db-derby-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From rhille...@apache.org
Subject svn commit: r434111 [1/3] - in /db/derby/code/trunk/java: engine/org/apache/derby/impl/sql/compile/ testing/org/apache/derbyTesting/functionTests/master/ testing/org/apache/derbyTesting/functionTests/tests/lang/
Date Wed, 23 Aug 2006 18:14:12 GMT
Author: rhillegas
Date: Wed Aug 23 11:14:11 2006
New Revision: 434111

URL: http://svn.apache.org/viewvc?rev=434111&view=rev
Log:
DERBY-1633: Commit Army's d1633_v3 patches, fixing the regression introduced by DERBY-805 in the behavior of views that involve joins.

Modified:
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/BinaryRelationalOperatorNode.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ColumnReference.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/OptimizerImpl.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/Predicate.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ProjectRestrictNode.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ResultColumnList.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SelectNode.java
    db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SetOperatorNode.java
    db/derby/code/trunk/java/testing/org/apache/derbyTesting/functionTests/master/predicatePushdown.out
    db/derby/code/trunk/java/testing/org/apache/derbyTesting/functionTests/tests/lang/predicatePushdown.sql

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/BinaryRelationalOperatorNode.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/BinaryRelationalOperatorNode.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/BinaryRelationalOperatorNode.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/BinaryRelationalOperatorNode.java Wed Aug 23 11:14:11 2006
@@ -1267,7 +1267,7 @@
 	 * pointing to "T1.j" (or whatever the corresponding column in T1 is).
 	 *
 	 * ASSUMPTION: We should only get to this method if we know that
-	 * at least one operand in the predicate to which this operator belongs
+	 * exactly one operand in the predicate to which this operator belongs
 	 * can and should be mapped to the received childRSN. 
 	 *
      * @param whichSide The operand are we trying to scope (LEFT or RIGHT)
@@ -1277,6 +1277,10 @@
      *  ResultSetNode to which it doesn't apply.
      * @param childRSN The result set node to which we want to create
      *  a scoped predicate.
+     * @param whichRC If not -1 then this tells us which ResultColumn
+     *  in the received childRSN we need to use for the scoped predicate;
+     *  if -1 then the column position of the scoped column reference
+     *  will be stored in this array and passed back to the caller.
      * @return A column reference scoped to the received childRSN, if possible.
      *  If the operand is a ColumnReference that is not supposed to be scoped,
 	 *  we return a _clone_ of the reference--this is necessary because the
@@ -1286,8 +1290,8 @@
 	 *  during optimization.
 	 */
 	public ValueNode getScopedOperand(int whichSide,
-		JBitSet parentRSNsTables, ResultSetNode childRSN)
-		throws StandardException
+		JBitSet parentRSNsTables, ResultSetNode childRSN,
+		int [] whichRC) throws StandardException
 	{
 		ResultColumn rc = null;
 		ColumnReference cr = 
@@ -1295,24 +1299,29 @@
 				? (ColumnReference)leftOperand
 				: (ColumnReference)rightOperand;
 
-		// The first thing we need to do is see if this ColumnReference
-		// is supposed to be scoped for childRSN.  We do that by figuring
-		// out what underlying base table the column reference is pointing
-		// to and then seeing if that base table is included in the list of
-		// table numbers from the parentRSN.
+		/* When we scope a predicate we only scope one side of it--the
+		 * side that is to be evaluated against childRSN.  We figure out
+		 * if "cr" is that side by using table numbers, as seen below.
+		 * This means that for every scoped predicate there will be one
+		 * operand that is scoped and one operand that is not scoped.  
+		 * When we get here for the operand that will not be scoped,
+		 * we'll just return a clone of that operand.  So in the example
+		 * mentioned above, the scoped predicate for the left child of
+		 * X1 would be
+		 *
+		 *   T1.j <scoped> = X2.b <clone> 
+		 *
+		 * That said, the first thing we need to do is see if this
+		 * ColumnReference is supposed to be scoped for childRSN.  We
+		 * do that by figuring out what underlying base table the column
+		 * reference is pointing to and then seeing if that base table
+		 * is included in the list of table numbers from the parentRSN.
+		 */
 		JBitSet crTables = new JBitSet(parentRSNsTables.size());
 		BaseTableNumbersVisitor btnVis =
 			new BaseTableNumbersVisitor(crTables);
 		cr.accept(btnVis);
 
-		// If the column reference doesn't reference any tables,
-		// then there's no point in mapping it to the child result
-		// set; just return a clone of the operand.
-		if (crTables.getFirstSetBit() == -1)
-		{
-			return (ValueNode)cr.getClone();
-		}
-
 		/* If the column reference in question is not intended for
 		 * the received result set node, just leave the operand as
 		 * it is (i.e. return a clone).  In the example mentioned at
@@ -1325,113 +1334,153 @@
 		 * version of that operand.
 		 */
 		if (!parentRSNsTables.contains(crTables))
-		{
-			return (ValueNode)cr.getClone();
-		}
-
-		// If the column reference is already pointing to the
-		// correct table, then there's no need to change it.
-		if ((childRSN.getReferencedTableMap() != null) &&
-			childRSN.getReferencedTableMap().get(cr.getTableNumber()))
-		{
-			return cr;
-		}
+			return (ColumnReference)cr.getClone();
 
 		/* Find the target ResultColumn in the received result set.  At
 		 * this point we know that we do in fact need to scope the column
-		 * reference for childRSN, so go ahead and do it.  We get the
-		 * target column by column position instead of by name because
-		 * it's possible that the name given for the query doesn't match
-		 * the name of the actual column we're looking for.  Ex.
+		 * reference for childRSN, so go ahead and do it.  The way in
+		 * which we get the scope target column differs depending on
+		 * if childRSN corresponds to the left or right child of the
+		 * UNION node.  Before explaining that, though, note that it's
+		 * not good enough to just search for the target column by
+		 * name.  The reason is that it's possible the name provided
+		 * for the column reference to be scoped doesn't match the
+		 * name of the actual underlying column.  Ex.
 		 *
 		 *  select * from
 		 *    (select i,j from t1 union select i,j from t2) X1 (x,y),
 		 *    (select a,b from t3 union select a,b from t4) X2
 		 *  where X1.x = X2.b;
 		 *
-		 * If we searched for "x" in the childRSN "select i,j from t1"
-		 * we wouldn't find it.  So we have to look based on position.
+		 * If we were scoping "X1.x" and we searched for "x" in the
+		 * childRSN "select i,j from t1" we wouldn't find it.
+		 *
+		 * It is similarly incorrect to search for the target column
+		 * by position (DERBY-1633).  This is a bit more subtle, but
+		 * if the child to which we're scoping is a subquery whose RCL
+		 * does not match the column ordering of the RCL for cr's source
+		 * result set, then searching by column position can yield the
+		 * wrong results, as well.  For a detailed example of how this
+		 * can happen, see the fix description attached to DERBY-1633.
+		 * 
+		 * So how do we find the target column, then? As mentioned
+		 * above, the way in which we get the scope target column
+		 * differs depending on if childRSN corresponds to the left
+		 * or right child of the parent UNION node.  And that said,
+		 * we can tell if we're scoping a left child by looking at
+		 * "whichRC" argument: if it is -1 then we know we're scoping
+		 * to the left child of a Union; otherwise we're scoping to
+		 * the right child.
 		 */
-
-		rc = childRSN.getResultColumns().getResultColumn(cr.getColumnNumber());
+		if (whichRC[0] == -1)
+		{
+			/*
+			 * For the left side we start by figuring out what the source
+			 * result set and column position for "cr" are.  Then, since
+			 * a) cr must be pointing to a result column in the parentRSN's
+			 * ResultColumnList,  b) we know that the parent RSN is a
+			 * SetOperatorNode (at least for now, since we only get here
+			 * for Union nodes), and c) SetOpNode's RCLs are built from the
+			 * left child's RCL (see bindResultColumns() in SetOperatorNode),
+			 * we know that if we search the child's RCL for a reference
+			 * whose source result column is the same as cr's source result
+			 * column, we'll find a match.  Once found, the position of the
+			 * matching column w.r.t childRSN's RCL will be stored in the
+			 * whichRC parameter.
+			 */
+
+			// Find the source result set and source column position of cr.
+			int [] sourceColPos = new int[] {-1};
+			ResultSetNode sourceRSN = cr.getSourceResultSet(sourceColPos);
+
+			if (SanityManager.DEBUG)
+			{
+				/* We assumed that if we made it here "cr" was pointing
+				 * to a base table somewhere down the tree.  If that's
+				 * true then sourceRSN won't be null.  Make sure our
+				 * assumption was correct.
+				 */
+				SanityManager.ASSERT(sourceRSN != null,
+					"Failed to find source result set when trying to " +
+					"scope column reference '" + cr.getTableName() +
+					"." + cr.getColumnName());
+			}
+
+			// Now search for the corresponding ResultColumn in childRSN.
+			rc = childRSN.getResultColumns()
+					.getResultColumn(sourceColPos[0], sourceRSN, whichRC);
+		}
+		else
+		{
+			/*
+			 * For the right side the story is slightly different.  If we were
+			 * to search the right child's RCL for a reference whose source
+			 * result column was the same as cr's, we wouldn't find it.  This
+			 * is because cr's source result column comes from the left child's
+			 * RCL and thus the right child doesn't know about it.  That said,
+			 * though, for set operations like UNION, the left and right RCL's
+			 * are correlated by position--i.e. the operation occurs between
+			 * the nth column in the left RCL and the nth column in the right
+			 * RCL.  So given that we will already have found the scope target
+			 * in the left child's RCL at the position in whichRC, we know that
+			 * that scope target for the right child's RCL is simply the
+			 * whichRC'th column in that RCL.
+			 */
+			rc = childRSN.getResultColumns().getResultColumn(whichRC[0]);
+		}
 
 		// rc shouldn't be null; if there was no matching ResultColumn at all,
 		// then we shouldn't have made it this far.
 		if (SanityManager.DEBUG)
 		{
 			SanityManager.ASSERT(rc != null,
-				"Failed to locate result column when trying to " +
+				"Failed to locate scope target result column when trying to " +
 				"scope operand '" + cr.getTableName() + "." +
 				cr.getColumnName() + "'.");
 		}
 
 		/* If the ResultColumn we found has an expression that is a
-		 * ColumnReference, then that column reference has all of the info
-		 * we need, with one exception: the columnNumber.  Depending on our
-		 * depth in the tree, the ResultColumn's ColumnReference could be
-		 * pointing to a base column in the FromBaseTable.  In that case the
-		 * ColumnReference will hold the column position as it is with respect
-		 * to the FromBaseTable.  But when we're scoping a column reference,
-		 * we're scoping it to a ResultSetNode that sits (either directly or
-		 * indirectly) above a ProjectRestrictNode that in turn sits above the
-		 * FromBaseTable. This means that the scoped reference's columnNumber
-		 * needs to be with respect to the PRN that sits above the base table,
-		 * _not_ with respect to the FromBaseTable itself.  This is important
-		 * because column "1" in the PRN might not be column "1" in the
-		 * underlying base table. For example, if we have base table TT with
-		 * four columns (a int, b int, i int, j int) and the PRN above it only
-		 * projects out columns (i,j), then column "1" for the PRN is "i", but
-		 * column "1" for base table TT is "a".  On the flip side, column "3"
-		 * for base table TT is "i", but if we search the PRN's result columns
-		 * (which match the result columns for the ResultSetNode to which
-		 * we're scoping) for column "3", we won't find it.
-		 *
-		 * So what does all of that mean?  It means that if the ResultColumn
-		 * we found has an expression that's a ColumnReference, we can simply
-		 * return that ColumnReference IF we set it's columnNumber correctly.
-		 * Thankfully the column reference we're trying to scope ("cr") came
-		 * from further up the tree and so it knows what the correct column
-		 * position (namely, the position w.r.t the ProjectRestrictNode above
-		 * the FromBaseTable) needs to be.  So that's the column number we
-		 * use.
-		 *
-		 * As a final note, we have to be sure we only set the column
-		 * reference's column number if the reference points to a base table.
-		 * If the reference points to some other ResultSetNode--esp. another
-		 * subquery node--then it (the reference) already holds the correct
-		 * number with respect to that ResultSetNode and we don't change
-		 * it.  The reason is that the reference could end up getting pushed
-		 * down further to that ResultSetNode, in which case we'll do another
-		 * scoping operation and, in order for that to be successful, the
-		 * reference to be scoped has to know what the target column number
-		 * is w.r.t to that ResultSetNode (i.e. it'll be playing the role of
-		 * "cr" as described here).
+		 * ColumnReference, then that column reference has all of the
+		 * info we need.
+		 *
+		 * It is, however, possible that the ResultColumn's expression
+		 * is NOT a ColumnReference.  For example, the expression would
+		 * be a constant expression if childRSN represented something
+		 * like:
+		 *
+		 *   select 1, 1 from t1
+		 *
+		 * In this case the expression does not directly reference a
+		 * column in the underlying result set and is therefore
+		 * "scoped" as far as it can go.  This means that the scoped
+		 * predicate will not necessarily have column references on
+		 * both sides, even though the predicate that we're scoping
+		 * will.  That's not a problem, though, since a predicate with
+		 * a column reference on one side and a non-ColumnReference
+		 * on the other is still valid.
 		 */
+
 		if (rc.getExpression() instanceof ColumnReference)
 		{
-			// Make sure the ColumnReference's columnNumber is correct,
-			// then just return that reference.  Note: it's okay to overwrite
-			// the columnNumber directly because when it eventually makes
-			// it down to the PRN over the FromBaseTable, it will be remapped
-			// for the FromBaseTable and the columnNumber will then be set
-			// correctly.  That remapping is done in the pushOptPredicate()
-			// method of ProjectRestrictNode.
-			ColumnReference cRef = (ColumnReference)rc.getExpression();
-			if (cRef.pointsToBaseTable())
-				cRef.setColumnNumber(cr.getColumnNumber());
+			/* We create a clone of the column reference and mark
+			 * the clone as "scoped" so that we can do the right
+			 * thing when it comes time to remap the predicate;
+			 * see Predicate.remapScopedPred() for more.
+			 */
+			ColumnReference cRef = (ColumnReference)
+				((ColumnReference)rc.getExpression()).getClone();
+			cRef.markAsScoped();
 			return cRef;
 		}
 
-		/* We can get here if the ResultColumn's expression isn't a
-		 * ColumnReference.  For example, the expression would be a
-		 * constant expression if childRSN represented something like:
-		 *
-		 *   select 1, 1 from t1
-		 *
-		 * In this case we just return a clone of the column reference
-		 * because it's scoped as far as we can take it.
+		/* Else just return rc's expression.  This means the scoped
+		 * predicate will have one operand that is _not_ a column
+		 * reference--but that's okay, so long as we account for
+		 * that when pushing/remapping the scoped predicate down
+		 * the query tree (see esp. "isScopedToSourceResultSet()"
+		 * in Predicate.java).
 		 */
-		return (ValueNode)cr.getClone();
+		return rc.getExpression();
 	}
 
 	/**

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ColumnReference.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ColumnReference.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ColumnReference.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ColumnReference.java Wed Aug 23 11:14:11 2006
@@ -81,6 +81,16 @@
 	private int			nestingLevel = -1;
 	private int			sourceLevel = -1;
 
+	/* Whether or not this column reference been scoped for the
+	   sake of predicate pushdown.
+	 */
+	private boolean		scoped;
+
+	/* List of saved remap data if this ColumnReference is scoped
+	   and has been remapped multiple times.
+	 */
+	private java.util.ArrayList remaps;
+
 	/**
 	 * Initializer.
 	 * This one is called by the parser where we could
@@ -105,6 +115,7 @@
 		this.setBeginOffset(((Integer) tokBeginOffset).intValue());
 		this.setEndOffset(((Integer) tokEndOffset).intValue());
 		tableNumber = -1;
+		remaps = null;
 	}
 
 	/**
@@ -119,6 +130,7 @@
 		this.columnName = (String) columnName;
 		this.tableName = (TableName) tableName;
 		tableNumber = -1;
+		remaps = null;
 	}
 
 	/**
@@ -299,6 +311,7 @@
 		nestingLevel = oldCR.getNestingLevel();
 		sourceLevel = oldCR.getSourceLevel();
 		replacesAggregate = oldCR.getGeneratedToReplaceAggregate();
+		scoped = oldCR.isScoped();
 	}
 
 	/**
@@ -642,15 +655,35 @@
 			return;
 		}
 
+		/* Scoped column references are a special case: they can be
+		 * remapped several times (once for every ProjectRestrictNode
+		 * through which the scoped ColumnReference is pushed before
+		 * reaching its target result set) and will be un-remapped
+		 * several times, as well (as the scoped predicate is "pulled"
+		 * back up the query tree to it's original location).  So we
+		 * have to keep track of the "orig" info for every remap
+		 * operation, not just for the most recent one.
+		 */
+		if (scoped && (origSource != null))
+		{
+			if (remaps == null)
+				remaps = new java.util.ArrayList();
+			remaps.add(new RemapInfo(
+				columnNumber, tableNumber, columnName, source));
+		}
+		else
+		{
+			origSource = source;
+			origName = columnName;
+			origColumnNumber = columnNumber;
+			origTableNumber = tableNumber;
+		}
+
 		/* Find the matching ResultColumn */
-		origSource = source;
 		source = getSourceResultColumn();
-		origName = columnName;
 		columnName = source.getName();
-		origColumnNumber = columnNumber;
 		columnNumber = source.getColumnPosition();
 
-		origTableNumber = tableNumber;
 		if (source.getExpression() instanceof ColumnReference)
 		{
 			ColumnReference cr = (ColumnReference) source.getExpression();
@@ -679,12 +712,28 @@
 			// 	"Trying to unremap a ColumnReference that was not remapped.");
 		}
 
-		source = origSource;
-		origSource = null;
-		columnName = origName;
-		origName = null;
-		tableNumber = origTableNumber;
-		columnNumber = origColumnNumber;
+		if ((remaps == null) || (remaps.size() == 0))
+		{
+			source = origSource;
+			origSource = null;
+			columnName = origName;
+			origName = null;
+			tableNumber = origTableNumber;
+			columnNumber = origColumnNumber;
+		}
+		else
+		{
+			// This CR is multiply-remapped, so undo the most
+			// recent (and only the most recent) remap operation.
+			RemapInfo rI = (RemapInfo)remaps.remove(remaps.size() - 1);
+			source = rI.getSource();
+			columnName = rI.getColumnName();
+			tableNumber = rI.getTableNumber();
+			columnNumber = rI.getColumnNumber();
+			rI = null;
+			if (remaps.size() == 0)
+				remaps = null;
+		}
 	}
 
 	/**
@@ -982,50 +1031,142 @@
     } // end of getTypeServices
 
 	/**
-	 * Determine whether or not this ColumnReference's source comes
-	 * from a FromBaseTable (as opposed to some other ResultSetNode).
-	 * We figure this out by walking the ResultColumn/VirtualColumnNode
-	 * chain until we get to last VirtualColumnNode in the chain
-	 * (if there is one), and then seeing what that VCN's source
-	 * result set is.  If there are no VCNs then we check to see
-	 * if the source is pointing to a BaseColumnNode.
-	 *
-	 * This is useful when scoping predicates for pushing; we
-	 * need to know if the predicate's column references are pointing
-	 * directly to base tables so that we can set the scoped references'
-	 * column numbers correctly.
+	 * Find the source result set for this ColumnReference and
+	 * return it.  Also, when the source result set is found,
+	 * return the position (within the source result set's RCL)
+	 * of the column referenced by this ColumnReference.  The
+	 * position is returned vai the colNum parameter.
+	 *
+	 * @param colNum Place to store the position of the column
+	 *  to which this ColumnReference points (position is w.r.t
+	 *  the source result set).
+	 * @return The source result set for this ColumnReference;
+	 *  null if there is no source result set.
 	 */
-	protected boolean pointsToBaseTable() throws StandardException
+	protected ResultSetNode getSourceResultSet(int [] colNum)
+		throws StandardException
 	{
+		if (source == null)
+		{
+			/* this can happen if column reference is pointing to a column
+			 * that is not from a base table.  For example, if we have a
+			 * VALUES clause like
+			 *
+			 *    (values (1, 2), (3, 4)) V1 (i, j)
+			 *
+			 * and then a column reference to VI.i, the column reference
+			 * won't have a source.
+			 */
+			return null;
+		}
+
+		ValueNode rcExpr = null;
 		ResultColumn rc = getSource();
 
-		if (rc == null) {
-		// this can happen if column reference is pointing to a column
-		// that is not from a base table.  For example, if we have a
-		// VALUES clause like
-		//
-		//    (values (1, 2), (3, 4)) V1 (i, j)
-		//
-		// and then a column reference to VI.i, the column reference
-		// won't have a source.
-			return false;
-		}
-
-		// Walk the VirtualColumnNode->ResultColumn chain.
-		VirtualColumnNode vcn = null;
-		ValueNode rcExpr = rc.getExpression();
-		while (rcExpr instanceof VirtualColumnNode) {
-			vcn = (VirtualColumnNode)rcExpr;
-			rc = vcn.getSourceColumn();
+		// Walk the ResultColumn->ColumnReference chain until we
+		// find a ResultColumn whose expression is a VirtualColumnNode.
+
+		rcExpr = rc.getExpression();
+		colNum[0] = getColumnNumber();
+
+		while ((rcExpr != null) && (rcExpr instanceof ColumnReference))
+		{
+			colNum[0] = ((ColumnReference)rcExpr).getColumnNumber();
+			rc = ((ColumnReference)rcExpr).getSource();
+
+			/* If "rc" is redundant then that means it points to another
+			 * ResultColumn that in turn points to the source expression.
+			 * This can happen in cases where "rc" points to a subquery
+			 * that has been flattened into the query above it (flattening
+			 * of subqueries occurs during preprocessing).  In that case
+			 * we want to skip over the redundant rc and find the
+			 * ResultColumn that actually holds the source expression.
+			 */
+			while (rc.isRedundant())
+			{
+				rcExpr = rc.getExpression();
+				if (rcExpr instanceof VirtualColumnNode)
+					rc = ((VirtualColumnNode)rcExpr).getSourceResultColumn();
+				else if (rcExpr instanceof ColumnReference)
+				{
+					colNum[0] = ((ColumnReference)rcExpr).getColumnNumber();
+					rc = ((ColumnReference)rcExpr).getSource();
+				}
+				else
+				{
+					/* If rc isn't pointing to a VirtualColumnNode nor
+					 * to a ColumnReference, then it's not pointing to
+					 * a result set.  It could, for example, be pointing
+					 * to a constant node or to the result of an aggregate
+					 * or function.  Break out of both loops and return
+					 * null since there is no source result set.
+					 */
+					rcExpr = null;
+					break;
+				}
+			}
 			rcExpr = rc.getExpression();
 		}
 
-		// If we've reached the bottom of the chain then see if
-		// the VCN is pointing to a FromBaseTable.
-		if (vcn != null)
-			return (vcn.getSourceResultSet() instanceof FromBaseTable);
+		// If we found a VirtualColumnNode, return the VirtualColumnNode's
+		// sourceResultSet.  The column within that sourceResultSet that
+		// is referenced by this ColumnReference is also returned, via
+		// the colNum parameter, and was set above.
+		if ((rcExpr != null) && (rcExpr instanceof VirtualColumnNode))
+			return ((VirtualColumnNode)rcExpr).getSourceResultSet();
+
+		// If we get here then the ColumnReference doesn't reference
+		// a result set, so return null.
+		colNum[0] = -1;
+		return null;
+	}
+
+	/**
+	 * Mark this column reference as "scoped", which means that it
+	 * was created (as a clone of another ColumnReference) to serve
+	 * as the left or right operand of a scoped predicate.
+	 */
+	protected void markAsScoped()
+	{
+		scoped = true;
+	}
+
+	/**
+	 * Return whether or not this ColumnReference is scoped.
+	 */
+	protected boolean isScoped()
+	{
+		return scoped;
+	}
+
+	/**
+	 * Helper class to keep track of remap data when a ColumnReference
+	 * is remapped multiple times.  This allows the CR to be UN-
+	 * remapped multiple times, as well.
+	 */
+	private class RemapInfo
+	{
+		int colNum;
+		int tableNum;
+		String colName;
+		ResultColumn source;
+
+		RemapInfo(int cNum, int tNum, String cName, ResultColumn rc)
+		{
+			colNum = cNum;
+			tableNum = tNum;
+			colName = cName;
+			source = rc;
+		}
+
+		int getColumnNumber() { return colNum; }
+		int getTableNumber() { return tableNum; }
+		String getColumnName() { return colName; }
+		ResultColumn getSource() { return source; }
 
-		// Else check our source's expression.
-		return (rc.getExpression() instanceof BaseColumnNode);
+		void setColNumber(int cNum) { colNum = cNum; }
+		void setTableNumber(int tNum) { tableNum = tNum; }
+		void setColName(String cName) { colName = cName; }
+		void setSource(ResultColumn rc) { source = rc; }
 	}
 }

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/OptimizerImpl.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/OptimizerImpl.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/OptimizerImpl.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/OptimizerImpl.java Wed Aug 23 11:14:11 2006
@@ -2449,7 +2449,7 @@
 	}
 
 	/**
-	 * Add predicates to this optimizer's predicateList. This method
+	 * Add scoped predicates to this optimizer's predicateList. This method
 	 * is intended for use during the modifyAccessPath() phase of
 	 * compilation, as it allows nodes (esp. SelectNodes) to add to the
 	 * list of predicates available for the final "push" before code
@@ -2465,7 +2465,7 @@
 	 * @param pList List of predicates to add to this OptimizerImpl's
 	 *  own list for pushing.
 	 */
-	protected void addPredicatesToList(PredicateList pList)
+	protected void addScopedPredicatesToList(PredicateList pList)
 		throws StandardException
 	{
 		if ((pList == null) || (pList == predicateList))
@@ -2490,9 +2490,22 @@
 				predicateList.removeOptPredicate(i);
 		}
 
-		// Now transfer all of the received predicates into this
-		// OptimizerImpl's list.
-		pList.transferAllPredicates(predicateList);
+		// Now transfer scoped predicates in the received list to
+		// this OptimizerImpl's list, where appropriate.
+		for (int i = pList.size() - 1; i >= 0; i--)
+		{
+			pred = (Predicate)pList.getOptPredicate(i);
+			if (pred.isScopedToSourceResultSet())
+			{
+				// Clear the scoped predicate's scan flags; they'll be set
+				// as appropriate when they make it to the restrictionList
+				// of the scoped pred's source result set.
+				pred.clearScanFlags();
+				predicateList.addOptPredicate(pred);
+				pList.removeOptPredicate(i);
+			}
+		}
+
 		return;
 	}
 

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/Predicate.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/Predicate.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/Predicate.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/Predicate.java Wed Aug 23 11:14:11 2006
@@ -914,9 +914,12 @@
 		BinaryRelationalOperatorNode opNode =
 			(BinaryRelationalOperatorNode)getAndNode().getLeftOperand();
 
-		// If both sides are column references then this is a join pred.
+		// If both sides are column references AND they point to different
+		// tables, then this is a join pred.
 		return ((opNode.getLeftOperand() instanceof ColumnReference) &&
-			(opNode.getRightOperand() instanceof ColumnReference));
+			(opNode.getRightOperand() instanceof ColumnReference) &&
+			(((ColumnReference)opNode.getLeftOperand()).getTableNumber() !=
+			((ColumnReference)opNode.getRightOperand()).getTableNumber()));
 	}
 
 	/**
@@ -965,12 +968,16 @@
 	 *  ResultSetNode to which they don't apply.
 	 * @param childRSN The result set node for which we want to create
 	 *  a scoped predicate.
+	 * @param whichRC If not -1 then this tells us which ResultColumn
+	 *  in the received childRSN we need to use for the scoped predicate;
+	 *  if -1 then the column position of the scoped column reference
+	 *  will be stored in this array and passed back to the caller.
 	 * @return A new predicate whose operands have been scoped to the
 	 *  received childRSN.
 	 */
 	protected Predicate getPredScopedForResultSet(
-		JBitSet parentRSNsTables, ResultSetNode childRSN)
-		throws StandardException
+		JBitSet parentRSNsTables, ResultSetNode childRSN,
+		int [] whichRC) throws StandardException
 	{
 		// We only deal with binary relational operators here.
 		if (!(getAndNode().getLeftOperand()
@@ -999,11 +1006,13 @@
 				opNode.getScopedOperand(
 					BinaryRelationalOperatorNode.LEFT,
 					parentRSNsTables,
-					childRSN),
+					childRSN,
+					whichRC),
 				opNode.getScopedOperand(
 					BinaryRelationalOperatorNode.RIGHT,
 					parentRSNsTables,
-					childRSN),
+					childRSN,
+					whichRC),
 				getContextManager());
 
 		// Bind the new op node.
@@ -1062,4 +1071,232 @@
 		return scoped;
 	}
 
+	/**
+	 * When remapping a "normal" (i.e. non-scoped) predicate both
+	 * of the predicate's operands are remapped and that's it.
+	 * But when remapping a scoped predicate, things are slightly
+	 * different.  This method handles remapping of scoped predicates.
+	 *
+	 * We know that, for a scoped predicate, exactly one operand has
+	 * been scoped for a specific target result set; the other operand
+	 * is pointing to some other instance of FromTable with which the
+	 * target result set is to be joined (see getScopedOperand() in
+	 * BinaryRelationalOperatorNode.java).  For every level of the
+	 * query through which the scoped predicate is pushed, we have
+	 * to perform a remap operation of the scoped operand.  We do
+	 * *not*, however, remap the non-scoped operand.  The reason
+	 * is that the non-scoped operand is already pointing to the
+	 * result set against which it must be evaluated.  As the scoped
+	 * predicate is pushed down the query tree, the non-scoped
+	 * operand should not change where it's pointing and thus should
+	 * not be remapped.  For example, assume we have a query whose
+	 * tree has the following form:
+	 *
+	 *               SELECT[0] 
+	 *                /     \ 
+	 *              PRN      PRN 
+	 *               |        |
+	 *          SELECT[4]   UNION
+	 *           |           /   \ 
+	 *          PRN     SELECT[1]  SELECT[2] 
+	 *           |         |          | 
+	 *       <FBT:T1>     PRN        PRN 
+	 *                     |          |
+	 *                SELECT[3]  <FromBaseTable:T2> 
+	 *                     |
+	 *                    PRN
+	 *                     |
+	 *             <FromBaseTable:T3>
+	 *
+	 * Assume also that we have some predicate "SELECT[4].i = <UNION>.j".
+	 * If the optimizer decides to push the predicate to the UNION
+	 * node, it (the predicate) will be scoped to the UNION's children,
+	 * yielding something like "SELECT[4].i = SELECT[1].j" for the
+	 * left child and "SELECT[4].i = SELECT[2].j" for the right child.
+	 * These scoped predicates will then be pushed to the PRNs above
+	 * SELECT[3] and T2, respectively.  As part of that pushing
+	 * process a call to PRN.pushOptPredicate() will occur, which
+	 * brings us to this method.  So let's assume we're here for
+	 * the scoped predicate "SELECT[4].i = SELECT[1].j".  Then we want
+	 * to remap the scoped operand, "SELECT[1].j", so that it will
+	 * point to the correct column in "SELECT[3]".  We do NOT, however,
+	 * want to remap the non-scoped operand "SELECT[4].i" because that
+	 * operand is already pointing to the correct result set--namely,
+	 * to a column in SELECT[4].  That non-scoped operand should not
+	 * change regardless of how far down the UNION subtree the scoped
+	 * predicate is pushed.
+	 * 
+	 * If we did try to remap the non-scoped operand, it would end up
+	 * pointing to result sets too low in the tree, which could lead to
+	 * execution-time errors.  So when we remap a scoped predicate, we
+	 * have to make sure we only remap the scoped operand.  That's what
+	 * this method does.
+	 *
+	 * @return True if this predicate is a scoped predicate, in which
+	 *  case we performed a one-sided remap.  False if the predicate is
+	 *  not scoped; the caller can then make the calls to perform a
+	 *  "normal" remap on this predicate.
+	 */
+	protected boolean remapScopedPred()
+	{
+		if (!scoped)
+			return false;
+
+		/* Note: right now the only predicates we scope are those
+		 * which are join predicates and all scoped predicates will
+		 * have the same relational operator as the predicates from
+		 * which they were scoped.  Thus if we get here, we know
+		 * that andNode's leftOperand must be an instance of
+		 * BinaryRelationalOperatorNode (and therefore the following
+		 * cast is safe).
+		 */
+		BinaryRelationalOperatorNode binRelOp =
+			(BinaryRelationalOperatorNode)andNode.getLeftOperand();
+
+		ValueNode operand = null;
+
+		if (SanityManager.DEBUG)
+		{
+			/* If this predicate is scoped then one (and only one) of
+			 * its operands should be scoped.  Note that it's possible
+			 * for an operand to be scoped to a non-ColumnReference
+			 * value; if either operand is not a ColumnReference, then
+			 * that operand must be the scoped operand.
+			 */
+			operand = binRelOp.getLeftOperand();
+			boolean leftIsScoped =
+				!(operand instanceof ColumnReference) ||
+					((ColumnReference)operand).isScoped();
+
+			operand = binRelOp.getRightOperand();
+			boolean rightIsScoped =
+				!(operand instanceof ColumnReference) ||
+					((ColumnReference)operand).isScoped();
+
+			SanityManager.ASSERT(leftIsScoped ^ rightIsScoped,
+				"All scoped predicates should have exactly one scoped " +
+				"operand, but '" + binaryRelOpColRefsToString() +
+				"' has " + (leftIsScoped ? "TWO" : "NONE") + ".");
+		}
+
+		// Find the scoped operand and remap it.
+		operand = binRelOp.getLeftOperand();
+		if ((operand instanceof ColumnReference) &&
+			((ColumnReference)operand).isScoped())
+		{
+			// Left operand is the scoped operand.
+			((ColumnReference)operand).remapColumnReferences();
+		}
+		else
+		{
+			operand = binRelOp.getRightOperand();
+			if ((operand instanceof ColumnReference) &&
+				((ColumnReference)operand).isScoped())
+			{
+				// Right operand is the scoped operand.
+				((ColumnReference)operand).remapColumnReferences();
+			}
+
+			// Else scoped operand is not a ColumnReference, which
+			// means it can't (and doesn't need to) be remapped. So
+			// just fall through and return.
+		}
+
+		return true;
+	}
+
+	/**
+	 * Return true if this predicate is scoped AND the scoped
+	 * operand is a ColumnReference that points to a source result
+	 * set.  If the scoped operand is not a ColumnReference that
+	 * points to a source result set then it must be pointing to
+	 * some kind of expression, such as a literal (ex. 'strlit'),
+	 * an aggregate value (ex. "count(*)"), or the result of a
+	 * function (ex. "sin(i)") or operator (ex. "i+1").
+	 *
+	 * This method is used when pushing predicates to determine how
+	 * far down the query tree a scoped predicate needs to be pushed
+	 * to allow for successful evaluation of the scoped operand.  If
+	 * the scoped operand is not pointing to a source result set
+	 * then it should not be pushed any further down tree.  The reason
+	 * is that evaluation of the expression to which the operand is
+	 * pointing may depend on other values from the current level
+	 * in the tree (ex. "sin(i)" depends on the value of "i", which
+	 * could be a column at the predicate's current level).  If we
+	 * pushed the predicate further down, those values could become
+	 * inaccessible, leading to execution-time errors.
+	 *
+	 * If, on the other hand, the scoped operand *is* pointing to
+	 * a source result set, then we want to push it further down
+	 * the tree until it reaches that result set, which allows
+	 * evaluation of this predicate to occur as close to store as
+	 * possible.  This method doesn't actually do the push, it just
+	 * returns "true" and then the caller can push as appropriate.
+	 */
+	protected boolean isScopedToSourceResultSet()
+		throws StandardException
+	{
+		if (!scoped)
+			return false;
+
+		/* Note: right now the only predicates we scope are those
+		 * which are join predicates and all scoped predicates will
+		 * have the same relational operator as the predicates from
+		 * which they were scoped.  Thus if we get here, we know
+		 * that andNode's leftOperand must be an instance of
+		 * BinaryRelationalOperatorNode (and therefore the following
+		 * cast is safe).
+		 */
+		BinaryRelationalOperatorNode binRelOp =
+			(BinaryRelationalOperatorNode)andNode.getLeftOperand();
+
+		ValueNode operand = binRelOp.getLeftOperand();
+
+		/* If operand isn't a ColumnReference then is must be the
+		 * scoped operand.  This is because both operands have to
+		 * be column references in order for scoping to occur (as
+		 * per pushableToSubqueries()) and only the scoped operand
+		 * can change (esp. can become a non-ColumnReference) as
+		 * part of the scoping process.  And since it's not a
+		 * ColumnReference it can't be "a ColumnReference that
+		 * points to a source result set", so return false.
+		 */
+		if (!(operand instanceof ColumnReference))
+			return false;
+
+		/* If the operand is a ColumnReference and is scoped,
+		 * then see if it is pointing to a ResultColumn whose
+		 * expression is either another a CR or a Virtual
+		 * ColumnNode.  If it is then that operand applies
+		 * to a source result set further down the tree and
+		 * thus we return true.
+		 */
+		ValueNode exp = null;
+		ColumnReference cRef = (ColumnReference)operand;
+		if (cRef.isScoped())
+		{
+			exp = cRef.getSource().getExpression();
+			return ((exp instanceof VirtualColumnNode) ||
+				(exp instanceof ColumnReference));
+		}
+
+		operand = binRelOp.getRightOperand();
+		if (!(operand instanceof ColumnReference))
+			return false;
+
+		cRef = (ColumnReference)operand;
+		if (SanityManager.DEBUG)
+		{
+			// If we got here then the left operand was NOT the scoped
+			// operand; make sure the right one is scoped, then.
+			SanityManager.ASSERT(cRef.isScoped(),
+				"All scoped predicates should have exactly one scoped " +
+				"operand, but '" + binaryRelOpColRefsToString() +
+				"has NONE.");
+		}
+
+		exp = cRef.getSource().getExpression();
+		return ((exp instanceof VirtualColumnNode) ||
+			(exp instanceof ColumnReference));
+	}
 }

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ProjectRestrictNode.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ProjectRestrictNode.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ProjectRestrictNode.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ProjectRestrictNode.java Wed Aug 23 11:14:11 2006
@@ -547,8 +547,17 @@
 		/* Remap all of the ColumnReferences to point to the
 		 * source of the values.
 		 */
-		RemapCRsVisitor rcrv = new RemapCRsVisitor(true);
-		((Predicate) optimizablePredicate).getAndNode().accept(rcrv);
+		Predicate pred = (Predicate)optimizablePredicate;
+
+		/* If the predicate is scoped then the call to "remapScopedPred()"
+		 * will do the necessary remapping for us and will return true;
+		 * otherwise, we'll just do the normal remapping here.
+		 */
+		if (!pred.remapScopedPred())
+		{
+			RemapCRsVisitor rcrv = new RemapCRsVisitor(true);
+			pred.getAndNode().accept(rcrv);
+		}
 
 		return true;
 	}
@@ -613,7 +622,14 @@
 			// Remember that the original child was not Optimizable
 			origChildOptimizable = false;
 
-			childResult = childResult.modifyAccessPaths();
+			/* When we optimized the child we passed in our restriction list
+			 * so that scoped predicates could be pushed further down the
+			 * tree.  We need to do the same when modifying the access
+			 * paths to ensure we generate the same plans the optimizer
+			 * chose.
+			 */
+			childResult = childResult.modifyAccessPaths(restrictionList);
+
 			/* Mark this node as having the truly ... for
 			 * the underlying tree.
 			 */

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ResultColumnList.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ResultColumnList.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ResultColumnList.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/ResultColumnList.java Wed Aug 23 11:14:11 2006
@@ -221,6 +221,52 @@
 	}
 
 	/**
+	 * Take a column position and a ResultSetNode and find the ResultColumn
+	 * in this RCL whose source result set is the same as the received
+	 * RSN and whose column position is the same as the received column
+	 * position.
+	 *
+	 * @param colNum The column position (w.r.t rsn) for which we're searching
+	 * @param rsn The result set node for which we're searching.
+	 * @return The ResultColumn in this RCL whose source is column colNum
+	 *  in result set rsn.  That ResultColumn's position w.r.t to this RCL
+	 *  is also returned via the whichRC parameter.  If no match is found,
+	 *  return null and leave whichRC untouched.
+	 */
+	public ResultColumn getResultColumn(int colNum, ResultSetNode rsn,
+		int [] whichRC) throws StandardException
+	{
+		if (colNum == -1)
+			return null;
+
+		ResultColumn rc = null;
+		ColumnReference colRef = null;
+		int [] crColNum = new int[] { -1 };
+
+		for (int index = size() - 1; index >= 0; index--)
+		{
+			rc = (ResultColumn) elementAt(index);
+			if (!(rc.getExpression() instanceof ColumnReference))
+			{
+				// If the rc's expression isn't a column reference then
+				// it can't be pointing to rsn, so just skip it.
+				continue;
+			}
+
+			colRef = (ColumnReference)rc.getExpression();
+			if ((rsn == colRef.getSourceResultSet(crColNum)) &&
+				(crColNum[0] == colNum))
+			{
+				// Found a match.
+				whichRC[0] = index+1;
+				return rc;
+			}
+		}
+
+		return null;
+	}
+
+	/**
 	 * Get a ResultColumn from a column position (1-based) in the list,
 	 * null if out of range (for order by).
 	 *

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SelectNode.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SelectNode.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SelectNode.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SelectNode.java Wed Aug 23 11:14:11 2006
@@ -1621,11 +1621,10 @@
 			for (int i = sz - 1; i >= 0; i--)
 			{
 				// We can tell if a predicate was pushed into this select
-				// node because it will have been "scoped" for this node;
-				// see Predicate.getScopedPredForResultSet() for more on
-				// what scoping is and how it's done.
+				// node because it will have been "scoped" for this node
+				// or for some result set below this one.
 				pred = (Predicate)predicateList.getOptPredicate(i);
-				if (pred.isScopedForPush())
+				if (pred.isScopedToSourceResultSet())
 				{
 					// If we're pushing the predicate down here, we have to
 					// remove it from the predicate list of the node above
@@ -1652,6 +1651,26 @@
 			}
 		}
 
+		/* When we're done optimizing, any scoped predicates that
+		 * we pushed down the tree should now be sitting again
+		 * in our wherePredicates list.  Put those back in the
+		 * the list from which we received them, to allow them
+		 * to be "pulled" back up to where they came from.
+		 */
+		if (wherePredicates != null)
+		{
+			Predicate pred = null;
+			for (int i = wherePredicates.size() - 1; i >= 0; i--)
+			{
+				pred = (Predicate)wherePredicates.getOptPredicate(i);
+				if (pred.isScopedForPush())
+				{
+					predicateList.addOptPredicate(pred);
+					wherePredicates.removeOptPredicate(pred);
+				}
+			}
+		}
+
 		/* Get the cost */
 		costEstimate = optimizer.getOptimizedCost();
 
@@ -1698,7 +1717,7 @@
 				"modifying access paths.");
 		}
 
-		((OptimizerImpl)optimizer).addPredicatesToList(predList);
+		((OptimizerImpl)optimizer).addScopedPredicatesToList(predList);
 		return modifyAccessPaths();
 	}
 

Modified: db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SetOperatorNode.java
URL: http://svn.apache.org/viewvc/db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SetOperatorNode.java?rev=434111&r1=434110&r2=434111&view=diff
==============================================================================
--- db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SetOperatorNode.java (original)
+++ db/derby/code/trunk/java/engine/org/apache/derby/impl/sql/compile/SetOperatorNode.java Wed Aug 23 11:14:11 2006
@@ -305,33 +305,6 @@
 		if (!canPush)
 			return false;
 
-		BinaryRelationalOperatorNode opNode =
-			(BinaryRelationalOperatorNode)pred.getAndNode().getLeftOperand();
-
-		// Note: we assume we only get here for predicates with col refs on
-		// both sides; if that ever changes, the following cast will need
-		// to be updated accordingly.
-		boolean opWasRemapped = 
-			((ColumnReference)opNode.getLeftOperand()).hasBeenRemapped();
-
-		/* If there is a ProjectRestrictNode directly above this node,
-		 * then the predicate in question may have been remapped to this
-		 * SetOperatorNode before we got here (see pushOptPredicate() in
-		 * ProjectRestrictNode).  If we leave it mapped when we try to
-		 * get scoped predicates for the left and right result sets, the
-		 * underlying column references of the scoped predicates will
-		 * effectively be doubly-mapped (i.e. mapped more than once), which
-		 * can cause problems at code generation time.  So we 1) un-remap
-		 * the predicate here, 2) get the scoped predicates, and then
-		 * 3) remap the predicate again at the end of this method.
-		 */
-		RemapCRsVisitor rcrv = null;
-		if (opWasRemapped)
-		{
-			rcrv = new RemapCRsVisitor(false);
-			pred.getAndNode().accept(rcrv);
-		}
-
 		// Get a list of all of the underlying base tables that this node
 		// references.  We pass this down when scoping so that we can tell
 		// if the operands are actually supposed to be scoped to _this_
@@ -359,6 +332,10 @@
 		 * in the following code does.
 		 */
 
+		// For details on how this whichRC variable is used, see the
+		// comments in BinaryRelationalOperatorNode.getScopedOperand().
+		int [] whichRC = new int[] { -1 };
+
 		// See if we already have a scoped version of the predicate cached,
 		// and if so just use that.
 		Predicate scopedPred = null;
@@ -369,7 +346,7 @@
 		if (scopedPred == null)
 		{
 			scopedPred = pred.getPredScopedForResultSet(
-				tableNums, leftResultSet);
+				tableNums, leftResultSet, whichRC);
 			leftScopedPreds.put(pred, scopedPred);
 		}
 
@@ -384,21 +361,13 @@
 		if (scopedPred == null)
 		{
 			scopedPred = pred.getPredScopedForResultSet(
-				tableNums, rightResultSet);
+				tableNums, rightResultSet, whichRC);
 			rightScopedPreds.put(pred, scopedPred);
 		}
 
 		// Add the scoped predicate to our list for the right child.
 		getRightOptPredicateList().addOptPredicate(scopedPred);
 
-		// Restore the original predicate to the way it was before we got
-		// here--i.e. remap it again if needed.
-		if (opWasRemapped)
-		{
-			rcrv = new RemapCRsVisitor(true);
-			pred.getAndNode().accept(rcrv);
-		}
-
 		// Add the predicate (in its original form) to our list of predicates
 		// that we've pushed during this phase of optimization.  We need to
 		// keep this list of pushed predicates around so that we can do
@@ -453,11 +422,22 @@
 		 * push that predicate elsewhere
 		 */
 		Predicate pred = null;
+		RemapCRsVisitor rcrv = new RemapCRsVisitor(false);
 		for (int i = 0; i < pushedPredicates.size(); i++)
 		{
 			pred = (Predicate)pushedPredicates.getOptPredicate(i);
 			if (pred.isScopedForPush())
+			{
+				/* We don't need to pull the predicate if it's scoped, but
+				 * since scoped predicates are cached between rounds of
+				 * optimization, it's possible that we'll reuse the scoped
+				 * predicate again in a later round.  So to make sure we
+				 * get a "fresh start" in later rounds, we un-remap the
+				 * predicate here.
+				 */
+ 				pred.getAndNode().accept(rcrv);
 				continue;
+			}
 			optimizablePredicates.addOptPredicate(pred);
 		}
 



Mime
View raw message