Partial indexes work again, courtesy of Martijn van Oosterhout.

Note: I didn't force an initdb, figuring that one today was enough.
However, there is a new function in pg_proc.h, and pg_dump won't be
able to dump partial indexes until you add that function.

32 files changed, 469 insertions, 486 deletions

diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml
index abda7fd77fe..d81ce775173 100644
--- a/doc/src/sgml/indices.sgml
+++ b/doc/src/sgml/indices.sgml
@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/indices.sgml,v 1.19 2001/05/30 04:01:11 momjian Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/indices.sgml,v 1.20 2001/07/16 05:06:57 tgl Exp $ -->
 
 <chapter id="indexes">
  <title id="indexes-title">Indexes</title>
@@ -603,22 +603,11 @@ CREATE MEMSTORE ON <replaceable>table</replaceable> COLUMNS <replaceable>cols</r
     </para>
    </note>
 
-   <note>
-    <title>Note</title>
-    <para>
-     Partial indexes are not currently supported by
-     <productname>PostgreSQL</productname>, but they were once supported
-     by its predecessor <productname>Postgres</productname>, and much
-     of the code is still there.  We hope to revive support for this
-     feature someday.
-    </para>
-   </note>
-
    <para>
     A <firstterm>partial index</firstterm>
     is an index built over a subset of a table; the subset is defined by
     a predicate.  <productname>Postgres</productname>
-    supported partial indexes with arbitrary
+    supports partial indexes with arbitrary
     predicates.  I believe IBM's <productname>DB2</productname>
     for AS/400 supports partial indexes
     using single-clause predicates.
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index bc72fb1993a..e5194c255c6 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_index.sgml,v 1.19 2001/05/17 21:50:18 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_index.sgml,v 1.20 2001/07/16 05:06:57 tgl Exp $
 Postgres documentation
 -->
 
@@ -20,13 +20,15 @@ Postgres documentation
  </refnamediv>
  <refsynopsisdiv>
   <refsynopsisdivinfo>
-   <date>1999-07-20</date>
+   <date>2001-07-15</date>
   </refsynopsisdivinfo>
   <synopsis>
 CREATE [ UNIQUE ] INDEX <replaceable class="parameter">index_name</replaceable> ON <replaceable class="parameter">table</replaceable>
-    [ USING <replaceable class="parameter">acc_name</replaceable> ] ( <replaceable class="parameter">column</replaceable> [ <replaceable class="parameter">ops_name</replaceable> ] [, ...] )
+    [ USING <replaceable class="parameter">acc_method</replaceable> ] ( <replaceable class="parameter">column</replaceable> [ <replaceable class="parameter">ops_name</replaceable> ] [, ...] )
+    [ WHERE <replaceable class="parameter">predicate</replaceable> ]
 CREATE [ UNIQUE ] INDEX <replaceable class="parameter">index_name</replaceable> ON <replaceable class="parameter">table</replaceable>
-    [ USING <replaceable class="parameter">acc_name</replaceable> ] ( <replaceable class="parameter">func_name</replaceable>( <replaceable class="parameter">column</replaceable> [, ... ]) [ <replaceable class="parameter">ops_name</replaceable> ] )
+    [ USING <replaceable class="parameter">acc_method</replaceable> ] ( <replaceable class="parameter">func_name</replaceable>( <replaceable class="parameter">column</replaceable> [, ... ]) [ <replaceable class="parameter">ops_name</replaceable> ] )
+    [ WHERE <replaceable class="parameter">predicate</replaceable> ]
   </synopsis>
 
   <refsect2 id="R2-SQL-CREATEINDEX-1">
@@ -71,12 +73,12 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">index_name</replaceable>
      </varlistentry>
 
      <varlistentry>
-      <term><replaceable class="parameter">acc_name</replaceable></term>
+      <term><replaceable class="parameter">acc_method</replaceable></term>
       <listitem>
        <para>
 	The name of the access method to be used for
 	the index. The default access method is BTREE.
-	Postgres provides three access methods for indexes:
+	Postgres provides four access methods for indexes:
 
 	<variablelist>
 	 <varlistentry>
@@ -106,6 +108,15 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">index_name</replaceable>
 	   </para>
 	  </listitem>
 	 </varlistentry>
+
+	 <varlistentry>
+	  <term>GIST</term>
+	  <listitem>
+	   <para>
+	    Generalized Index Search Trees.
+	   </para>
+	  </listitem>
+	 </varlistentry>
 	</variablelist>
        </para>
       </listitem>
@@ -137,6 +148,15 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">index_name</replaceable>
        </para>
       </listitem>
      </varlistentry>
+
+     <varlistentry>
+      <term><replaceable class="parameter">predicate</replaceable></term>
+      <listitem>
+       <para>
+	Defines the constraint expression for a partial index.
+       </para>
+      </listitem>
+     </varlistentry>
     </variablelist>
    </para>
   </refsect2>
@@ -216,7 +236,7 @@ ERROR: Cannot create index: 'index_name' already exists.
   </para>
 
   <para>
-   Postgres provides btree, rtree and hash access methods for
+   Postgres provides btree, rtree, hash, and GiST access methods for
    indexes.  The btree access method is an implementation of
    Lehman-Yao high-concurrency btrees.  The rtree access method
    implements standard rtrees using Guttman's quadratic split algorithm.
@@ -228,6 +248,32 @@ ERROR: Cannot create index: 'index_name' already exists.
   </para>
 
   <para>
+    When the <command>WHERE</command> clause is present, a
+    <firstterm>partial index</firstterm> is created.
+    A partial index is an index that contains entries for only a portion of
+    a table, usually a portion that is somehow more interesting than the
+    rest of the table. For example, if you have a table that contains both
+    billed and unbilled orders where the unbilled orders take up a small
+    fraction of the total table and yet that is an often used section, you
+    can improve performance by creating an index on just that portion.
+  </para>
+
+  <para>
+    The expression used in the <command>WHERE</command> clause may refer
+    only to columns of the underlying table (but it can use all columns,
+    not only the one(s) being indexed).  Currently, the
+    <productname>PostgreSQL</productname> planner can only devise query
+    plans that make use of a partial index when the predicate is built from
+    <command>AND</command> and <command>OR</command> combinations of
+    elements of the form
+    <firstterm>column</firstterm>
+    <firstterm>operator</firstterm>
+    <firstterm>constant</firstterm>.
+    However, more general predicates may still be useful in conjunction
+    with UNIQUE indexes, to enforce uniqueness over a subset of a table.
+  </para>
+
+  <para>
    Use <xref linkend="sql-dropindex" endterm="sql-dropindex-title">
    to remove an index.
   </para>
@@ -278,9 +324,10 @@ ERROR: Cannot create index: 'index_name' already exists.
    </para>
 
    <para>
-    Currently, only the btree access method supports multi-column
+    Currently, only the btree and gist access methods support multi-column
     indexes. Up to 16 keys may be specified by default (this limit
-    can be altered when building Postgres).
+    can be altered when building Postgres).  Only btree currently supports
+    unique indexes.
    </para>
 
   <para>
@@ -307,9 +354,9 @@ ERROR: Cannot create index: 'index_name' already exists.
       The difference between them is that <literal>bigbox_ops</literal>
       scales box coordinates down, to avoid floating-point exceptions from
       doing multiplication, addition, and subtraction on very large
-      floating-point coordinates.  If the field on which your rectangles lie
-      is about 20,000 units square or larger, you should use
-      <literal>bigbox_ops</literal>.
+      floating-point coordinates.  (Note: this was true some time ago,
+      but currently the two operator classes both use floating point
+      and are effectively identical.)
      </para>
     </listitem>
    </itemizedlist>
@@ -319,7 +366,7 @@ ERROR: Cannot create index: 'index_name' already exists.
     The following query shows all defined operator classes:
 
     <programlisting>
-SELECT am.amname AS acc_name,
+SELECT am.amname AS acc_method,
        opc.opcname AS ops_name,
        opr.oprname AS ops_comp
     FROM pg_am am, pg_amop amop,
@@ -327,7 +374,7 @@ SELECT am.amname AS acc_name,
     WHERE amop.amopid = am.oid AND
           amop.amopclaid = opc.oid AND
           amop.amopopr = opr.oid
-    ORDER BY acc_name, ops_name, ops_comp
+    ORDER BY acc_method, ops_name, ops_comp
     </programlisting>
    </para>
   </refsect2>
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index ee1a4b7c31f..7fc54779680 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.111 2001/07/15 22:48:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.112 2001/07/16 05:06:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1100,8 +1100,9 @@ index_register(char *heap,
 	newind->il_info = (IndexInfo *) palloc(sizeof(IndexInfo));
 
 	memcpy(newind->il_info, indexInfo, sizeof(IndexInfo));
-	/* predicate will likely be null anyway, but may as well copy it */
-	newind->il_info->ii_Predicate = copyObject(indexInfo->ii_Predicate);
+	/* predicate will likely be null, but may as well copy it */
+	newind->il_info->ii_Predicate = (List *)
+		copyObject(indexInfo->ii_Predicate);
 
 	newind->il_next = ILHead;
 	ILHead = newind;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f0fa73e83dd..b48a13f9e17 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.156 2001/07/15 22:48:17 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.157 2001/07/16 05:06:57 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -510,7 +510,7 @@ UpdateIndexRelation(Oid indexoid,
 	 * allocate a Form_pg_index big enough to hold the index-predicate (if
 	 * any) in string form
 	 */
-	if (indexInfo->ii_Predicate != NULL)
+	if (indexInfo->ii_Predicate != NIL)
 	{
 		predString = nodeToString(indexInfo->ii_Predicate);
 		predText = DatumGetTextP(DirectFunctionCall1(textin,
@@ -587,87 +587,6 @@ UpdateIndexRelation(Oid indexoid,
 }
 
 /* ----------------------------------------------------------------
- *		UpdateIndexPredicate
- * ----------------------------------------------------------------
- */
-void
-UpdateIndexPredicate(Oid indexoid, Node *oldPred, Node *predicate)
-{
-	Node	   *newPred;
-	char	   *predString;
-	text	   *predText;
-	Relation	pg_index;
-	HeapTuple	tuple;
-	HeapTuple	newtup;
-	int			i;
-	Datum		values[Natts_pg_index];
-	char		nulls[Natts_pg_index];
-	char		replace[Natts_pg_index];
-
-	/*
-	 * Construct newPred as a CNF expression equivalent to the OR of the
-	 * original partial-index predicate ("oldPred") and the extension
-	 * predicate ("predicate").
-	 *
-	 * This should really try to process the result to change things like
-	 * "a>2 OR a>1" to simply "a>1", but for now all it does is make sure
-	 * that if the extension predicate is NULL (i.e., it is being extended
-	 * to be a complete index), then newPred will be NULL - in effect,
-	 * changing "a>2 OR TRUE" to "TRUE". --Nels, Jan '93
-	 */
-	newPred = NULL;
-	if (predicate != NULL)
-	{
-		newPred = (Node *) make_orclause(lcons(make_andclause((List *) predicate),
-								  lcons(make_andclause((List *) oldPred),
-										NIL)));
-		newPred = (Node *) cnfify((Expr *) newPred, true);
-	}
-
-	/* translate the index-predicate to string form */
-	if (newPred != NULL)
-	{
-		predString = nodeToString(newPred);
-		predText = DatumGetTextP(DirectFunctionCall1(textin,
-										   CStringGetDatum(predString)));
-		pfree(predString);
-	}
-	else
-		predText = DatumGetTextP(DirectFunctionCall1(textin,
-												   CStringGetDatum("")));
-
-	/* open the index system catalog relation */
-	pg_index = heap_openr(IndexRelationName, RowExclusiveLock);
-
-	tuple = SearchSysCache(INDEXRELID,
-						   ObjectIdGetDatum(indexoid),
-						   0, 0, 0);
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "UpdateIndexPredicate: cache lookup failed for index %u",
-			 indexoid);
-
-	for (i = 0; i < Natts_pg_index; i++)
-	{
-		nulls[i] = heap_attisnull(tuple, i + 1) ? 'n' : ' ';
-		replace[i] = ' ';
-		values[i] = (Datum) NULL;
-	}
-
-	replace[Anum_pg_index_indpred - 1] = 'r';
-	values[Anum_pg_index_indpred - 1] = PointerGetDatum(predText);
-
-	newtup = heap_modifytuple(tuple, pg_index, values, nulls, replace);
-
-	simple_heap_update(pg_index, &newtup->t_self, newtup);
-
-	heap_freetuple(newtup);
-	ReleaseSysCache(tuple);
-
-	heap_close(pg_index, RowExclusiveLock);
-	pfree(predText);
-}
-
-/* ----------------------------------------------------------------
  *		InitIndexStrategy
  *
  * XXX this is essentially the same as relcache.c's
@@ -1084,7 +1003,7 @@ BuildIndexInfo(HeapTuple indexTuple)
 		pfree(predString);
 	}
 	else
-		ii->ii_Predicate = NULL;
+		ii->ii_Predicate = NIL;
 
 	/* Other info */
 	ii->ii_Unique = indexStruct->indisunique;
@@ -1684,7 +1603,7 @@ IndexBuildHeapScan(Relation heapRelation,
 	Datum		attdata[INDEX_MAX_KEYS];
 	char		nulls[INDEX_MAX_KEYS];
 	double		reltuples;
-	Node	   *predicate = indexInfo->ii_Predicate;
+	List	   *predicate = indexInfo->ii_Predicate;
 	TupleTable	tupleTable;
 	TupleTableSlot *slot;
 	ExprContext *econtext;
@@ -1708,7 +1627,7 @@ IndexBuildHeapScan(Relation heapRelation,
 	 * We construct the ExprContext anyway since we need a per-tuple
 	 * temporary memory context for function evaluation -- tgl July 00
 	 */
-	if (predicate != NULL)
+	if (predicate != NIL)
 	{
 		tupleTable = ExecCreateTupleTable(1);
 		slot = ExecAllocTableSlot(tupleTable);
@@ -1831,12 +1750,12 @@ IndexBuildHeapScan(Relation heapRelation,
 		 * VACUUM doesn't complain about tuple count mismatch for partial
 		 * indexes.
 		 */
-		if (predicate != NULL)
+		if (predicate != NIL)
 		{
 			if (! tupleIsAlive)
 				continue;
 			ExecStoreTuple(heapTuple, slot, InvalidBuffer, false);
-			if (!ExecQual((List *) predicate, econtext, false))
+			if (!ExecQual(predicate, econtext, false))
 				continue;
 		}
 
@@ -1865,7 +1784,7 @@ IndexBuildHeapScan(Relation heapRelation,
 
 	heap_endscan(scan);
 
-	if (predicate != NULL)
+	if (predicate != NIL)
 		ExecDropTupleTable(tupleTable, true);
 	FreeExprContext(econtext);
 
diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 4fcbeeceb6c..744129f726f 100644
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.135 2001/07/15 22:48:17 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.136 2001/07/16 05:06:57 tgl Exp $
  *
  * NOTES
  *	  The PerformAddAttribute() code, like most of the relation
@@ -1882,7 +1882,7 @@ AlterTableCreateToastTable(const char *relationName, bool silent)
 	indexInfo->ii_NumIndexAttrs = 1;
 	indexInfo->ii_NumKeyAttrs = 1;
 	indexInfo->ii_KeyAttrNumbers[0] = 1;
-	indexInfo->ii_Predicate = NULL;
+	indexInfo->ii_Predicate = NIL;
 	indexInfo->ii_FuncOid = InvalidOid;
 	indexInfo->ii_Unique = false;
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 7398b0b0ce5..6a85324bdc0 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/indexcmds.c,v 1.51 2001/07/15 22:48:17 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/indexcmds.c,v 1.52 2001/07/16 05:06:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,8 +45,6 @@
 
 /* non-export function prototypes */
 static void CheckPredicate(List *predList, List *rangeTable, Oid baseRelOid);
-static void CheckPredExpr(Node *predicate, List *rangeTable, Oid baseRelOid);
-static void CheckPredClause(Expr *predicate, List *rangeTable, Oid baseRelOid);
 static void FuncIndexArgs(IndexInfo *indexInfo, Oid *classOidP,
 			  IndexElem *funcIndex,
 			  Oid relId,
@@ -144,12 +142,8 @@ DefineIndex(char *heapRelationName,
 	}
 
 	/*
-	 * Convert the partial-index predicate from parsetree form to plan
-	 * form, so it can be readily evaluated during index creation. Note:
-	 * "predicate" comes in as a list containing (1) the predicate itself
-	 * (a where_clause), and (2) a corresponding range table.
-	 *
-	 * [(1) is 'predicate' and (2) is 'rangetable' now. - ay 10/94]
+	 * Convert the partial-index predicate from parsetree form to
+	 * an implicit-AND qual expression, for easier evaluation at runtime.
 	 */
 	if (predicate != NULL && rangetable != NIL)
 	{
@@ -166,7 +160,7 @@ DefineIndex(char *heapRelationName,
 	 * structure
 	 */
 	indexInfo = makeNode(IndexInfo);
-	indexInfo->ii_Predicate = (Node *) cnfPred;
+	indexInfo->ii_Predicate = cnfPred;
 	indexInfo->ii_FuncOid = InvalidOid;
 	indexInfo->ii_Unique = unique;
 
@@ -219,154 +213,29 @@ DefineIndex(char *heapRelationName,
 
 
 /*
- * ExtendIndex
- *		Extends a partial index.
- */
-void
-ExtendIndex(char *indexRelationName, Expr *predicate, List *rangetable)
-{
-	Relation	heapRelation;
-	Relation	indexRelation;
-	Oid			accessMethodId,
-				indexId,
-				relationId;
-	HeapTuple	tuple;
-	Form_pg_index index;
-	List	   *cnfPred = NIL;
-	IndexInfo  *indexInfo;
-	Node	   *oldPred;
-
-	/*
-	 * Get index's relation id and access method id from pg_class
-	 */
-	tuple = SearchSysCache(RELNAME,
-						   PointerGetDatum(indexRelationName),
-						   0, 0, 0);
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "ExtendIndex: index \"%s\" not found",
-			 indexRelationName);
-	indexId = tuple->t_data->t_oid;
-	accessMethodId = ((Form_pg_class) GETSTRUCT(tuple))->relam;
-	ReleaseSysCache(tuple);
-
-	/*
-	 * Extract info from the pg_index tuple for the index
-	 */
-	tuple = SearchSysCache(INDEXRELID,
-						   ObjectIdGetDatum(indexId),
-						   0, 0, 0);
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "ExtendIndex: relation \"%s\" is not an index",
-			 indexRelationName);
-	index = (Form_pg_index) GETSTRUCT(tuple);
-	Assert(index->indexrelid == indexId);
-	relationId = index->indrelid;
-	indexInfo = BuildIndexInfo(tuple);
-	oldPred = indexInfo->ii_Predicate;
-	ReleaseSysCache(tuple);
-
-	if (oldPred == NULL)
-		elog(ERROR, "ExtendIndex: \"%s\" is not a partial index",
-			 indexRelationName);
-
-	/*
-	 * Convert the extension predicate from parsetree form to plan form,
-	 * so it can be readily evaluated during index creation. Note:
-	 * "predicate" comes in two parts (1) the predicate expression itself,
-	 * and (2) a corresponding range table.
-	 *
-	 * XXX I think this code is broken --- index_build expects a single
-	 * expression not a list --- tgl Jul 00
-	 */
-	if (rangetable != NIL)
-	{
-		cnfPred = cnfify((Expr *) copyObject(predicate), true);
-		fix_opids((Node *) cnfPred);
-		CheckPredicate(cnfPred, rangetable, relationId);
-	}
-
-	/* pass new predicate to index_build */
-	indexInfo->ii_Predicate = (Node *) cnfPred;
-
-	/* Open heap and index rels, and get suitable locks */
-	heapRelation = heap_open(relationId, ShareLock);
-	indexRelation = index_open(indexId);
-
-	/* Obtain exclusive lock on it, just to be sure */
-	LockRelation(indexRelation, AccessExclusiveLock);
-
-	InitIndexStrategy(indexInfo->ii_NumIndexAttrs,
-					  indexRelation, accessMethodId);
-
-	/*
-	 * XXX currently BROKEN: if we want to support EXTEND INDEX, oldPred
-	 * needs to be passed through to IndexBuildHeapScan.  We could do this
-	 * without help from the index AMs if we added an oldPred field to the
-	 * IndexInfo struct.  Currently I'm expecting that EXTEND INDEX will
-	 * get removed, so I'm not going to do that --- tgl 7/14/01
-	 */
-
-	index_build(heapRelation, indexRelation, indexInfo);
-
-	/* heap and index rels are closed as a side-effect of index_build */
-}
-
-
-/*
  * CheckPredicate
  *		Checks that the given list of partial-index predicates refer
- *		(via the given range table) only to the given base relation oid,
- *		and that they're in a form the planner can handle, i.e.,
- *		boolean combinations of "ATTR OP CONST" (yes, for now, the ATTR
- *		has to be on the left).
+ *		(via the given range table) only to the given base relation oid.
+ *
+ * This used to also constrain the form of the predicate to forms that
+ * indxpath.c could do something with.  However, that seems overly
+ * restrictive.  One useful application of partial indexes is to apply
+ * a UNIQUE constraint across a subset of a table, and in that scenario
+ * any evaluatable predicate will work.  So accept any predicate here
+ * (except ones requiring a plan), and let indxpath.c fend for itself.
  */
 
 static void
 CheckPredicate(List *predList, List *rangeTable, Oid baseRelOid)
 {
-	List	   *item;
-
-	foreach(item, predList)
-		CheckPredExpr(lfirst(item), rangeTable, baseRelOid);
-}
-
-static void
-CheckPredExpr(Node *predicate, List *rangeTable, Oid baseRelOid)
-{
-	List	   *clauses = NIL,
-			   *clause;
-
-	if (is_opclause(predicate))
-	{
-		CheckPredClause((Expr *) predicate, rangeTable, baseRelOid);
-		return;
-	}
-	else if (or_clause(predicate) || and_clause(predicate))
-		clauses = ((Expr *) predicate)->args;
-	else
-		elog(ERROR, "Unsupported partial-index predicate expression type");
-
-	foreach(clause, clauses)
-		CheckPredExpr(lfirst(clause), rangeTable, baseRelOid);
-}
-
-static void
-CheckPredClause(Expr *predicate, List *rangeTable, Oid baseRelOid)
-{
-	Var		   *pred_var;
-	Const	   *pred_const;
-
-	pred_var = (Var *) get_leftop(predicate);
-	pred_const = (Const *) get_rightop(predicate);
-
-	if (!IsA(predicate->oper, Oper) ||
-		!IsA(pred_var, Var) ||
-		!IsA(pred_const, Const))
-		elog(ERROR, "Unsupported partial-index predicate clause type");
-
-	if (getrelid(pred_var->varno, rangeTable) != baseRelOid)
+	if (length(rangeTable) != 1 || getrelid(1, rangeTable) != baseRelOid)
 		elog(ERROR,
-		 "Partial-index predicates may refer only to the base relation");
+			 "Partial-index predicates may refer only to the base relation");
+
+	if (contain_subplans((Node *) predList))
+		elog(ERROR, "Cannot use subselect in index predicate");
+	if (contain_agg_clause((Node *) predList))
+		elog(ERROR, "Cannot use aggregate in index predicate");
 }
 
 
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 9465604b584..2c76c9b7d98 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.76 2001/07/15 22:48:17 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execUtils.c,v 1.77 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -641,7 +641,7 @@ ExecInsertIndexTuples(TupleTableSlot *slot,
 	for (i = 0; i < numIndices; i++)
 	{
 		IndexInfo  *indexInfo;
-		Node	   *predicate;
+		List	   *predicate;
 		InsertIndexResult result;
 
 		if (relationDescs[i] == NULL)
@@ -649,10 +649,10 @@ ExecInsertIndexTuples(TupleTableSlot *slot,
 
 		indexInfo = indexInfoArray[i];
 		predicate = indexInfo->ii_Predicate;
-		if (predicate != NULL)
+		if (predicate != NIL)
 		{
 			/* Skip this index-update if the predicate isn't satisfied */
-			if (!ExecQual((List *) predicate, econtext, false))
+			if (!ExecQual(predicate, econtext, false))
 				continue;
 		}
 
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 477fa6ed5ca..bdff8fe7e73 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.108 2001/06/25 21:11:43 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.109 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -195,8 +195,13 @@ create_index_paths(Query *root, RelOptInfo *rel)
 		 * 4. Generate an indexscan path if there are relevant restriction
 		 * clauses OR the index ordering is potentially useful for later
 		 * merging or final output ordering.
+		 *
+		 * If there is a predicate, consider it anyway since the index
+		 * predicate has already been found to match the query.
 		 */
-		if (restrictclauses != NIL || useful_pathkeys != NIL)
+		if (restrictclauses != NIL ||
+			useful_pathkeys != NIL ||
+			index->indpred != NIL)
 			add_path(rel, (Path *)
 					 create_index_path(root, rel, index,
 									   restrictclauses,
@@ -974,18 +979,18 @@ pred_test(List *predicate_list, List *restrictinfo_list, List *joininfo_list)
 	 * clauses (those in restrictinfo_list). --Nels, Dec '92
 	 */
 
-	if (predicate_list == NULL)
+	if (predicate_list == NIL)
 		return true;			/* no predicate: the index is usable */
-	if (restrictinfo_list == NULL)
+	if (restrictinfo_list == NIL)
 		return false;			/* no restriction clauses: the test must
 								 * fail */
 
 	foreach(pred, predicate_list)
 	{
-
 		/*
 		 * if any clause is not implied, the whole predicate is not
-		 * implied
+		 * implied.  Note that checking for sub-ANDs here is redundant
+		 * if the predicate has been cnfify()-ed.
 		 */
 		if (and_clause(lfirst(pred)))
 		{
@@ -1011,15 +1016,16 @@ pred_test(List *predicate_list, List *restrictinfo_list, List *joininfo_list)
 static bool
 one_pred_test(Expr *predicate, List *restrictinfo_list)
 {
-	RestrictInfo *restrictinfo;
 	List	   *item;
 
 	Assert(predicate != NULL);
 	foreach(item, restrictinfo_list)
 	{
-		restrictinfo = (RestrictInfo *) lfirst(item);
+		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(item);
+
 		/* if any clause implies the predicate, return true */
-		if (one_pred_clause_expr_test(predicate, (Node *) restrictinfo->clause))
+		if (one_pred_clause_expr_test(predicate,
+									  (Node *) restrictinfo->clause))
 			return true;
 	}
 	return false;
@@ -1055,7 +1061,6 @@ one_pred_clause_expr_test(Expr *predicate, Node *clause)
 		items = ((Expr *) clause)->args;
 		foreach(item, items)
 		{
-
 			/*
 			 * if any AND item implies the predicate, the whole clause
 			 * does
@@ -1102,7 +1107,6 @@ one_pred_clause_test(Expr *predicate, Node *clause)
 		items = predicate->args;
 		foreach(item, items)
 		{
-
 			/*
 			 * if any item is not implied, the whole predicate is not
 			 * implied
@@ -1177,26 +1181,30 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 				test_strategy;
 	Oper	   *test_oper;
 	Expr	   *test_expr;
-	bool		test_result,
-				isNull;
+	Datum		test_result;
+	bool		isNull;
 	Relation	relation;
 	HeapScanDesc scan;
 	HeapTuple	tuple;
 	ScanKeyData entry[3];
 	Form_pg_amop aform;
+	ExprContext *econtext;
+
+	/* Check the basic form; for now, only allow the simplest case */
+	/* Note caller already verified is_opclause(predicate) */
+	if (!is_opclause(clause))
+		return false;
 
 	pred_var = (Var *) get_leftop(predicate);
 	pred_const = (Const *) get_rightop(predicate);
 	clause_var = (Var *) get_leftop((Expr *) clause);
 	clause_const = (Const *) get_rightop((Expr *) clause);
 
-	/* Check the basic form; for now, only allow the simplest case */
-	if (!is_opclause(clause) ||
-		!IsA(clause_var, Var) ||
+	if (!IsA(clause_var, Var) ||
 		clause_const == NULL ||
 		!IsA(clause_const, Const) ||
-		!IsA(predicate->oper, Oper) ||
 		!IsA(pred_var, Var) ||
+		pred_const == NULL ||
 		!IsA(pred_const, Const))
 		return false;
 
@@ -1211,10 +1219,15 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 	pred_op = ((Oper *) ((Expr *) predicate)->oper)->opno;
 	clause_op = ((Oper *) ((Expr *) clause)->oper)->opno;
 
-
 	/*
 	 * 1. Find a "btree" strategy number for the pred_op
+	 *
+	 * XXX consider using syscache lookups for these searches.  Right
+	 * now we don't have caches that match all of the search conditions,
+	 * but reconsider it after upcoming restructuring of pg_opclass.
 	 */
+	relation = heap_openr(AccessMethodOperatorRelationName, AccessShareLock);
+
 	ScanKeyEntryInitialize(&entry[0], 0,
 						   Anum_pg_amop_amopid,
 						   F_OIDEQ,
@@ -1225,8 +1238,6 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 						   F_OIDEQ,
 						   ObjectIdGetDatum(pred_op));
 
-	relation = heap_openr(AccessMethodOperatorRelationName, AccessShareLock);
-
 	/*
 	 * The following assumes that any given operator will only be in a
 	 * single btree operator class.  This is true at least for all the
@@ -1254,7 +1265,6 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 
 	heap_endscan(scan);
 
-
 	/*
 	 * 2. From the same opclass, find a strategy num for the clause_op
 	 */
@@ -1281,13 +1291,12 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 
 	/* Get the restriction clause operator's strategy number (1 to 5) */
 	clause_strategy = (StrategyNumber) aform->amopstrategy;
-	heap_endscan(scan);
 
+	heap_endscan(scan);
 
 	/*
 	 * 3. Look up the "test" strategy number in the implication table
 	 */
-
 	test_strategy = BT_implic_table[clause_strategy - 1][pred_strategy - 1];
 	if (test_strategy == 0)
 	{
@@ -1298,7 +1307,6 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 	/*
 	 * 4. From the same opclass, find the operator for the test strategy
 	 */
-
 	ScanKeyEntryInitialize(&entry[2], 0,
 						   Anum_pg_amop_amopstrategy,
 						   F_INT2EQ,
@@ -1329,19 +1337,20 @@ clause_pred_clause_test(Expr *predicate, Node *clause)
 						 InvalidOid,	/* opid */
 						 BOOLOID);		/* opresulttype */
 	replace_opid(test_oper);
-
 	test_expr = make_opclause(test_oper,
-							  copyObject(clause_const),
-							  copyObject(pred_const));
+							  (Var *) clause_const,
+							  (Var *) pred_const);
 
-	test_result = ExecEvalExpr((Node *) test_expr, NULL, &isNull, NULL);
+	econtext = MakeExprContext(NULL, TransactionCommandContext);
+	test_result = ExecEvalExpr((Node *) test_expr, econtext, &isNull, NULL);
+	FreeExprContext(econtext);
 
 	if (isNull)
 	{
 		elog(DEBUG, "clause_pred_clause_test: null test result");
 		return false;
 	}
-	return test_result;
+	return DatumGetBool(test_result);
 }
 
 
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 7f1f3b402a4..1377fc06a49 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.74 2001/06/05 05:26:04 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.75 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -362,6 +362,13 @@ create_index_path(Query *root,
 	pathnode->alljoinquals = false;
 	pathnode->rows = rel->rows;
 
+	/*
+	 * Not sure if this is necessary, but it should help if the
+	 * statistics are too far off
+	 */
+	if (index->indpred && index->tuples < pathnode->rows)
+		pathnode->rows = index->tuples;
+
 	cost_index(&pathnode->path, root, rel, index, indexquals, false);
 
 	return pathnode;
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 9d6dfeb69a7..186fa124507 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.192 2001/07/04 17:36:54 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.193 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,7 +45,6 @@ static Query *transformStmt(ParseState *pstate, Node *stmt);
 static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
 static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
 static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
-static Query *transformExtendStmt(ParseState *pstate, ExtendStmt *stmt);
 static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
 static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
 static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
@@ -148,10 +147,6 @@ transformStmt(ParseState *pstate, Node *parseTree)
 			result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
 			break;
 
-		case T_ExtendStmt:
-			result = transformExtendStmt(pstate, (ExtendStmt *) parseTree);
-			break;
-
 		case T_RuleStmt:
 			result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
 			break;
@@ -1630,43 +1625,34 @@ static Query *
 transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
 {
 	Query	   *qry;
+	RangeTblEntry *rte;
 
 	qry = makeNode(Query);
 	qry->commandType = CMD_UTILITY;
 
 	/* take care of the where clause */
-	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);
-
-	qry->hasSubLinks = pstate->p_hasSubLinks;
-
-	stmt->rangetable = pstate->p_rtable;
-
-	qry->utilityStmt = (Node *) stmt;
-
-	return qry;
-}
-
-/*
- * transformExtendStmt -
- *	  transform the qualifications of the Extend Index Statement
- *
- */
-static Query *
-transformExtendStmt(ParseState *pstate, ExtendStmt *stmt)
-{
-	Query	   *qry;
+	if (stmt->whereClause)
+	{
+		/*
+		 * Put the parent table into the rtable so that the WHERE clause can
+		 * refer to its fields without qualification.  Note that this only
+		 * works if the parent table already exists --- so we can't easily
+		 * support predicates on indexes created implicitly by CREATE TABLE.
+		 * Fortunately, that's not necessary.
+		 */
+		rte = addRangeTableEntry(pstate, stmt->relname, NULL, false, true);
 
-	qry = makeNode(Query);
-	qry->commandType = CMD_UTILITY;
+		/* no to join list, yes to namespace */
+		addRTEtoQuery(pstate, rte, false, true);
 
-	/* take care of the where clause */
-	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);
+		stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);
+	}
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
-
 	stmt->rangetable = pstate->p_rtable;
 
 	qry->utilityStmt = (Node *) stmt;
+
 	return qry;
 }
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index b83ca3783fd..99312049a83 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.236 2001/07/12 18:02:59 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.237 2001/07/16 05:06:58 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -135,7 +135,7 @@ static void doNegateFloat(Value *v);
 		CreateSchemaStmt, CreateSeqStmt, CreateStmt, CreateTrigStmt,
 		CreateUserStmt, CreatedbStmt, CursorStmt, DefineStmt, DeleteStmt,
 		DropGroupStmt, DropPLangStmt, DropSchemaStmt, DropStmt, DropTrigStmt,
-		DropUserStmt, DropdbStmt, ExplainStmt, ExtendStmt, FetchStmt,
+		DropUserStmt, DropdbStmt, ExplainStmt, FetchStmt,
 		GrantStmt, IndexStmt, InsertStmt, ListenStmt, LoadStmt, LockStmt,
 		NotifyStmt, OptimizableStmt, ProcedureStmt, ReindexStmt,
 		RemoveAggrStmt, RemoveFuncStmt, RemoveOperStmt,
@@ -345,7 +345,7 @@ static void doNegateFloat(Value *v);
 		BACKWARD, BEFORE, BINARY, BIT,
 		CACHE, CHECKPOINT, CLUSTER, COMMENT, COPY, CREATEDB, CREATEUSER, CYCLE,
 		DATABASE, DELIMITERS, DO,
-		EACH, ENCODING, EXCLUSIVE, EXPLAIN, EXTEND,
+		EACH, ENCODING, EXCLUSIVE, EXPLAIN,
 		FORCE, FORWARD, FUNCTION, HANDLER,
 		ILIKE, INCREMENT, INDEX, INHERITS, INSTEAD, ISNULL,
 		LANCOMPILER, LIMIT, LISTEN, LOAD, LOCATION, LOCK_P,
@@ -450,7 +450,6 @@ stmt :	AlterSchemaStmt
 		| DropPLangStmt
 		| DropTrigStmt
 		| DropUserStmt
-		| ExtendStmt
 		| ExplainStmt
 		| FetchStmt
 		| GrantStmt
@@ -2392,14 +2391,14 @@ RevokeStmt:  REVOKE privileges ON opt_table relation_name_list FROM grantee_list
  *
  *		QUERY:
  *				create index <indexname> on <relname>
- *				  using <access> "(" (<col> with <op>)+ ")" [with
- *				  <target_list>]
+ *				  [ using <access> ] "(" (<col> with <op>)+ ")"
+ *				  [ with <parameters> ]
+ *				  [ where <predicate> ]
  *
- *	[where <qual>] is not supported anymore
  *****************************************************************************/
 
 IndexStmt:	CREATE index_opt_unique INDEX index_name ON relation_name
-			access_method_clause '(' index_params ')' opt_with
+			access_method_clause '(' index_params ')' opt_with where_clause
 				{
 					IndexStmt *n = makeNode(IndexStmt);
 					n->unique = $2;
@@ -2408,7 +2407,7 @@ IndexStmt:	CREATE index_opt_unique INDEX index_name ON relation_name
 					n->accessMethod = $7;
 					n->indexParams = $9;
 					n->withClause = $11;
-					n->whereClause = NULL;
+					n->whereClause = $12;
 					$$ = (Node *)n;
 				}
 		;
@@ -2474,22 +2473,6 @@ opt_class:  class
 /*****************************************************************************
  *
  *		QUERY:
- *				extend index <indexname> [where <qual>]
- *
- *****************************************************************************/
-
-ExtendStmt:  EXTEND INDEX index_name where_clause
-				{
-					ExtendStmt *n = makeNode(ExtendStmt);
-					n->idxname = $3;
-					n->whereClause = $4;
-					$$ = (Node *)n;
-				}
-		;
-
-/*****************************************************************************
- *
- *		QUERY:
  *				execute recipe <recipeName>
  *
  *****************************************************************************/
@@ -5775,7 +5758,6 @@ ColLabel:  ColId						{ $$ = $1; }
 		| EXCEPT						{ $$ = "except"; }
 		| EXISTS						{ $$ = "exists"; }
 		| EXPLAIN						{ $$ = "explain"; }
-		| EXTEND						{ $$ = "extend"; }
 		| EXTRACT						{ $$ = "extract"; }
 		| FALSE_P						{ $$ = "false"; }
 		| FLOAT							{ $$ = "float"; }
diff --git a/src/backend/parser/keywords.c b/src/backend/parser/keywords.c
index ccdfb88a2e2..014b1198503 100644
--- a/src/backend/parser/keywords.c
+++ b/src/backend/parser/keywords.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.93 2001/06/19 22:39:11 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.94 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -109,7 +109,6 @@ static ScanKeyword ScanKeywords[] = {
 	{"execute", EXECUTE},
 	{"exists", EXISTS},
 	{"explain", EXPLAIN},
-	{"extend", EXTEND},
 	{"extract", EXTRACT},
 	{"false", FALSE_P},
 	{"fetch", FETCH},
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 5be50e7aade..a791a67715e 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.114 2001/06/18 16:13:21 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.115 2001/07/16 05:06:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -567,18 +567,6 @@ ProcessUtility(Node *parsetree,
 			DefineSequence((CreateSeqStmt *) parsetree);
 			break;
 
-		case T_ExtendStmt:
-			{
-				ExtendStmt *stmt = (ExtendStmt *) parsetree;
-
-				set_ps_display(commandTag = "EXTEND");
-
-				ExtendIndex(stmt->idxname,		/* index name */
-							(Expr *) stmt->whereClause, /* where */
-							stmt->rangetable);
-			}
-			break;
-
 		case T_RemoveAggrStmt:
 			{
 				RemoveAggrStmt *stmt = (RemoveAggrStmt *) parsetree;
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 5f7cfead6c1..afc2b63430b 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.79 2001/07/10 00:02:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.80 2001/07/16 05:06:59 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -40,6 +40,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+#include "catalog/heap.h"
 #include "catalog/pg_index.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_shadow.h"
@@ -555,6 +556,64 @@ pg_get_indexdef(PG_FUNCTION_ARGS)
 
 
 /* ----------
+ * get_expr			- Decompile an expression tree
+ *
+ * Input: an expression tree in nodeToString form, and a relation OID
+ *
+ * Output: reverse-listed expression
+ *
+ * Currently, the expression can only refer to a single relation, namely
+ * the one specified by the second parameter.  This is sufficient for
+ * partial indexes, column default expressions, etc.
+ * ----------
+ */
+Datum
+pg_get_expr(PG_FUNCTION_ARGS)
+{
+	text	*expr = PG_GETARG_TEXT_P(0);
+	Oid		relid = PG_GETARG_OID(1);
+	text	*result;
+	Node	*node;
+	List	*context;
+	char	*exprstr;
+	char	*relname;
+	char	*str;
+
+	/* Get the name for the relation */
+	relname = get_rel_name(relid);
+	if (relname == NULL)
+		PG_RETURN_NULL();		/* should we raise an error? */
+
+	/* Convert input TEXT object to C string */
+	exprstr = DatumGetCString(DirectFunctionCall1(textout,
+												  PointerGetDatum(expr)));
+
+	/* Convert expression to node tree */
+	node = (Node *) stringToNode(exprstr);
+
+	/*
+	 * If top level is a List, assume it is an implicit-AND structure,
+	 * and convert to explicit AND.  This is needed for partial index
+	 * predicates.
+	 */
+	if (node && IsA(node, List))
+	{
+		node = (Node *) make_ands_explicit((List *) node);
+	}
+
+	/* Deparse */
+	context = deparse_context_for(relname, relid);
+	str = deparse_expression(node, context, false);
+	
+	/* Pass the result back as TEXT */
+	result = DatumGetTextP(DirectFunctionCall1(textin,
+											   CStringGetDatum(str)));
+
+	PG_RETURN_TEXT_P(result);
+}
+
+
+/* ----------
  * get_userbyid			- Get a user name by usesysid and
  *				  fallback to 'unknown (UID=n)'
  * ----------
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 3ab3881c257..e0cfeefaee4 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.94 2001/06/25 21:11:44 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.95 2001/07/16 05:06:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -86,6 +86,7 @@
 #include "optimizer/cost.h"
 #include "optimizer/pathnode.h"
 #include "optimizer/plancat.h"
+#include "optimizer/prep.h"
 #include "parser/parse_func.h"
 #include "parser/parse_oper.h"
 #include "parser/parsetree.h"
@@ -2950,24 +2951,63 @@ genericcostestimate(Query *root, RelOptInfo *rel,
 {
 	double		numIndexTuples;
 	double		numIndexPages;
+	List	   *selectivityQuals = indexQuals;
 
-	/* Estimate the fraction of main-table tuples that will be visited */
-	*indexSelectivity = clauselist_selectivity(root, indexQuals,
-											   lfirsti(rel->relids));
+	/*
+	 * If the index is partial, AND the index predicate with the explicitly
+	 * given indexquals to produce a more accurate idea of the index
+	 * restriction.  This may produce redundant clauses, which we hope that
+	 * cnfify and clauselist_selectivity will deal with intelligently.
+	 *
+	 * Note that index->indpred and indexQuals are both in implicit-AND
+	 * form to start with, which we have to make explicit to hand to
+	 * canonicalize_qual, and then we get back implicit-AND form again.
+	 */
+	if (index->indpred != NIL)
+	{
+		Expr   *andedQuals;
 
-	/* Estimate the number of index tuples that will be visited */
-	numIndexTuples = *indexSelectivity * index->tuples;
+		andedQuals = make_ands_explicit(nconc(listCopy(index->indpred),
+											  indexQuals));
+		selectivityQuals = canonicalize_qual(andedQuals, true);
+	}
 
-	/* Estimate the number of index pages that will be retrieved */
-	numIndexPages = *indexSelectivity * index->pages;
+  	/* Estimate the fraction of main-table tuples that will be visited */
+ 	*indexSelectivity = clauselist_selectivity(root, selectivityQuals,
+  											   lfirsti(rel->relids));
 
 	/*
-	 * Always estimate at least one tuple and page are touched, even when
+	 * Estimate the number of tuples that will be visited.  We do it in
+	 * this rather peculiar-looking way in order to get the right answer
+	 * for partial indexes.  We can bound the number of tuples by the
+	 * index size, in any case.
+	 */
+	numIndexTuples = *indexSelectivity * rel->tuples;
+
+	if (numIndexTuples > index->tuples)
+		numIndexTuples = index->tuples;
+
+  	/*
+	 * Always estimate at least one tuple is touched, even when
 	 * indexSelectivity estimate is tiny.
 	 */
 	if (numIndexTuples < 1.0)
 		numIndexTuples = 1.0;
-	if (numIndexPages < 1.0)
+
+  	/*
+	 * Estimate the number of index pages that will be retrieved.
+	 *
+	 * For all currently-supported index types, the first page of the index
+	 * is a metadata page, and we should figure on fetching that plus a
+	 * pro-rated fraction of the remaining pages.
+	 */
+	if (index->pages > 1 && index->tuples > 0)
+	{
+		numIndexPages = (numIndexTuples / index->tuples) * (index->pages - 1);
+		numIndexPages += 1;		/* count the metapage too */
+		numIndexPages = ceil(numIndexPages);
+	}
+	else
 		numIndexPages = 1.0;
 
 	/*
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index a73bb7b5c8b..531fd9e497c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -22,7 +22,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.213 2001/07/03 20:21:49 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.214 2001/07/16 05:06:59 tgl Exp $
  *
  * Modifications - 6/10/96 - dave@bensoft.com - version 1.13.dhb
  *
@@ -1758,6 +1758,8 @@ clearIndInfo(IndInfo *ind, int numIndexes)
 			free(ind[i].indisunique);
 		if (ind[i].indisprimary)
 			free(ind[i].indisprimary);
+		if (ind[i].indpred)
+			free(ind[i].indpred);
 		for (a = 0; a < INDEX_MAX_KEYS; ++a)
 		{
 			if (ind[i].indkey[a])
@@ -2887,10 +2889,10 @@ getIndexes(int *numIndexes)
 	int			i_indoid;
 	int			i_oid;
 	int			i_indisprimary;
+	int			i_indpred;
 
 	/*
-	 * find all the user-defined indexes. We do not handle partial
-	 * indexes.
+	 * find all the user-defined indexes.
 	 *
 	 * Notice we skip indexes on system classes
 	 *
@@ -2902,7 +2904,7 @@ getIndexes(int *numIndexes)
 	appendPQExpBuffer(query,
 					  "SELECT i.oid, t1.oid as indoid, t1.relname as indexrelname, t2.relname as indrelname, "
 					  "i.indproc, i.indkey, i.indclass, "
-				  "a.amname as indamname, i.indisunique, i.indisprimary "
+				  "a.amname as indamname, i.indisunique, i.indisprimary, i.indpred "
 					"from pg_index i, pg_class t1, pg_class t2, pg_am a "
 				   "WHERE t1.oid = i.indexrelid and t2.oid = i.indrelid "
 					  "and t1.relam = a.oid and i.indexrelid > '%u'::oid "
@@ -2938,6 +2940,7 @@ getIndexes(int *numIndexes)
 	i_indclass = PQfnumber(res, "indclass");
 	i_indisunique = PQfnumber(res, "indisunique");
 	i_indisprimary = PQfnumber(res, "indisprimary");
+	i_indpred = PQfnumber(res, "indpred");
 
 	for (i = 0; i < ntups; i++)
 	{
@@ -2955,6 +2958,7 @@ getIndexes(int *numIndexes)
 						  INDEX_MAX_KEYS);
 		indinfo[i].indisunique = strdup(PQgetvalue(res, i, i_indisunique));
 		indinfo[i].indisprimary = strdup(PQgetvalue(res, i, i_indisprimary));
+		indinfo[i].indpred = strdup(PQgetvalue(res, i, i_indpred));
 	}
 	PQclear(res);
 	return indinfo;
@@ -4435,13 +4439,46 @@ dumpIndexes(Archive *fout, IndInfo *indinfo, int numIndexes,
 			{
 				/* need 2 printf's here cuz fmtId has static return area */
 				appendPQExpBuffer(q, " %s", fmtId(funcname, false));
-				appendPQExpBuffer(q, " (%s) %s );\n", attlist->data,
+				appendPQExpBuffer(q, " (%s) %s )", attlist->data,
 								  fmtId(classname[0], force_quotes));
 				free(funcname);
 				free(classname[0]);
 			}
 			else
-				appendPQExpBuffer(q, " %s );\n", attlist->data);
+				appendPQExpBuffer(q, " %s )", attlist->data);
+				
+			if (*indinfo[i].indpred) /* If there is an index predicate */
+			{
+				int numRows;
+				PQExpBuffer pred = createPQExpBuffer();
+				
+				appendPQExpBuffer(pred, "SELECT pg_get_expr(indpred,indrelid) as pred FROM pg_index WHERE oid = %s",
+								  indinfo[i].oid);
+				res = PQexec(g_conn, pred->data);
+				if (!res || PQresultStatus(res) != PGRES_TUPLES_OK)
+				{
+					fprintf(stderr, "dumpIndices(): SELECT (indpred) failed.  "
+							"Explanation from backend: '%s'.\n",
+							PQerrorMessage(g_conn));
+					exit_nicely();
+				}
+	
+				/* Sanity: Check we got only one tuple */
+				numRows = PQntuples(res);
+				if (numRows != 1)
+				{
+					fprintf(stderr, "dumpIndices(): SELECT (indpred) for index %s returned %d tuples. Expected 1.\n",
+							indinfo[i].indrelname, numRows);
+					exit_nicely();
+				}
+	
+				appendPQExpBuffer(q, " WHERE %s",
+								  PQgetvalue(res, 0, PQfnumber(res, "pred")));
+
+				PQclear(res);
+				destroyPQExpBuffer( pred );
+			}
+			appendPQExpBuffer(q, ";\n");
 
 			/*
 			 * We make the index belong to the owner of its table, which
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index a1a3bebd395..503d10f63dc 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_dump.h,v 1.65 2001/07/03 20:21:50 petere Exp $
+ * $Id: pg_dump.h,v 1.66 2001/07/16 05:06:59 tgl Exp $
  *
  * Modifications - 6/12/96 - dave@bensoft.com - version 1.13.dhb.2
  *
@@ -147,6 +147,7 @@ typedef struct _indInfo
 	char	   *indclass[INDEX_MAX_KEYS];		/* opclass of the keys */
 	char	   *indisunique;	/* is this index unique? */
 	char	   *indisprimary;	/* is this a PK index? */
+	char	   *indpred;		/* index predicate */
 } IndInfo;
 
 typedef struct _aggInfo
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index f93de9c2e90..0937cf9d929 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: index.h,v 1.36 2001/07/15 22:48:18 tgl Exp $
+ * $Id: index.h,v 1.37 2001/07/16 05:06:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,8 +30,6 @@ typedef void (*IndexBuildCallback) (Relation index,
 extern Form_pg_am AccessMethodObjectIdGetForm(Oid accessMethodObjectId,
 							MemoryContext resultCxt);
 
-extern void UpdateIndexPredicate(Oid indexoid, Node *oldPred, Node *predicate);
-
 extern void InitIndexStrategy(int numatts,
 				  Relation indexRelation,
 				  Oid accessMethodObjectId);
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index f249fcf2d9d..4acbe30e8ee 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_proc.h,v 1.197 2001/07/15 22:48:18 tgl Exp $
+ * $Id: pg_proc.h,v 1.198 2001/07/16 05:06:59 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -2146,6 +2146,9 @@ DATA(insert OID = 1642 (  pg_get_userbyid	   PGUID 12 f t f t 1 f 19 "23" 100 0
 DESCR("user name by UID (with fallback)");
 DATA(insert OID = 1643 (  pg_get_indexdef	   PGUID 12 f t f t 1 f 25 "26" 100 0 0 100  pg_get_indexdef - ));
 DESCR("index description");
+DATA(insert OID = 1716 (  pg_get_expr		   PGUID 12 f t f t 2 f 25 "25 26" 100 0 0 100  pg_get_expr - ));
+DESCR("deparse an encoded expression");
+
 
 /* Generic referential integrity constraint triggers */
 DATA(insert OID = 1644 (  RI_FKey_check_ins		PGUID 12 f t f t 0 f 0 "" 100 0 0 100  RI_FKey_check_ins - ));
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 98ba76613a1..47230e9144b 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: defrem.h,v 1.22 2001/01/24 19:43:23 momjian Exp $
+ * $Id: defrem.h,v 1.23 2001/07/16 05:07:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,7 +18,7 @@
 #include "tcop/dest.h"
 
 /*
- * prototypes in defind.c
+ * prototypes in indexcmds.c
  */
 extern void DefineIndex(char *heapRelationName,
 			char *indexRelationName,
@@ -29,9 +29,6 @@ extern void DefineIndex(char *heapRelationName,
 			bool primary,
 			Expr *predicate,
 			List *rangetable);
-extern void ExtendIndex(char *indexRelationName,
-			Expr *predicate,
-			List *rangetable);
 extern void RemoveIndex(char *name);
 extern void ReindexIndex(const char *indexRelationName, bool force);
 extern void ReindexTable(const char *relationName, bool force);
diff --git a/src/include/config.h.in b/src/include/config.h.in
index 941cfe8a066..70e9d6aa92b 100644
--- a/src/include/config.h.in
+++ b/src/include/config.h.in
@@ -8,7 +8,7 @@
  * or in config.h afterwards.  Of course, if you edit config.h, then your
  * changes will be overwritten the next time you run configure.
  *
- * $Id: config.h.in,v 1.167 2001/07/11 19:03:07 tgl Exp $
+ * $Id: config.h.in,v 1.168 2001/07/16 05:07:00 tgl Exp $
  */
 
 #ifndef CONFIG_H
@@ -310,7 +310,6 @@
 /* #define ACLDEBUG */
 /* #define RTDEBUG */
 /* #define GISTDEBUG */
-/* #define OMIT_PARTIAL_INDEX */
 
 /*
  * defining unsafe floats will make float4 and float8 ops faster
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 1dc68c192fe..4e1bc683d5b 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: execnodes.h,v 1.61 2001/06/01 02:41:36 tgl Exp $
+ * $Id: execnodes.h,v 1.62 2001/07/16 05:07:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -34,7 +34,7 @@
  *		NumKeyAttrs			number of key attributes for this index
  *							(ie, number of attrs from underlying relation)
  *		KeyAttrNumbers		underlying-rel attribute numbers used as keys
- *		Predicate			partial-index predicate, or NULL if none
+ *		Predicate			partial-index predicate, or NIL if none
  *		FuncOid				OID of function, or InvalidOid if not f. index
  *		FuncInfo			fmgr lookup data for function, if FuncOid valid
  *		Unique				is it a unique index?
@@ -46,7 +46,7 @@ typedef struct IndexInfo
 	int			ii_NumIndexAttrs;
 	int			ii_NumKeyAttrs;
 	AttrNumber	ii_KeyAttrNumbers[INDEX_MAX_KEYS];
-	Node	   *ii_Predicate;
+	List	   *ii_Predicate;
 	Oid			ii_FuncOid;
 	FmgrInfo	ii_FuncInfo;
 	bool		ii_Unique;
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index efb5c3dcb22..150acabc0a3 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: builtins.h,v 1.157 2001/07/11 22:14:03 momjian Exp $
+ * $Id: builtins.h,v 1.158 2001/07/16 05:07:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -337,6 +337,7 @@ extern Datum pg_get_ruledef(PG_FUNCTION_ARGS);
 extern Datum pg_get_viewdef(PG_FUNCTION_ARGS);
 extern Datum pg_get_indexdef(PG_FUNCTION_ARGS);
 extern Datum pg_get_userbyid(PG_FUNCTION_ARGS);
+extern Datum pg_get_expr(PG_FUNCTION_ARGS);
 extern char *deparse_expression(Node *expr, List *dpcontext,
 				   bool forceprefix);
 extern List *deparse_context_for(char *relname, Oid relid);
diff --git a/src/interfaces/ecpg/preproc/keywords.c b/src/interfaces/ecpg/preproc/keywords.c
index d7ee1d3455c..5792017871b 100644
--- a/src/interfaces/ecpg/preproc/keywords.c
+++ b/src/interfaces/ecpg/preproc/keywords.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/interfaces/ecpg/preproc/keywords.c,v 1.41 2001/06/01 06:23:19 meskes Exp $
+ *	  $Header: /cvsroot/pgsql/src/interfaces/ecpg/preproc/keywords.c,v 1.42 2001/07/16 05:07:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -109,7 +109,6 @@ static ScanKeyword ScanKeywords[] = {
 	{"execute", EXECUTE},
 	{"exists", EXISTS},
 	{"explain", EXPLAIN},
-	{"extend", EXTEND},
 	{"extract", EXTRACT},
 	{"false", FALSE_P},
 	{"fetch", FETCH},
@@ -265,6 +264,7 @@ static ScanKeyword ScanKeywords[] = {
 	{"type", TYPE_P},
 	{"union", UNION},
 	{"unique", UNIQUE},
+	{"unknown", UNKNOWN},
 	{"unlisten", UNLISTEN},
 	{"until", UNTIL},
 	{"update", UPDATE},
diff --git a/src/interfaces/ecpg/preproc/preproc.y b/src/interfaces/ecpg/preproc/preproc.y
index 902b1774121..88330ad3c1d 100644
--- a/src/interfaces/ecpg/preproc/preproc.y
+++ b/src/interfaces/ecpg/preproc/preproc.y
@@ -193,7 +193,7 @@ make_name(void)
                 SCHEMA, SCROLL, SECOND_P, SELECT, SESSION, SESSION_USER, SET, SOME, SUBSTRING,
                 TABLE, TEMPORARY, THEN, TIME, TIMESTAMP, TIMEZONE_HOUR,
 		TIMEZONE_MINUTE, TO, TRAILING, TRANSACTION, TRIM, TRUE_P,
-                UNION, UNIQUE, UPDATE, USER, USING,
+                UNION, UNIQUE, UNKNOWN, UPDATE, USER, USING,
                 VALUES, VARCHAR, VARYING, VIEW,
                 WHEN, WHERE, WITH, WITHOUT, WORK, YEAR_P, ZONE
 
@@ -217,7 +217,7 @@ make_name(void)
 		BACKWARD, BEFORE, BINARY, BIT, CACHE, CHECKPOINT, CLUSTER,
 		COMMENT, COPY, CREATEDB, CREATEUSER, CYCLE, DATABASE,
 		DELIMITERS, DO, EACH, ENCODING, EXCLUSIVE, EXPLAIN,
-		EXTEND, FORCE, FORWARD, FUNCTION, HANDLER, INCREMENT,
+		FORCE, FORWARD, FUNCTION, HANDLER, INCREMENT,
 		INDEX, INHERITS, INSTEAD, ISNULL, LANCOMPILER, LIMIT,
 		LISTEN, UNLISTEN, LOAD, LOCATION, LOCK_P, MAXVALUE,
 		MINVALUE, MODE, MOVE, NEW, NOCREATEDB, NOCREATEUSER,
@@ -260,7 +260,7 @@ make_name(void)
 %left		Op				/* multi-character ops and user-defined operators */
 %nonassoc	NOTNULL
 %nonassoc	ISNULL
-%nonassoc	IS NULL_P TRUE_P FALSE_P 
+%nonassoc	IS NULL_P TRUE_P FALSE_P UNKNOWN
 %left		'+' '-'
 %left		'*' '/' '%'
 %left		'^'
@@ -312,7 +312,7 @@ make_name(void)
 %type  <str>	RuleActionStmtOrEmpty RuleActionMulti func_as reindex_type
 %type  <str>    RuleStmt opt_column opt_name oper_argtypes
 %type  <str>    MathOp RemoveFuncStmt aggr_argtype for_update_clause
-%type  <str>    RemoveAggrStmt ExtendStmt opt_procedural select_no_parens
+%type  <str>    RemoveAggrStmt opt_procedural select_no_parens
 %type  <str>    RemoveOperStmt RenameStmt all_Op
 %type  <str>    VariableSetStmt var_value zone_value VariableShowStmt
 %type  <str>    VariableResetStmt AlterTableStmt DropUserStmt from_list
@@ -414,7 +414,6 @@ stmt:  AlterSchemaStmt 			{ output_statement($1, 0, NULL, connection); }
 		| DropPLangStmt		{ output_statement($1, 0, NULL, connection); }
 		| DropTrigStmt		{ output_statement($1, 0, NULL, connection); }
 		| DropUserStmt		{ output_statement($1, 0, NULL, connection); }
-		| ExtendStmt 		{ output_statement($1, 0, NULL, connection); }
 		| ExplainStmt		{ output_statement($1, 0, NULL, connection); }
 		| FetchStmt		{ output_statement($1, 1, NULL, connection); }
 		| GrantStmt		{ output_statement($1, 0, NULL, connection); }
@@ -1801,18 +1800,16 @@ RevokeStmt:  REVOKE privileges ON opt_table relation_name_list FROM grantee_list
  *
  *		QUERY:
  *				create index <indexname> on <relname>
- *				  using <access> "(" (<col> with <op>)+ ")" [with
- *				  <target_list>]
+ *				  [ using <access> ] "(" (<col> with <op>)+ ")"
+ *				  [ with <parameters> ]
+ *				  [ where <predicate> ]
  *
- *	[where <qual>] is not supported anymore
  *****************************************************************************/
 
 IndexStmt:	CREATE index_opt_unique INDEX index_name ON relation_name
-			access_method_clause '(' index_params ')' opt_with
+			access_method_clause '(' index_params ')' opt_with where_clause
 				{
-					/* should check that access_method is valid,
-					   etc ... but doesn't */
-					$$ = cat_str(11, make_str("create"), $2, make_str("index"), $4, make_str("on"), $6, $7, make_str("("), $9, make_str(")"), $11);
+					$$ = cat_str(12, make_str("create"), $2, make_str("index"), $4, make_str("on"), $6, $7, make_str("("), $9, make_str(")"), $11, $12);
 				}
 		;
 
@@ -1866,19 +1863,6 @@ opt_class:  class			{
 		| /*EMPTY*/			{ $$ = EMPTY; }
 		;
 
-/*****************************************************************************
- *
- *		QUERY:
- *				extend index <indexname> [where <qual>]
- *
- *****************************************************************************/
-
-ExtendStmt:  EXTEND INDEX index_name where_clause
-				{
-					$$ = cat_str(3, make_str("extend index"), $3, $4);
-				}
-		;
-
 
 /*****************************************************************************
  *
@@ -3324,15 +3308,23 @@ a_expr:  c_expr
 		 *  but let's make them expressions to allow the optimizer
 		 *  a chance to eliminate them if a_expr is a constant string.
 		 * - thomas 1997-12-22
+		 *
+		 *  Created BooleanTest Node type, and changed handling
+		 *  for NULL inputs
+		 * - jec 2001-06-18
 		 */
 		| a_expr IS TRUE_P
 				{	$$ = cat2_str($1, make_str("is true")); }
-		| a_expr IS NOT FALSE_P
-				{	$$ = cat2_str($1, make_str("is not false")); }
-		| a_expr IS FALSE_P
-				{	$$ = cat2_str($1, make_str("is false")); }
 		| a_expr IS NOT TRUE_P
 				{	$$ = cat2_str($1, make_str("is not true")); }
+		| a_expr IS FALSE_P
+				{	$$ = cat2_str($1, make_str("is false")); }
+		| a_expr IS NOT FALSE_P
+				{	$$ = cat2_str($1, make_str("is not false")); }
+		| a_expr IS UNKNOWN
+				{	$$ = cat2_str($1, make_str("is unknown")); }
+		| a_expr IS NOT UNKNOWN
+				{	$$ = cat2_str($1, make_str("is not unknown")); }
 		| a_expr BETWEEN b_expr AND b_expr	%prec BETWEEN
 				{
 					$$ = cat_str(5, $1, make_str("between"), $3, make_str("and"), $5); 
@@ -5152,7 +5144,6 @@ ECPGColLabel:  ECPGColId	{ $$ = $1; }
 		| EXCEPT	{ $$ = make_str("except"); }
 		| EXISTS	{ $$ = make_str("exists"); }
 		| EXPLAIN	{ $$ = make_str("explain"); }
-		| EXTEND	{ $$ = make_str("extend"); }
 		| EXTRACT	{ $$ = make_str("extract"); }
 		| FALSE_P	{ $$ = make_str("false"); }
 		| FOR		{ $$ = make_str("for"); }
@@ -5217,6 +5208,7 @@ ECPGColLabel:  ECPGColId	{ $$ = $1; }
 		| TRIM		{ $$ = make_str("trim"); }
 		| TRUE_P	{ $$ = make_str("true"); }
 		| UNIQUE	{ $$ = make_str("unique"); }
+		| UNKNOWN	{ $$ = make_str("unknown"); }
 		| USER		{ $$ = make_str("user"); }
 		| USING		{ $$ = make_str("using"); }
 		| VACUUM	{ $$ = make_str("vacuum"); }
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index 3e727517741..06eeeecdd43 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -32,16 +32,13 @@ CREATE INDEX bt_txt_index ON bt_txt_heap USING btree (seqno text_ops);
 CREATE INDEX bt_f8_index ON bt_f8_heap USING btree (seqno float8_ops);
 --
 -- BTREE partial indices
--- partial indices are not supported in PostgreSQL
 --
---CREATE INDEX onek2_u1_prtl ON onek2 USING btree(unique1 int4_ops)
---	where onek2.unique1 < 20 or onek2.unique1 > 980;
---CREATE INDEX onek2_u2_prtl ON onek2 USING btree(unique2 int4_ops)
---	where onek2.stringu1 < 'B';
--- EXTEND INDEX onek2_u2_prtl where onek2.stringu1 < 'C';
--- EXTEND INDEX onek2_u2_prtl;
--- CREATE INDEX onek2_stu1_prtl ON onek2 USING btree(stringu1 name_ops)
---	where onek2.stringu1 >= 'J' and onek2.stringu1 < 'K';
+CREATE INDEX onek2_u1_prtl ON onek2 USING btree(unique1 int4_ops)
+	where unique1 < 20 or unique1 > 980;
+CREATE INDEX onek2_u2_prtl ON onek2 USING btree(unique2 int4_ops)
+	where stringu1 < 'B';
+CREATE INDEX onek2_stu1_prtl ON onek2 USING btree(stringu1 name_ops)
+	where onek2.stringu1 >= 'J' and onek2.stringu1 < 'K';
 --
 -- RTREE
 -- 
diff --git a/src/test/regress/expected/portals_p2.out b/src/test/regress/expected/portals_p2.out
index 558397f5c9d..7a9cf696746 100644
--- a/src/test/regress/expected/portals_p2.out
+++ b/src/test/regress/expected/portals_p2.out
@@ -1,7 +1,6 @@
 --
 -- PORTALS_P2
 --
--- EXTEND INDEX onek2_u1_prtl WHERE onek2.unique1 <= 60;
 BEGIN;
 DECLARE foo13 CURSOR FOR 
    SELECT * FROM onek WHERE unique1 = 50;
diff --git a/src/test/regress/expected/sanity_check.out b/src/test/regress/expected/sanity_check.out
index 5f5911c09c6..ac0e344c747 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -29,6 +29,7 @@ SELECT relname, relhasindex
  num_exp_sqrt        | t
  num_exp_sub         | t
  onek                | t
+ onek2               | t
  pg_aggregate        | t
  pg_am               | t
  pg_amop             | t
@@ -57,5 +58,5 @@ SELECT relname, relhasindex
  shighway            | t
  tenk1               | t
  tenk2               | t
-(47 rows)
+(48 rows)
 
diff --git a/src/test/regress/expected/select.out b/src/test/regress/expected/select.out
index ed6cbac1df0..7974d141c54 100644
--- a/src/test/regress/expected/select.out
+++ b/src/test/regress/expected/select.out
@@ -205,24 +205,88 @@ SELECT onek.unique1, onek.string4
 (20 rows)
 
 --
--- partial btree index
+-- test partial btree indexes
+--
+-- As of 7.2, planner probably won't pick an indexscan without stats,
+-- so ANALYZE first.
+--
+ANALYZE onek2;
+--
 -- awk '{if($1<10){print $0;}else{next;}}' onek.data | sort +0n -1
 --
---SELECT onek2.* WHERE onek2.unique1 < 10;
+SELECT onek2.* WHERE onek2.unique1 < 10;
+ unique1 | unique2 | two | four | ten | twenty | hundred | thousand | twothousand | fivethous | tenthous | odd | even | stringu1 | stringu2 | string4 
+---------+---------+-----+------+-----+--------+---------+----------+-------------+-----------+----------+-----+------+----------+----------+---------
+       0 |     998 |   0 |    0 |   0 |      0 |       0 |        0 |           0 |         0 |        0 |   0 |    1 | AAAAAA   | KMBAAA   | OOOOxx
+       1 |     214 |   1 |    1 |   1 |      1 |       1 |        1 |           1 |         1 |        1 |   2 |    3 | BAAAAA   | GIAAAA   | OOOOxx
+       2 |     326 |   0 |    2 |   2 |      2 |       2 |        2 |           2 |         2 |        2 |   4 |    5 | CAAAAA   | OMAAAA   | OOOOxx
+       3 |     431 |   1 |    3 |   3 |      3 |       3 |        3 |           3 |         3 |        3 |   6 |    7 | DAAAAA   | PQAAAA   | VVVVxx
+       4 |     833 |   0 |    0 |   4 |      4 |       4 |        4 |           4 |         4 |        4 |   8 |    9 | EAAAAA   | BGBAAA   | HHHHxx
+       5 |     541 |   1 |    1 |   5 |      5 |       5 |        5 |           5 |         5 |        5 |  10 |   11 | FAAAAA   | VUAAAA   | HHHHxx
+       6 |     978 |   0 |    2 |   6 |      6 |       6 |        6 |           6 |         6 |        6 |  12 |   13 | GAAAAA   | QLBAAA   | OOOOxx
+       7 |     647 |   1 |    3 |   7 |      7 |       7 |        7 |           7 |         7 |        7 |  14 |   15 | HAAAAA   | XYAAAA   | VVVVxx
+       8 |     653 |   0 |    0 |   8 |      8 |       8 |        8 |           8 |         8 |        8 |  16 |   17 | IAAAAA   | DZAAAA   | HHHHxx
+       9 |      49 |   1 |    1 |   9 |      9 |       9 |        9 |           9 |         9 |        9 |  18 |   19 | JAAAAA   | XBAAAA   | HHHHxx
+(10 rows)
+
 --
--- partial btree index
 -- awk '{if($1<20){print $1,$14;}else{next;}}' onek.data | sort +0nr -1
 --
---SELECT onek2.unique1, onek2.stringu1
---    WHERE onek2.unique1 < 20 
---    ORDER BY unique1 using >;
+SELECT onek2.unique1, onek2.stringu1
+    WHERE onek2.unique1 < 20 
+    ORDER BY unique1 using >;
+ unique1 | stringu1 
+---------+----------
+      19 | TAAAAA
+      18 | SAAAAA
+      17 | RAAAAA
+      16 | QAAAAA
+      15 | PAAAAA
+      14 | OAAAAA
+      13 | NAAAAA
+      12 | MAAAAA
+      11 | LAAAAA
+      10 | KAAAAA
+       9 | JAAAAA
+       8 | IAAAAA
+       7 | HAAAAA
+       6 | GAAAAA
+       5 | FAAAAA
+       4 | EAAAAA
+       3 | DAAAAA
+       2 | CAAAAA
+       1 | BAAAAA
+       0 | AAAAAA
+(20 rows)
+
 --
 -- awk '{if($1>980){print $1,$14;}else{next;}}' onek.data | sort +1d -2
 --
---SELECT onek2.unique1, onek2.stringu1
---   WHERE onek2.unique1 > 980
---   ORDER BY stringu1 using <;
-	
+SELECT onek2.unique1, onek2.stringu1
+   WHERE onek2.unique1 > 980;
+ unique1 | stringu1 
+---------+----------
+     981 | TLAAAA
+     982 | ULAAAA
+     983 | VLAAAA
+     984 | WLAAAA
+     985 | XLAAAA
+     986 | YLAAAA
+     987 | ZLAAAA
+     988 | AMAAAA
+     989 | BMAAAA
+     990 | CMAAAA
+     991 | DMAAAA
+     992 | EMAAAA
+     993 | FMAAAA
+     994 | GMAAAA
+     995 | HMAAAA
+     996 | IMAAAA
+     997 | JMAAAA
+     998 | KMAAAA
+     999 | LMAAAA
+(19 rows)
+
 SELECT two, stringu1, ten, string4
    INTO TABLE tmp
    FROM onek;
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index 2ebc7ef3c3a..888edafe750 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -50,20 +50,15 @@ CREATE INDEX bt_f8_index ON bt_f8_heap USING btree (seqno float8_ops);
 
 --
 -- BTREE partial indices
--- partial indices are not supported in PostgreSQL
 --
---CREATE INDEX onek2_u1_prtl ON onek2 USING btree(unique1 int4_ops)
---	where onek2.unique1 < 20 or onek2.unique1 > 980;
+CREATE INDEX onek2_u1_prtl ON onek2 USING btree(unique1 int4_ops)
+	where unique1 < 20 or unique1 > 980;
 
---CREATE INDEX onek2_u2_prtl ON onek2 USING btree(unique2 int4_ops)
---	where onek2.stringu1 < 'B';
+CREATE INDEX onek2_u2_prtl ON onek2 USING btree(unique2 int4_ops)
+	where stringu1 < 'B';
 
--- EXTEND INDEX onek2_u2_prtl where onek2.stringu1 < 'C';
-
--- EXTEND INDEX onek2_u2_prtl;
-
--- CREATE INDEX onek2_stu1_prtl ON onek2 USING btree(stringu1 name_ops)
---	where onek2.stringu1 >= 'J' and onek2.stringu1 < 'K';
+CREATE INDEX onek2_stu1_prtl ON onek2 USING btree(stringu1 name_ops)
+	where onek2.stringu1 >= 'J' and onek2.stringu1 < 'K';
 
 --
 -- RTREE
diff --git a/src/test/regress/sql/portals_p2.sql b/src/test/regress/sql/portals_p2.sql
index c1c92e1cf2b..12bd903e5f1 100644
--- a/src/test/regress/sql/portals_p2.sql
+++ b/src/test/regress/sql/portals_p2.sql
@@ -2,8 +2,6 @@
 -- PORTALS_P2
 --
 
--- EXTEND INDEX onek2_u1_prtl WHERE onek2.unique1 <= 60;
-
 BEGIN;
 
 DECLARE foo13 CURSOR FOR 
diff --git a/src/test/regress/sql/select.sql b/src/test/regress/sql/select.sql
index 42b664eaaee..ee9389dc597 100644
--- a/src/test/regress/sql/select.sql
+++ b/src/test/regress/sql/select.sql
@@ -55,26 +55,32 @@ SELECT onek.unique1, onek.string4
    ORDER BY unique1 using <, string4 using >;
 
 --
--- partial btree index
+-- test partial btree indexes
+--
+-- As of 7.2, planner probably won't pick an indexscan without stats,
+-- so ANALYZE first.
+--
+ANALYZE onek2;
+
+--
 -- awk '{if($1<10){print $0;}else{next;}}' onek.data | sort +0n -1
 --
---SELECT onek2.* WHERE onek2.unique1 < 10;
+SELECT onek2.* WHERE onek2.unique1 < 10;
 
 --
--- partial btree index
 -- awk '{if($1<20){print $1,$14;}else{next;}}' onek.data | sort +0nr -1
 --
---SELECT onek2.unique1, onek2.stringu1
---    WHERE onek2.unique1 < 20 
---    ORDER BY unique1 using >;
+SELECT onek2.unique1, onek2.stringu1
+    WHERE onek2.unique1 < 20 
+    ORDER BY unique1 using >;
 
 --
 -- awk '{if($1>980){print $1,$14;}else{next;}}' onek.data | sort +1d -2
 --
---SELECT onek2.unique1, onek2.stringu1
---   WHERE onek2.unique1 > 980
---   ORDER BY stringu1 using <;
-	
+SELECT onek2.unique1, onek2.stringu1
+   WHERE onek2.unique1 > 980;
+
+
 SELECT two, stringu1, ten, string4
    INTO TABLE tmp
    FROM onek;