seek           A query, for example 'select * from emp' or
-   *                       'values (1,2,3)' or '('Foo', 34)'.
-   * @param subqueryType   Whether sub-query is IN, EXISTS or scalar
-   * @param logic Whether the answer needs to be in full 3-valued logic (TRUE,
-   *     FALSE, UNKNOWN) will be required, or whether we can accept an
-   *     approximation (say representing UNKNOWN as FALSE)
-   * @param needsOuterJoin Whether an outer join is needed
-   * @return join expression
-   * @pre extraExpr == null || extraName != null
-   */
-  private Pair<RelNode, Boolean> convertExists(
-      SqlNode seek,
-      RelOptUtil.SubqueryType subqueryType,
-      RelOptUtil.Logic logic,
-      boolean needsOuterJoin,
-      RelDataType targetDataType) {
-    final SqlValidatorScope seekScope =
-        (seek instanceof SqlSelect)
-            ? validator.getSelectScope((SqlSelect) seek)
-            : null;
-    final Blackboard seekBb = createBlackboard(seekScope, null, false);
-    RelNode seekRel = convertQueryOrInList(seekBb, seek, targetDataType);
-
-    return RelOptUtil.createExistsPlan(seekRel, subqueryType, logic,
-        needsOuterJoin);
-  }
-
-  private RelNode convertQueryOrInList(
-      Blackboard bb,
-      SqlNode seek,
-      RelDataType targetRowType) {
-    // NOTE: Once we start accepting single-row queries as row constructors,
-    // there will be an ambiguity here for a case like X IN ((SELECT Y FROM
-    // Z)).  The SQL standard resolves the ambiguity by saying that a lone
-    // select should be interpreted as a table expression, not a row
-    // expression.  The semantic difference is that a table expression can
-    // return multiple rows.
-    if (seek instanceof SqlNodeList) {
-      return convertRowValues(
-          bb,
-          seek,
-          ((SqlNodeList) seek).getList(),
-          false,
-          targetRowType);
-    } else {
-      return convertQueryRecursive(seek, false, null).project();
-    }
-  }
-
-  private RelNode convertRowValues(
-      Blackboard bb,
-      SqlNode rowList,
-      Collection<SqlNode> rows,
-      boolean allowLiteralsOnly,
-      RelDataType targetRowType) {
-    // NOTE jvs 30-Apr-2006: We combine all rows consisting entirely of
-    // literals into a single LogicalValues; this gives the optimizer a smaller
-    // input tree.  For everything else (computed expressions, row
-    // subqueries), we union each row in as a projection on top of a
-    // LogicalOneRow.
-
-    final ImmutableList.Builder<ImmutableList<RexLiteral>> tupleList =
-        ImmutableList.builder();
-    final RelDataType rowType;
-    if (targetRowType != null) {
-      rowType = targetRowType;
-    } else {
-      rowType =
-          SqlTypeUtil.promoteToRowType(
-              typeFactory,
-              validator.getValidatedNodeType(rowList),
-              null);
+    /**
+     * Factory method for creating translation workspace.
+     */
+    protected Blackboard createBlackboard(SqlValidatorScope scope, Map<String, RexNode> nameToNodeMap, boolean top) {
+        return new Blackboard(scope, nameToNodeMap, top);
     }
 
-    final List<RelNode> unionInputs = new ArrayList<>();
-    for (SqlNode node : rows) {
-      SqlBasicCall call;
-      if (isRowConstructor(node)) {
-        call = (SqlBasicCall) node;
-        ImmutableList.Builder<RexLiteral> tuple = ImmutableList.builder();
-        for (Ord<SqlNode> operand : Ord.zip(call.operands)) {
-          RexLiteral rexLiteral =
-              convertLiteralInValuesList(
-                  operand.e,
-                  bb,
-                  rowType,
-                  operand.i);
-          if ((rexLiteral == null) && allowLiteralsOnly) {
-            return null;
-          }
-          if ((rexLiteral == null) || !shouldCreateValuesRel) {
-            // fallback to convertRowConstructor
-            tuple = null;
-            break;
-          }
-          tuple.add(rexLiteral);
-        }
-        if (tuple != null) {
-          tupleList.add(tuple.build());
-          continue;
-        }
-      } else {
-        RexLiteral rexLiteral =
-            convertLiteralInValuesList(
-                node,
-                bb,
-                rowType,
-                0);
-        if ((rexLiteral != null) && shouldCreateValuesRel) {
-          tupleList.add(ImmutableList.of(rexLiteral));
-          continue;
+    /**
+     * Implementation of {@link #convertSelect(SqlSelect, boolean)};
+     * derived class may override.
+     */
+    protected void convertSelectImpl(final Blackboard bb, SqlSelect select) {
+        convertFrom(bb, select.getFrom());
+        convertWhere(bb, select.getWhere());
+
+        final List<SqlNode> orderExprList = new ArrayList<>();
+        final List<RelFieldCollation> collationList = new ArrayList<>();
+        gatherOrderExprs(bb, select, select.getOrderList(), orderExprList, collationList);
+        final RelCollation collation = cluster.traitSet().canonize(RelCollations.of(collationList));
+
+        if (validator.isAggregate(select)) {
+            convertAgg(bb, select, orderExprList);
         } else {
-          if ((rexLiteral == null) && allowLiteralsOnly) {
-            return null;
-          }
+            convertSelectList(bb, select, orderExprList);
         }
 
-        // convert "1" to "row(1)"
-        call =
-            (SqlBasicCall) SqlStdOperatorTable.ROW.createCall(
-                SqlParserPos.ZERO,
-                node);
-      }
-      unionInputs.add(convertRowConstructor(bb, call));
-    }
-    LogicalValues values =
-        LogicalValues.create(cluster, rowType, tupleList.build());
-    RelNode resultRel;
-    if (unionInputs.isEmpty()) {
-      resultRel = values;
-    } else {
-      if (!values.getTuples().isEmpty()) {
-        unionInputs.add(values);
-      }
-      resultRel = LogicalUnion.create(unionInputs, true);
-    }
-    leaves.add(resultRel);
-    return resultRel;
-  }
-
-  private RexLiteral convertLiteralInValuesList(
-      SqlNode sqlNode,
-      Blackboard bb,
-      RelDataType rowType,
-      int iField) {
-    if (!(sqlNode instanceof SqlLiteral)) {
-      return null;
-    }
-    RelDataTypeField field = rowType.getFieldList().get(iField);
-    RelDataType type = field.getType();
-    if (type.isStruct()) {
-      // null literals for weird stuff like UDT's need
-      // special handling during type flattening, so
-      // don't use LogicalValues for those
-      return null;
+        if (select.isDistinct()) {
+            distinctify(bb, true);
+        }
+        convertOrder(select, bb, collation, orderExprList, select.getOffset(), select.getFetch());
+        bb.setRoot(bb.root, true);
     }
 
-    RexNode literalExpr =
-        exprConverter.convertLiteral(
-            bb,
-            (SqlLiteral) sqlNode);
+    /**
+     * Having translated 'SELECT ... FROM ... [GROUP BY ...] [HAVING ...]', adds
+     * a relational expression to make the results unique.
+     *
+     * <p>If the SELECT clause contains duplicate expressions, adds
+     * {@link org.apache.calcite.rel.logical.LogicalProject}s so that we are
+     * grouping on the minimal set of keys. The performance gain isn't huge, but
+     * it is difficult to detect these duplicate expressions later.
+     *
+     * @param bb               Blackboard
+     * @param checkForDupExprs Check for duplicate expressions
+     */
+    private void distinctify(Blackboard bb, boolean checkForDupExprs) {
+        // Look for duplicate expressions in the project.
+        // Say we have 'select x, y, x, z'.
+        // Then dups will be {[2, 0]}
+        // and oldToNew will be {[0, 0], [1, 1], [2, 0], [3, 2]}
+        RelNode rel = bb.root;
+        if (checkForDupExprs && (rel instanceof LogicalProject)) {
+            LogicalProject project = (LogicalProject) rel;
+            final List<RexNode> projectExprs = project.getProjects();
+            final List<Integer> origins = new ArrayList<>();
+            int dupCount = 0;
+            for (int i = 0; i < projectExprs.size(); i++) {
+                int x = findExpr(projectExprs.get(i), projectExprs, i);
+                if (x >= 0) {
+                    origins.add(x);
+                    ++dupCount;
+                } else {
+                    origins.add(i);
+                }
+            }
+            if (dupCount == 0) {
+                distinctify(bb, false);
+                return;
+            }
 
-    if (!(literalExpr instanceof RexLiteral)) {
-      assert literalExpr.isA(SqlKind.CAST);
-      RexNode child = ((RexCall) literalExpr).getOperands().get(0);
-      assert RexLiteral.isNullLiteral(child);
+            final Map<Integer, Integer> squished = Maps.newHashMap();
+            final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
+            final List<Pair<RexNode, String>> newProjects = Lists.newArrayList();
+            for (int i = 0; i < fields.size(); i++) {
+                if (origins.get(i) == i) {
+                    squished.put(i, newProjects.size());
+                    newProjects.add(RexInputRef.of2(i, fields));
+                }
+            }
+            rel = LogicalProject.create(rel, Pair.left(newProjects), Pair.right(newProjects));
+            bb.root = rel;
+            distinctify(bb, false);
+            rel = bb.root;
+
+            // Create the expressions to reverse the mapping.
+            // Project($0, $1, $0, $2).
+            final List<Pair<RexNode, String>> undoProjects = Lists.newArrayList();
+            for (int i = 0; i < fields.size(); i++) {
+                final int origin = origins.get(i);
+                RelDataTypeField field = fields.get(i);
+                undoProjects.add(Pair.of((RexNode) new RexInputRef(squished.get(origin), field.getType()), field.getName()));
+            }
 
-      // NOTE jvs 22-Nov-2006:  we preserve type info
-      // in LogicalValues digest, so it's OK to lose it here
-      return (RexLiteral) child;
-    }
+            rel = LogicalProject.create(rel, Pair.left(undoProjects), Pair.right(undoProjects));
+            bb.setRoot(rel, false);
 
-    RexLiteral literal = (RexLiteral) literalExpr;
+            return;
+        }
 
-    Comparable value = literal.getValue();
+        // Usual case: all of the expressions in the SELECT clause are
+        // different.
+        final ImmutableBitSet groupSet = ImmutableBitSet.range(rel.getRowType().getFieldCount());
+        rel = createAggregate(bb, false, groupSet, ImmutableList.of(groupSet), ImmutableList.<AggregateCall> of());
 
-    if (SqlTypeUtil.isExactNumeric(type) && SqlTypeUtil.hasScale(type)) {
-      BigDecimal roundedValue =
-          NumberUtil.rescaleBigDecimal(
-              (BigDecimal) value,
-              type.getScale());
-      return rexBuilder.makeExactLiteral(
-          roundedValue,
-          type);
+        bb.setRoot(rel, false);
     }
 
-    if ((value instanceof NlsString)
-        && (type.getSqlTypeName() == SqlTypeName.CHAR)) {
-      // pad fixed character type
-      NlsString unpadded = (NlsString) value;
-      return rexBuilder.makeCharLiteral(
-          new NlsString(
-              Spaces.padRight(unpadded.getValue(), type.getPrecision()),
-              unpadded.getCharsetName(),
-              unpadded.getCollation()));
+    private int findExpr(RexNode seek, List<RexNode> exprs, int count) {
+        for (int i = 0; i < count; i++) {
+            RexNode expr = exprs.get(i);
+            if (expr.toString().equals(seek.toString())) {
+                return i;
+            }
+        }
+        return -1;
     }
-    return literal;
-  }
 
-  private boolean isRowConstructor(SqlNode node) {
-    if (!(node.getKind() == SqlKind.ROW)) {
-      return false;
-    }
-    SqlCall call = (SqlCall) node;
-    return call.getOperator().getName().equalsIgnoreCase("row");
-  }
-
-  /**
-   * Builds a list of all <code>IN</code> or <code>EXISTS</code> operators
-   * inside SQL parse tree. Does not traverse inside queries.
-   *
-   * @param bb                           blackboard
-   * @param node                         the SQL parse tree
-   * @param logic Whether the answer needs to be in full 3-valued logic (TRUE,
-   *              FALSE, UNKNOWN) will be required, or whether we can accept
-   *              an approximation (say representing UNKNOWN as FALSE)
-   * @param registerOnlyScalarSubqueries if set to true and the parse tree
-   *                                     corresponds to a variation of a select
-   *                                     node, only register it if it's a scalar
-   *                                     subquery
-   */
-  private void findSubqueries(
-      Blackboard bb,
-      SqlNode node,
-      RelOptUtil.Logic logic,
-      boolean registerOnlyScalarSubqueries) {
-    final SqlKind kind = node.getKind();
-    switch (kind) {
-    case EXISTS:
-    case SELECT:
-    case MULTISET_QUERY_CONSTRUCTOR:
-    case MULTISET_VALUE_CONSTRUCTOR:
-    case ARRAY_QUERY_CONSTRUCTOR:
-    case CURSOR:
-    case SCALAR_QUERY:
-      if (!registerOnlyScalarSubqueries
-          || (kind == SqlKind.SCALAR_QUERY)) {
-        bb.registerSubquery(node, RelOptUtil.Logic.TRUE_FALSE);
-      }
-      return;
-    case IN:
-      if (((SqlCall) node).getOperator() == SqlStdOperatorTable.NOT_IN) {
-        logic = logic.negate();
-      }
-      break;
-    case NOT:
-      logic = logic.negate();
-      break;
-    }
-    if (node instanceof SqlCall) {
-      if (kind == SqlKind.OR
-          || kind == SqlKind.NOT) {
-        // It's always correct to outer join subquery with
-        // containing query; however, when predicates involve Or
-        // or NOT, outer join might be necessary.
-        bb.subqueryNeedsOuterJoin = true;
-      }
-      for (SqlNode operand : ((SqlCall) node).getOperandList()) {
-        if (operand != null) {
-          // In the case of an IN expression, locate scalar
-          // subqueries so we can convert them to constants
-          findSubqueries(
-              bb,
-              operand,
-              logic,
-              kind == SqlKind.IN || registerOnlyScalarSubqueries);
-        }
-      }
-    } else if (node instanceof SqlNodeList) {
-      for (SqlNode child : (SqlNodeList) node) {
-        findSubqueries(
-            bb,
-            child,
-            logic,
-            kind == SqlKind.IN || registerOnlyScalarSubqueries);
-      }
-    }
+    /**
+     * Converts a query's ORDER BY clause, if any.
+     *
+     * @param select        Query
+     * @param bb            Blackboard
+     * @param collation     Collation list
+     * @param orderExprList Method populates this list with orderBy expressions
+     *                      not present in selectList
+     * @param offset        Expression for number of rows to discard before
+     *                      returning first row
+     * @param fetch         Expression for number of rows to fetch
+     */
+    protected void convertOrder(SqlSelect select, Blackboard bb, RelCollation collation, List<SqlNode> orderExprList, SqlNode offset, SqlNode fetch) {
+        if (select.getOrderList() == null || select.getOrderList().getList().isEmpty()) {
+            assert collation.getFieldCollations().isEmpty();
+            if ((offset == null || ((SqlLiteral) offset).bigDecimalValue().equals(BigDecimal.ZERO)) && fetch == null) {
+                return;
+            }
+        }
 
-    // Now that we've located any scalar subqueries inside the IN
-    // expression, register the IN expression itself.  We need to
-    // register the scalar subqueries first so they can be converted
-    // before the IN expression is converted.
-    if (kind == SqlKind.IN) {
-      if (logic == RelOptUtil.Logic.TRUE_FALSE_UNKNOWN
-          && !validator.getValidatedNodeType(node).isNullable()) {
-        logic = RelOptUtil.Logic.UNKNOWN_AS_FALSE;
-      }
-      // TODO: This conversion is only valid in the WHERE clause
-      if (logic == RelOptUtil.Logic.UNKNOWN_AS_FALSE
-          && !bb.subqueryNeedsOuterJoin) {
-        logic = RelOptUtil.Logic.TRUE;
-      }
-      bb.registerSubquery(node, logic);
-    }
-  }
-
-  /**
-   * Converts an expression from {@link SqlNode} to {@link RexNode} format.
-   *
-   * @param node Expression to translate
-   * @return Converted expression
-   */
-  public RexNode convertExpression(
-      SqlNode node) {
-    Map<String, RelDataType> nameToTypeMap = Collections.emptyMap();
-    final ParameterScope scope =
-        new ParameterScope((SqlValidatorImpl) validator, nameToTypeMap);
-    final Blackboard bb = createBlackboard(scope, null, false);
-    return bb.convertExpression(node);
-  }
-
-  /**
-   * Converts an expression from {@link SqlNode} to {@link RexNode} format,
-   * mapping identifier references to predefined expressions.
-   *
-   * @param node          Expression to translate
-   * @param nameToNodeMap map from String to {@link RexNode}; when an
-   *                      {@link SqlIdentifier} is encountered, it is used as a
-   *                      key and translated to the corresponding value from
-   *                      this map
-   * @return Converted expression
-   */
-  public RexNode convertExpression(
-      SqlNode node,
-      Map<String, RexNode> nameToNodeMap) {
-    final Map<String, RelDataType> nameToTypeMap = new HashMap<>();
-    for (Map.Entry<String, RexNode> entry : nameToNodeMap.entrySet()) {
-      nameToTypeMap.put(entry.getKey(), entry.getValue().getType());
-    }
-    final ParameterScope scope =
-        new ParameterScope((SqlValidatorImpl) validator, nameToTypeMap);
-    final Blackboard bb = createBlackboard(scope, nameToNodeMap, false);
-    return bb.convertExpression(node);
-  }
-
-  /**
-   * Converts a non-standard expression.
-   *
-   * <p>This method is an extension-point that derived classes can override. If
-   * this method returns a null result, the normal expression translation
-   * process will proceed. The default implementation always returns null.
-   *
-   * @param node Expression
-   * @param bb   Blackboard
-   * @return null to proceed with the usual expression translation process
-   */
-  protected RexNode convertExtendedExpression(
-      SqlNode node,
-      Blackboard bb) {
-    return null;
-  }
-
-  private RexNode convertOver(Blackboard bb, SqlNode node) {
-    SqlCall call = (SqlCall) node;
-    SqlCall aggCall = call.operand(0);
-    SqlNode windowOrRef = call.operand(1);
-    final SqlWindow window =
-        validator.resolveWindow(windowOrRef, bb.scope, true);
-    // ROW_NUMBER() expects specific kind of framing.
-    if (aggCall.getOperator() == SqlStdOperatorTable.ROW_NUMBER) {
-      window.setLowerBound(SqlWindow.createUnboundedPreceding(SqlParserPos.ZERO));
-      window.setUpperBound(SqlWindow.createCurrentRow(SqlParserPos.ZERO));
-      window.setRows(SqlLiteral.createBoolean(true, SqlParserPos.ZERO));
-    }
-    final SqlNodeList partitionList = window.getPartitionList();
-    final ImmutableList.Builder<RexNode> partitionKeys =
-        ImmutableList.builder();
-    for (SqlNode partition : partitionList) {
-      partitionKeys.add(bb.convertExpression(partition));
-    }
-    RexNode lowerBound = bb.convertExpression(window.getLowerBound());
-    RexNode upperBound = bb.convertExpression(window.getUpperBound());
-    SqlNodeList orderList = window.getOrderList();
-    if ((orderList.size() == 0) && !window.isRows()) {
-      // A logical range requires an ORDER BY clause. Use the implicit
-      // ordering of this relation. There must be one, otherwise it would
-      // have failed validation.
-      orderList = bb.scope.getOrderList();
-      if (orderList == null) {
-        throw new AssertionError(
-            "Relation should have sort key for implicit ORDER BY");
-      }
-    }
-    final ImmutableList.Builder<RexFieldCollation> orderKeys =
-        ImmutableList.builder();
-    final Set<SqlKind> flags = EnumSet.noneOf(SqlKind.class);
-    for (SqlNode order : orderList) {
-      flags.clear();
-      RexNode e = bb.convertSortExpression(order, flags);
-      orderKeys.add(new RexFieldCollation(e, flags));
-    }
-    try {
-      Util.permAssert(bb.window == null, "already in window agg mode");
-      bb.window = window;
-      RexNode rexAgg = exprConverter.convertCall(bb, aggCall);
-      rexAgg =
-          rexBuilder.ensureType(
-              validator.getValidatedNodeType(call), rexAgg, false);
-
-      // Walk over the tree and apply 'over' to all agg functions. This is
-      // necessary because the returned expression is not necessarily a call
-      // to an agg function. For example, AVG(x) becomes SUM(x) / COUNT(x).
-      final RexShuttle visitor =
-          new HistogramShuttle(
-              partitionKeys.build(), orderKeys.build(),
-              RexWindowBound.create(window.getLowerBound(), lowerBound),
-              RexWindowBound.create(window.getUpperBound(), upperBound),
-              window);
-      return rexAgg.accept(visitor);
-    } finally {
-      bb.window = null;
-    }
-  }
-
-  /**
-   * Converts a FROM clause into a relational expression.
-   *
-   * @param bb   Scope within which to resolve identifiers
-   * @param from FROM clause of a query. Examples include:
-   *
-   *             <ul>
-   *             <li>a single table ("SALES.EMP"),
-   *             <li>an aliased table ("EMP AS E"),
-   *             <li>a list of tables ("EMP, DEPT"),
-   *             <li>an ANSI Join expression ("EMP JOIN DEPT ON EMP.DEPTNO =
-   *             DEPT.DEPTNO"),
-   *             <li>a VALUES clause ("VALUES ('Fred', 20)"),
-   *             <li>a query ("(SELECT * FROM EMP WHERE GENDER = 'F')"),
-   *             <li>or any combination of the above.
-   *             </ul>
-   */
-  protected void convertFrom(
-      Blackboard bb,
-      SqlNode from) {
-    final SqlCall call;
-    final SqlNode[] operands;
-    switch (from.getKind()) {
-    case AS:
-      convertFrom(bb, ((SqlCall) from).operand(0));
-      return;
-
-    case WITH_ITEM:
-      convertFrom(bb, ((SqlWithItem) from).query);
-      return;
-
-    case WITH:
-      convertFrom(bb, ((SqlWith) from).body);
-      return;
-
-    case TABLESAMPLE:
-      operands = ((SqlBasicCall) from).getOperands();
-      SqlSampleSpec sampleSpec = SqlLiteral.sampleValue(operands[1]);
-      if (sampleSpec instanceof SqlSampleSpec.SqlSubstitutionSampleSpec) {
-        String sampleName =
-            ((SqlSampleSpec.SqlSubstitutionSampleSpec) sampleSpec)
-                .getName();
-        datasetStack.push(sampleName);
-        convertFrom(bb, operands[0]);
-        datasetStack.pop();
-      } else if (sampleSpec instanceof SqlSampleSpec.SqlTableSampleSpec) {
-        SqlSampleSpec.SqlTableSampleSpec tableSampleSpec =
-            (SqlSampleSpec.SqlTableSampleSpec) sampleSpec;
-        convertFrom(bb, operands[0]);
-        RelOptSamplingParameters params =
-            new RelOptSamplingParameters(
-                tableSampleSpec.isBernoulli(),
-                tableSampleSpec.getSamplePercentage(),
-                tableSampleSpec.isRepeatable(),
-                tableSampleSpec.getRepeatableSeed());
-        bb.setRoot(new Sample(cluster, bb.root, params), false);
-      } else {
-        throw Util.newInternal(
-            "unknown TABLESAMPLE type: " + sampleSpec);
-      }
-      return;
-
-    case IDENTIFIER:
-      final SqlValidatorNamespace fromNamespace =
-          validator.getNamespace(from).resolve();
-      if (fromNamespace.getNode() != null) {
-        convertFrom(bb, fromNamespace.getNode());
-        return;
-      }
-      final String datasetName =
-          datasetStack.isEmpty() ? null : datasetStack.peek();
-      boolean[] usedDataset = {false};
-      RelOptTable table =
-          SqlValidatorUtil.getRelOptTable(
-              fromNamespace,
-              catalogReader,
-              datasetName,
-              usedDataset);
-      final RelNode tableRel;
-      if (shouldConvertTableAccess) {
-        tableRel = toRel(table);
-      } else {
-        tableRel = LogicalTableScan.create(cluster, table);
-      }
-      bb.setRoot(tableRel, true);
-      if (usedDataset[0]) {
-        bb.setDataset(datasetName);
-      }
-      return;
-
-    case JOIN:
-      final SqlJoin join = (SqlJoin) from;
-      final SqlValidatorScope scope = validator.getJoinScope(from);
-      final Blackboard fromBlackboard = createBlackboard(scope, null, false);
-      SqlNode left = join.getLeft();
-      SqlNode right = join.getRight();
-      final boolean isNatural = join.isNatural();
-      final JoinType joinType = join.getJoinType();
-      final SqlValidatorScope leftScope =
-          Util.first(validator.getJoinScope(left),
-              ((DelegatingScope) bb.scope).getParent());
-      final Blackboard leftBlackboard =
-          createBlackboard(leftScope, null, false);
-      final SqlValidatorScope rightScope =
-          Util.first(validator.getJoinScope(right),
-              ((DelegatingScope) bb.scope).getParent());
-      final Blackboard rightBlackboard =
-          createBlackboard(rightScope, null, false);
-      convertFrom(leftBlackboard, left);
-      RelNode leftRel = le

<TRUNCATED>