Support deferrable uniqueness constraints.

The current implementation fires an AFTER ROW trigger for each tuple that
looks like it might be non-unique according to the index contents at the
time of insertion.  This works well as long as there aren't many conflicts,
but won't scale to massive unique-key reassignments.  Improving that case
is a TODO item.

Dean Rasheed

doc/src/sgml/catalogs.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.202 2009/07/28 02:56:29 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.203 2009/07/29 20:56:17 tgl Exp $ -->
 <!--
  Documentation of the system catalogs, directed toward PostgreSQL developers
  -->
@@ -2675,6 +2675,14 @@
       (<structfield>indisunique</> should always be true when this is true)</entry>
      </row>
 
+     <row>
+      <entry><structfield>indimmediate</structfield></entry>
+      <entry><type>bool</type></entry>
+      <entry></entry>
+      <entry>If true, the uniqueness check is enforced immediately on insertion
+      (<structfield>indisunique</> should always be true when this is true)</entry>
+     </row>
+
      <row>
       <entry><structfield>indisclustered</structfield></entry>
       <entry><type>bool</type></entry>

doc/src/sgml/indexam.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.30 2009/03/24 20:17:08 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.31 2009/07/29 20:56:17 tgl Exp $ -->
 
 <chapter id="indexam">
  <title>Index Access Method Interface Definition</title>
@@ -172,20 +172,32 @@ aminsert (Relation indexRelation,
           bool *isnull,
           ItemPointer heap_tid,
           Relation heapRelation,
-          bool check_uniqueness);
+          IndexUniqueCheck checkUnique);
 </programlisting>
    Insert a new tuple into an existing index.  The <literal>values</> and
    <literal>isnull</> arrays give the key values to be indexed, and
    <literal>heap_tid</> is the TID to be indexed.
    If the access method supports unique indexes (its
    <structname>pg_am</>.<structfield>amcanunique</> flag is true) then
-   <literal>check_uniqueness</> might be true, in which case the access method
+   <literal>checkUnique</> indicates the type of uniqueness check to
-   must verify that there is no conflicting row; this is the only situation in
+   perform.  This varies depending on whether the unique constraint is
-   which the access method normally needs the <literal>heapRelation</>
+   deferrable; see <xref linkend="index-unique-checks"> for details.
-   parameter.  See <xref linkend="index-unique-checks"> for details.
+   Normally the access method only needs the <literal>heapRelation</>
-   The result is TRUE if an index entry was inserted, FALSE if not. (A FALSE
+   parameter when performing uniqueness checking (since then it will have to
-   result does not denote an error condition, but is used for cases such
+   look into the heap to verify tuple liveness).
-   as an index method refusing to index a NULL.)
+  </para>
+
+  <para>
+   The function's boolean result value is significant only when
+   <literal>checkUnique</> is <literal>UNIQUE_CHECK_PARTIAL</>.
+   In this case a TRUE result means the new entry is known unique, whereas
+   FALSE means it might be non-unique (and a deferred uniqueness check must
+   be scheduled).  For other cases a constant FALSE result is recommended.
+  </para>
+
+  <para>
+   Some indexes might not index all tuples.  If the tuple is not to be
+   indexed, <function>aminsert</> should just return without doing anything.
   </para>
 
   <para>
@@ -706,10 +718,10 @@ amrestrpos (IndexScanDesc scan);
   </para>
 
   <para>
-   Furthermore, immediately before raising a uniqueness violation
+   Furthermore, immediately before reporting a uniqueness violation
    according to the above rules, the access method must recheck the
    liveness of the row being inserted.  If it is committed dead then
-   no error should be raised.  (This case cannot occur during the
+   no violation should be reported.  (This case cannot occur during the
    ordinary scenario of inserting a row that's just been created by
    the current transaction.  It can happen during
    <command>CREATE UNIQUE INDEX CONCURRENTLY</>, however.)
@@ -728,8 +740,78 @@ amrestrpos (IndexScanDesc scan);
   </para>
 
   <para>
-   The main limitation of this scheme is that it has no convenient way
+   If the unique constraint is deferrable, there is additional complexity:
-   to support deferred uniqueness checks.
+   we need to be able to insert an index entry for a new row, but defer any
+   uniqueness-violation error until end of statement or even later.  To
+   avoid unnecessary repeat searches of the index, the index access method
+   should do a preliminary uniqueness check during the initial insertion.
+   If this shows that there is definitely no conflicting live tuple, we
+   are done.  Otherwise, we schedule a recheck to occur when it is time to
+   enforce the constraint.  If, at the time of the recheck, both the inserted
+   tuple and some other tuple with the same key are live, then the error
+   must be reported.  (Note that for this purpose, <quote>live</> actually
+   means <quote>any tuple in the index entry's HOT chain is live</>.)
+   To implement this, the <function>aminsert</> function is passed a
+   <literal>checkUnique</> parameter having one of the following values:
+
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>UNIQUE_CHECK_NO</> indicates that no uniqueness checking
+       should be done (this is not a unique index).
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <literal>UNIQUE_CHECK_YES</> indicates that this is a non-deferrable
+       unique index, and the uniqueness check must be done immediately, as
+       described above.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <literal>UNIQUE_CHECK_PARTIAL</> indicates that the unique
+       constraint is deferrable. <productname>PostgreSQL</productname>
+       will use this mode to insert each row's index entry.  The access
+       method must allow duplicate entries into the index, and report any
+       potential duplicates by returning FALSE from <function>aminsert</>.
+       For each row for which FALSE is returned, a deferred recheck will
+       be scheduled.
+      </para>
+
+      <para>
+       The access method must identify any rows which might violate the
+       unique constraint, but it is not an error for it to report false
+       positives. This allows the check to be done without waiting for other
+       transactions to finish; conflicts reported here are not treated as
+       errors and will be rechecked later, by which time they may no longer
+       be conflicts.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <literal>UNIQUE_CHECK_EXISTING</> indicates that this is a deferred
+       recheck of a row that was reported as a potential uniqueness violation.
+       Although this is implemented by calling <function>aminsert</>, the
+       access method must <emphasis>not</> insert a new index entry in this
+       case.  The index entry is already present.  Rather, the access method
+       must check to see if there is another live index entry.  If so, and
+       if the target row is also still live, report error.
+      </para>
+
+      <para>
+       It is recommended that in a <literal>UNIQUE_CHECK_EXISTING</> call,
+       the access method further verify that the target row actually does
+       have an existing entry in the index, and report error if not.  This
+       is a good idea because the index tuple values passed to
+       <function>aminsert</> will have been recomputed.  If the index
+       definition involves functions that are not really immutable, we
+       might be checking the wrong area of the index.  Checking that the
+       target row is found in the recheck verifies that we are scanning
+       for the same tuple values as were used in the original insertion.
+      </para>
+     </listitem>
+    </itemizedlist>
   </para>
 
  </sect1>

doc/src/sgml/ref/create_table.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.114 2009/02/12 13:25:33 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.115 2009/07/29 20:56:17 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -423,11 +423,10 @@ and <replaceable class="PARAMETER">table_constraint</replaceable> is:
       contain values that match values in the referenced
       column(s) of some row of the referenced table.  If <replaceable
       class="parameter">refcolumn</replaceable> is omitted, the
-      primary key of the <replaceable
+      primary key of the <replaceable class="parameter">reftable</replaceable>
-      class="parameter">reftable</replaceable> is used.  The
+      is used.  The referenced columns must be the columns of a non-deferrable
-      referenced columns must be the columns of a unique or primary
+      unique or primary key constraint in the referenced table.  Note that
-      key constraint in the referenced table.  Note that foreign key
+      foreign key constraints cannot be defined between temporary tables and
-      constraints cannot be defined between temporary tables and
       permanent tables.
      </para>
 
@@ -534,9 +533,11 @@ and <replaceable class="PARAMETER">table_constraint</replaceable> is:
       after every command.  Checking of constraints that are
       deferrable can be postponed until the end of the transaction
       (using the <xref linkend="sql-set-constraints" endterm="sql-set-constraints-title"> command).
-      <literal>NOT DEFERRABLE</literal> is the default.  Only foreign
+      <literal>NOT DEFERRABLE</literal> is the default.
-      key constraints currently accept this clause.  All other
+      Currently, only <literal>UNIQUE</>, <literal>PRIMARY KEY</>, and
-      constraint types are not deferrable.
+      <literal>REFERENCES</> (foreign key) constraints accept this
+      clause.  <literal>NOT NULL</> and <literal>CHECK</> constraints are not
+      deferrable.
      </para>
     </listitem>
    </varlistentry>
@@ -1140,6 +1141,23 @@ CREATE TABLE cinemas (
    </para>
   </refsect2>
 
+  <refsect2>
+   <title>Non-deferred Uniqueness Constraints</title>
+
+   <para>
+    When a <literal>UNIQUE</> or <literal>PRIMARY KEY</> constraint is
+    not deferrable, <productname>PostgreSQL</productname> checks for
+    uniqueness immediately whenever a row is inserted or modified.
+    The SQL standard says that uniqueness should be enforced only at
+    the end of the statement; this makes a difference when, for example,
+    a single command updates multiple key values.  To obtain
+    standard-compliant behavior, declare the constraint as
+    <literal>DEFERRABLE</> but not deferred (i.e., <literal>INITIALLY
+    IMMEDIATE</>).  Be aware that this can be significantly slower than
+    immediate uniqueness checking.
+   </para>
+  </refsect2>
+
   <refsect2>
    <title>Column Check Constraints</title>
 

doc/src/sgml/ref/set_constraints.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.16 2008/11/14 10:22:47 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.17 2009/07/29 20:56:17 tgl Exp $ -->
 <refentry id="SQL-SET-CONSTRAINTS">
  <refmeta>
   <refentrytitle id="SQL-SET-CONSTRAINTS-title">SET CONSTRAINTS</refentrytitle>
@@ -66,10 +66,19 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
   </para>
 
   <para>
-   Currently, only foreign key constraints are affected by this
+   Currently, only <literal>UNIQUE</>, <literal>PRIMARY KEY</>, and
-   setting. Check and unique constraints are always effectively
+   <literal>REFERENCES</> (foreign key) constraints are affected by this
-   not deferrable. Triggers that are declared as <quote>constraint
+   setting.  <literal>NOT NULL</> and <literal>CHECK</> constraints are
-   triggers</> are also affected.
+   always checked immediately when a row is inserted or modified
+   (<emphasis>not</> at the end of the statement).
+   Uniqueness constraints that have not been declared <literal>DEFERRABLE</>
+   are also checked immediately.
+  </para>
+
+  <para>
+   The firing of triggers that are declared as <quote>constraint triggers</>
+   is also controlled by this setting &mdash; they fire at the same time
+   that the associated constraint should be checked.
   </para>
  </refsect1>
 
@@ -92,7 +101,7 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
    This command complies with the behavior defined in the SQL
    standard, except for the limitation that, in
    <productname>PostgreSQL</productname>, it only applies to
-   foreign-key constraints.
+   foreign-key and uniqueness constraints.
   </para>
 
  </refsect1>

src/backend/access/gin/gininsert.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.22 2009/06/11 14:48:53 momjian Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.23 2009/07/29 20:56:17 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -415,12 +415,11 @@ gininsert(PG_FUNCTION_ARGS)
 
 #ifdef NOT_USED
 	Relation	heapRel = (Relation) PG_GETARG_POINTER(4);
-	bool		checkUnique = PG_GETARG_BOOL(5);
+	IndexUniqueCheck checkUnique = (IndexUniqueCheck) PG_GETARG_INT32(5);
 #endif
 	GinState	ginstate;
 	MemoryContext oldCtx;
 	MemoryContext insertCtx;
-	uint32		res = 0;
 	int			i;
 
 	insertCtx = AllocSetContextCreate(CurrentMemoryContext,
@@ -440,7 +439,7 @@ gininsert(PG_FUNCTION_ARGS)
 		memset(&collector, 0, sizeof(GinTupleCollector));
 		for (i = 0; i < ginstate.origTupdesc->natts; i++)
 			if (!isnull[i])
-				res += ginHeapTupleFastCollect(index, &ginstate, &collector,
+				ginHeapTupleFastCollect(index, &ginstate, &collector,
 								 (OffsetNumber) (i + 1), values[i], ht_ctid);
 
 		ginHeapTupleFastInsert(index, &ginstate, &collector);
@@ -449,7 +448,7 @@ gininsert(PG_FUNCTION_ARGS)
 	{
 		for (i = 0; i < ginstate.origTupdesc->natts; i++)
 			if (!isnull[i])
-				res += ginHeapTupleInsert(index, &ginstate,
+				ginHeapTupleInsert(index, &ginstate,
 								 (OffsetNumber) (i + 1), values[i], ht_ctid);
 
 	}
@@ -457,5 +456,5 @@ gininsert(PG_FUNCTION_ARGS)
 	MemoryContextSwitchTo(oldCtx);
 	MemoryContextDelete(insertCtx);
 
-	PG_RETURN_BOOL(res > 0);
+	PG_RETURN_BOOL(false);
 }

src/backend/access/gist/gist.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.156 2009/01/01 17:23:34 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.157 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -225,7 +225,7 @@ gistinsert(PG_FUNCTION_ARGS)
 
 #ifdef NOT_USED
 	Relation	heapRel = (Relation) PG_GETARG_POINTER(4);
-	bool		checkUnique = PG_GETARG_BOOL(5);
+	IndexUniqueCheck checkUnique = (IndexUniqueCheck) PG_GETARG_INT32(5);
 #endif
 	IndexTuple	itup;
 	GISTSTATE	giststate;
@@ -248,7 +248,7 @@ gistinsert(PG_FUNCTION_ARGS)
 	MemoryContextSwitchTo(oldCtx);
 	MemoryContextDelete(insertCtx);
 
-	PG_RETURN_BOOL(true);
+	PG_RETURN_BOOL(false);
 }
 
 

src/backend/access/hash/hash.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.112 2009/06/11 14:48:53 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.113 2009/07/29 20:56:18 tgl Exp $
  *
  * NOTES
  *	  This file contains only the public interface routines.
@@ -165,7 +165,7 @@ hashinsert(PG_FUNCTION_ARGS)
 
 #ifdef NOT_USED
 	Relation	heapRel = (Relation) PG_GETARG_POINTER(4);
-	bool		checkUnique = PG_GETARG_BOOL(5);
+	IndexUniqueCheck checkUnique = (IndexUniqueCheck) PG_GETARG_INT32(5);
 #endif
 	IndexTuple	itup;
 
@@ -192,7 +192,7 @@ hashinsert(PG_FUNCTION_ARGS)
 
 	pfree(itup);
 
-	PG_RETURN_BOOL(true);
+	PG_RETURN_BOOL(false);
 }
 
 

src/backend/access/heap/tuptoaster.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.94 2009/07/22 01:21:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.95 2009/07/29 20:56:18 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1229,7 +1229,9 @@ toast_save_datum(Relation rel, Datum value, int options)
 		 */
 		index_insert(toastidx, t_values, t_isnull,
 					 &(toasttup->t_self),
-					 toastrel, toastidx->rd_index->indisunique);
+					 toastrel,
+					 toastidx->rd_index->indisunique ?
+					 UNIQUE_CHECK_YES : UNIQUE_CHECK_NO);
 
 		/*
 		 * Free memory

src/backend/access/index/indexam.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.114 2009/06/11 14:48:54 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.115 2009/07/29 20:56:18 tgl Exp $
  *
  * INTERFACE ROUTINES
  *		index_open		- open an index relation by relation OID
@@ -185,7 +185,7 @@ index_insert(Relation indexRelation,
 			 bool *isnull,
 			 ItemPointer heap_t_ctid,
 			 Relation heapRelation,
-			 bool check_uniqueness)
+			 IndexUniqueCheck checkUnique)
 {
 	FmgrInfo   *procedure;
 
@@ -201,7 +201,7 @@ index_insert(Relation indexRelation,
 									  PointerGetDatum(isnull),
 									  PointerGetDatum(heap_t_ctid),
 									  PointerGetDatum(heapRelation),
-									  BoolGetDatum(check_uniqueness)));
+									  Int32GetDatum((int32) checkUnique)));
 }
 
 /*

src/backend/access/nbtree/nbtinsert.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.170 2009/06/11 14:48:54 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.171 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -49,8 +49,9 @@ typedef struct
 static Buffer _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf);
 
 static TransactionId _bt_check_unique(Relation rel, IndexTuple itup,
-				 Relation heapRel, Buffer buf, OffsetNumber ioffset,
+				 Relation heapRel, Buffer buf, OffsetNumber offset,
-				 ScanKey itup_scankey);
+				 ScanKey itup_scankey,
+				 IndexUniqueCheck checkUnique, bool *is_unique);
 static void _bt_findinsertloc(Relation rel,
 				  Buffer *bufptr,
 				  OffsetNumber *offsetptr,
@@ -85,11 +86,24 @@ static void _bt_vacuum_one_page(Relation rel, Buffer buffer);
  *
  *		This routine is called by the public interface routines, btbuild
  *		and btinsert.  By here, itup is filled in, including the TID.
+ *
+ *		If checkUnique is UNIQUE_CHECK_NO or UNIQUE_CHECK_PARTIAL, this
+ *		will allow duplicates.  Otherwise (UNIQUE_CHECK_YES or
+ *		UNIQUE_CHECK_EXISTING) it will throw error for a duplicate.
+ *		For UNIQUE_CHECK_EXISTING we merely run the duplicate check, and
+ *		don't actually insert.
+ *
+ *		The result value is only significant for UNIQUE_CHECK_PARTIAL:
+ *		it must be TRUE if the entry is known unique, else FALSE.
+ *		(In the current implementation we'll also return TRUE after a
+ *		successful UNIQUE_CHECK_YES or UNIQUE_CHECK_EXISTING call, but
+ *		that's just a coding artifact.)
  */
-void
+bool
 _bt_doinsert(Relation rel, IndexTuple itup,
-			 bool index_is_unique, Relation heapRel)
+			 IndexUniqueCheck checkUnique, Relation heapRel)
 {
+	bool		is_unique = false;
 	int			natts = rel->rd_rel->relnatts;
 	ScanKey		itup_scankey;
 	BTStack		stack;
@@ -134,13 +148,18 @@ top:
 	 *
 	 * If we must wait for another xact, we release the lock while waiting,
 	 * and then must start over completely.
+	 *
+	 * For a partial uniqueness check, we don't wait for the other xact.
+	 * Just let the tuple in and return false for possibly non-unique,
+	 * or true for definitely unique.
 	 */
-	if (index_is_unique)
+	if (checkUnique != UNIQUE_CHECK_NO)
 	{
 		TransactionId xwait;
 
 		offset = _bt_binsrch(rel, buf, natts, itup_scankey, false);
-		xwait = _bt_check_unique(rel, itup, heapRel, buf, offset, itup_scankey);
+		xwait = _bt_check_unique(rel, itup, heapRel, buf, offset, itup_scankey,
+								 checkUnique, &is_unique);
 
 		if (TransactionIdIsValid(xwait))
 		{
@@ -153,13 +172,23 @@ top:
 		}
 	}
 
+	if (checkUnique != UNIQUE_CHECK_EXISTING)
+	{
 		/* do the insertion */
 		_bt_findinsertloc(rel, &buf, &offset, natts, itup_scankey, itup);
 		_bt_insertonpg(rel, buf, stack, itup, offset, false);
+	}
+	else
+	{
+		/* just release the buffer */
+		_bt_relbuf(rel, buf);
+	}
 
 	/* be tidy */
 	_bt_freestack(stack);
 	_bt_freeskey(itup_scankey);
+
+	return is_unique;
 }
 
 /*
@@ -172,10 +201,16 @@ top:
  * Returns InvalidTransactionId if there is no conflict, else an xact ID
  * we must wait for to see if it commits a conflicting tuple.	If an actual
  * conflict is detected, no return --- just ereport().
+ *
+ * However, if checkUnique == UNIQUE_CHECK_PARTIAL, we always return
+ * InvalidTransactionId because we don't want to wait.  In this case we
+ * set *is_unique to false if there is a potential conflict, and the
+ * core code must redo the uniqueness check later.
  */
 static TransactionId
 _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
-				 Buffer buf, OffsetNumber offset, ScanKey itup_scankey)
+				 Buffer buf, OffsetNumber offset, ScanKey itup_scankey,
+				 IndexUniqueCheck checkUnique, bool *is_unique)
 {
 	TupleDesc	itupdesc = RelationGetDescr(rel);
 	int			natts = rel->rd_rel->relnatts;
@@ -184,6 +219,10 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
 	Page		page;
 	BTPageOpaque opaque;
 	Buffer		nbuf = InvalidBuffer;
+	bool		found = false;
+
+	/* Assume unique until we find a duplicate */
+	*is_unique = true;
 
 	InitDirtySnapshot(SnapshotDirty);
 
@@ -240,22 +279,49 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
 				curitup = (IndexTuple) PageGetItem(page, curitemid);
 				htid = curitup->t_tid;
 
+				/*
+				 * If we are doing a recheck, we expect to find the tuple we
+				 * are rechecking.  It's not a duplicate, but we have to keep
+				 * scanning.
+				 */
+				if (checkUnique == UNIQUE_CHECK_EXISTING &&
+					ItemPointerCompare(&htid, &itup->t_tid) == 0)
+				{
+					found = true;
+				}
+
 				/*
 				 * We check the whole HOT-chain to see if there is any tuple
 				 * that satisfies SnapshotDirty.  This is necessary because we
 				 * have just a single index entry for the entire chain.
 				 */
-				if (heap_hot_search(&htid, heapRel, &SnapshotDirty, &all_dead))
+				else if (heap_hot_search(&htid, heapRel, &SnapshotDirty,
+										 &all_dead))
 				{
-					/* it is a duplicate */
+					TransactionId xwait;
-					TransactionId xwait =
+
-					(TransactionIdIsValid(SnapshotDirty.xmin)) ?
+					/*
-					SnapshotDirty.xmin : SnapshotDirty.xmax;
+					 * It is a duplicate. If we are only doing a partial
+					 * check, then don't bother checking if the tuple is
+					 * being updated in another transaction. Just return
+					 * the fact that it is a potential conflict and leave
+					 * the full check till later.
+					 */
+					if (checkUnique == UNIQUE_CHECK_PARTIAL)
+					{
+						if (nbuf != InvalidBuffer)
+							_bt_relbuf(rel, nbuf);
+						*is_unique = false;
+						return InvalidTransactionId;
+					}
 
 					/*
 					 * If this tuple is being updated by other transaction
 					 * then we have to wait for its commit/abort.
 					 */
+					xwait = (TransactionIdIsValid(SnapshotDirty.xmin)) ?
+						SnapshotDirty.xmin : SnapshotDirty.xmax;
+
 					if (TransactionIdIsValid(xwait))
 					{
 						if (nbuf != InvalidBuffer)
@@ -295,6 +361,9 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
 						break;
 					}
 
+					/*
+					 * This is a definite conflict.
+					 */
 					ereport(ERROR,
 							(errcode(ERRCODE_UNIQUE_VIOLATION),
 							 errmsg("duplicate key value violates unique constraint \"%s\"",
@@ -349,6 +418,18 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
 		}
 	}
 
+	/*
+	 * If we are doing a recheck then we should have found the tuple we
+	 * are checking.  Otherwise there's something very wrong --- probably,
+	 * the index is on a non-immutable expression.
+	 */
+	if (checkUnique == UNIQUE_CHECK_EXISTING && !found)
+		ereport(ERROR,
+				(errcode(ERRCODE_INTERNAL_ERROR),
+				 errmsg("failed to re-find tuple within index \"%s\"",
+						RelationGetRelationName(rel)),
+				 errhint("This may be because of a non-immutable index expression.")));
+
 	if (nbuf != InvalidBuffer)
 		_bt_relbuf(rel, nbuf);
 

src/backend/access/nbtree/nbtree.c

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.171 2009/06/11 14:48:54 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.172 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -217,18 +217,19 @@ btinsert(PG_FUNCTION_ARGS)
 	bool	   *isnull = (bool *) PG_GETARG_POINTER(2);
 	ItemPointer ht_ctid = (ItemPointer) PG_GETARG_POINTER(3);
 	Relation	heapRel = (Relation) PG_GETARG_POINTER(4);
-	bool		checkUnique = PG_GETARG_BOOL(5);
+	IndexUniqueCheck checkUnique = (IndexUniqueCheck) PG_GETARG_INT32(5);
+	bool		result;
 	IndexTuple	itup;
 
 	/* generate an index tuple */
 	itup = index_form_tuple(RelationGetDescr(rel), values, isnull);
 	itup->t_tid = *ht_ctid;
 
-	_bt_doinsert(rel, itup, checkUnique, heapRel);
+	result = _bt_doinsert(rel, itup, checkUnique, heapRel);
 
 	pfree(itup);
 
-	PG_RETURN_BOOL(true);
+	PG_RETURN_BOOL(result);
 }
 
 /*

src/backend/bootstrap/bootparse.y

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.96 2009/01/01 17:23:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.97 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -266,7 +266,7 @@ Boot_DeclareIndexStmt:
 								NULL,
 								$10,
 								NULL, NIL,
-								false, false, false,
+								false, false, false, false, false,
 								false, false, true, false, false);
 					do_end();
 				}
@@ -284,7 +284,7 @@ Boot_DeclareUniqueIndexStmt:
 								NULL,
 								$11,
 								NULL, NIL,
-								true, false, false,
+								true, false, false, false, false,
 								false, false, true, false, false);
 					do_end();
 				}

src/backend/catalog/index.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.319 2009/07/28 02:56:29 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.320 2009/07/29 20:56:18 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -40,14 +40,18 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_tablespace.h"
+#include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "commands/tablecmds.h"
+#include "commands/trigger.h"
 #include "executor/executor.h"
 #include "miscadmin.h"
+#include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/clauses.h"
 #include "optimizer/var.h"
+#include "parser/parser.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
 #include "storage/procarray.h"
@@ -87,6 +91,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 					Oid *classOids,
 					int16 *coloptions,
 					bool primary,
+					bool immediate,
 					bool isvalid);
 static void index_update_stats(Relation rel, bool hasindex, bool isprimary,
 				   Oid reltoastidxid, double reltuples);
@@ -372,6 +377,7 @@ UpdateIndexRelation(Oid indexoid,
 					Oid *classOids,
 					int16 *coloptions,
 					bool primary,
+					bool immediate,
 					bool isvalid)
 {
 	int2vector *indkey;
@@ -439,6 +445,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indnatts - 1] = Int16GetDatum(indexInfo->ii_NumIndexAttrs);
 	values[Anum_pg_index_indisunique - 1] = BoolGetDatum(indexInfo->ii_Unique);
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
+	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
 	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
@@ -488,6 +495,8 @@ UpdateIndexRelation(Oid indexoid,
  * reloptions: AM-specific options
  * isprimary: index is a PRIMARY KEY
  * isconstraint: index is owned by a PRIMARY KEY or UNIQUE constraint
+ * deferrable: constraint is DEFERRABLE
+ * initdeferred: constraint is INITIALLY DEFERRED
  * allow_system_table_mods: allow table to be a system catalog
  * skip_build: true to skip the index_build() step for the moment; caller
  *		must do it later (typically via reindex_index())
@@ -509,6 +518,8 @@ index_create(Oid heapRelationId,
 			 Datum reloptions,
 			 bool isprimary,
 			 bool isconstraint,
+			 bool deferrable,
+			 bool initdeferred,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent)
@@ -679,7 +690,9 @@ index_create(Oid heapRelationId,
 	 * ----------------
 	 */
 	UpdateIndexRelation(indexRelationId, heapRelationId, indexInfo,
-						classObjectId, coloptions, isprimary, !concurrent);
+						classObjectId, coloptions, isprimary,
+						!deferrable,
+						!concurrent);
 
 	/*
 	 * Register constraint and dependencies for the index.
@@ -726,8 +739,8 @@ index_create(Oid heapRelationId,
 			conOid = CreateConstraintEntry(indexRelationName,
 										   namespaceId,
 										   constraintType,
-										   false,		/* isDeferrable */
+										   deferrable,
-										   false,		/* isDeferred */
+										   initdeferred,
 										   heapRelationId,
 										   indexInfo->ii_KeyAttrNumbers,
 										   indexInfo->ii_NumIndexAttrs,
@@ -753,6 +766,40 @@ index_create(Oid heapRelationId,
 			referenced.objectSubId = 0;
 
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
+
+			/*
+			 * If the constraint is deferrable, create the deferred uniqueness
+			 * checking trigger.  (The trigger will be given an internal
+			 * dependency on the constraint by CreateTrigger, so there's no
+			 * need to do anything more here.)
+			 */
+			if (deferrable)
+			{
+				RangeVar   *heapRel;
+				CreateTrigStmt *trigger;
+
+				heapRel = makeRangeVar(get_namespace_name(namespaceId),
+									   pstrdup(RelationGetRelationName(heapRelation)),
+									   -1);
+
+				trigger = makeNode(CreateTrigStmt);
+				trigger->trigname = pstrdup(indexRelationName);
+				trigger->relation = heapRel;
+				trigger->funcname = SystemFuncName("unique_key_recheck");
+				trigger->args = NIL;
+				trigger->before = false;
+				trigger->row = true;
+				trigger->events = TRIGGER_TYPE_INSERT | TRIGGER_TYPE_UPDATE;
+				trigger->isconstraint = true;
+				trigger->deferrable = true;
+				trigger->initdeferred = initdeferred;
+				trigger->constrrel = NULL;
+
+				(void) CreateTrigger(trigger, conOid, indexRelationId,
+									 isprimary ? "PK_ConstraintTrigger" :
+									 "Unique_ConstraintTrigger",
+									 false);
+			}
 		}
 		else
 		{
@@ -791,6 +838,10 @@ index_create(Oid heapRelationId,
 
 				recordDependencyOn(&myself, &referenced, DEPENDENCY_AUTO);
 			}
+
+			/* Non-constraint indexes can't be deferrable */
+			Assert(!deferrable);
+			Assert(!initdeferred);
 		}
 
 		/* Store dependency on operator classes */
@@ -823,6 +874,13 @@ index_create(Oid heapRelationId,
 											DEPENDENCY_AUTO);
 		}
 	}
+	else
+	{
+		/* Bootstrap mode - assert we weren't asked for constraint support */
+		Assert(!isconstraint);
+		Assert(!deferrable);
+		Assert(!initdeferred);
+	}
 
 	/*
 	 * Advance the command counter so that we can see the newly-entered
@@ -2190,7 +2248,8 @@ validate_index_heapscan(Relation heapRelation,
 						 isnull,
 						 &rootTuple,
 						 heapRelation,
-						 indexInfo->ii_Unique);
+						 indexInfo->ii_Unique ?
+						 UNIQUE_CHECK_YES : UNIQUE_CHECK_NO);
 
 			state->tups_inserted += 1;
 		}

src/backend/catalog/indexing.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/indexing.c,v 1.117 2009/01/01 17:23:37 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/indexing.c,v 1.118 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -134,7 +134,8 @@ CatalogIndexInsert(CatalogIndexState indstate, HeapTuple heapTuple)
 					 isnull,	/* is-null flags */
 					 &(heapTuple->t_self),		/* tid of heap tuple */
 					 heapRelation,
-					 relationDescs[i]->rd_index->indisunique);
+					 relationDescs[i]->rd_index->indisunique ?
+					 UNIQUE_CHECK_YES : UNIQUE_CHECK_NO);
 	}
 
 	ExecDropSingleTupleTableSlot(slot);

src/backend/catalog/sql_features.txt

@@ -289,7 +289,7 @@ F695	Translation support			NO
 F696	Additional translation documentation			NO	
 F701	Referential update actions			YES	
 F711	ALTER domain			YES	
-F721	Deferrable constraints			NO	foreign keys only
+F721	Deferrable constraints			NO	foreign and unique keys only
 F731	INSERT column privileges			YES	
 F741	Referential MATCH types			NO	no partial match yet
 F751	View CHECK enhancements			NO	

src/backend/catalog/toasting.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.17 2009/06/11 20:46:11 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.18 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -253,7 +253,8 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 							   BTREE_AM_OID,
 							   rel->rd_rel->reltablespace,
 							   classObjectId, coloptions, (Datum) 0,
-							   true, false, true, false, false);
+							   true, false, false, false,
+							   true, false, false);
 
 	/*
 	 * Store the toast table's OID in the parent relation's pg_class row

src/backend/commands/Makefile

@@ -4,7 +4,7 @@
 #    Makefile for backend/commands
 #
 # IDENTIFICATION
-#    $PostgreSQL: pgsql/src/backend/commands/Makefile,v 1.39 2008/12/19 16:25:17 petere Exp $
+#    $PostgreSQL: pgsql/src/backend/commands/Makefile,v 1.40 2009/07/29 20:56:18 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -13,7 +13,7 @@ top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = aggregatecmds.o alter.o analyze.o async.o cluster.o comment.o  \
-	conversioncmds.o copy.o \
+	constraint.o conversioncmds.o copy.o \
 	dbcommands.o define.o discard.o explain.o foreigncmds.o functioncmds.o \
 	indexcmds.o lockcmds.o operatorcmds.o opclasscmds.o \
 	portalcmds.o prepare.o proclang.o \

src/backend/commands/constraint.c

@@ -0,0 +1,166 @@
+/*-------------------------------------------------------------------------
+ *
+ * constraint.c
+ *	  PostgreSQL CONSTRAINT support code.
+ *
+ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/backend/commands/constraint.c,v 1.1 2009/07/29 20:56:18 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/index.h"
+#include "commands/trigger.h"
+#include "executor/executor.h"
+#include "utils/builtins.h"
+#include "utils/tqual.h"
+
+
+/*
+ * unique_key_recheck - trigger function to do a deferred uniqueness check.
+ *
+ * This is invoked as an AFTER ROW trigger for both INSERT and UPDATE,
+ * for any rows recorded as potentially violating a deferrable unique
+ * constraint.
+ *
+ * This may be an end-of-statement check, a commit-time check, or a
+ * check triggered by a SET CONSTRAINTS command.
+ */
+Datum
+unique_key_recheck(PG_FUNCTION_ARGS)
+{
+	TriggerData *trigdata = (TriggerData *) fcinfo->context;
+	const char *funcname = "unique_key_recheck";
+	HeapTuple	new_row;
+	ItemPointerData tmptid;
+	Relation	indexRel;
+	IndexInfo  *indexInfo;
+	EState	   *estate;
+	ExprContext *econtext;
+	TupleTableSlot *slot;
+	Datum		values[INDEX_MAX_KEYS];
+	bool		isnull[INDEX_MAX_KEYS];
+
+	/*
+	 * Make sure this is being called as an AFTER ROW trigger.  Note:
+	 * translatable error strings are shared with ri_triggers.c, so
+	 * resist the temptation to fold the function name into them.
+	 */
+	if (!CALLED_AS_TRIGGER(fcinfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+				 errmsg("function \"%s\" was not called by trigger manager",
+						funcname)));
+
+	if (!TRIGGER_FIRED_AFTER(trigdata->tg_event) ||
+		!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
+		ereport(ERROR,
+				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+				 errmsg("function \"%s\" must be fired AFTER ROW",
+						funcname)));
+
+	/*
+	 * Get the new data that was inserted/updated.
+	 */
+	if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
+		new_row = trigdata->tg_trigtuple;
+	else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
+		new_row = trigdata->tg_newtuple;
+	else
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+				 errmsg("function \"%s\" must be fired for INSERT or UPDATE",
+						funcname)));
+		new_row = NULL;			/* keep compiler quiet */
+	}
+
+	/*
+	 * If the new_row is now dead (ie, inserted and then deleted within our
+	 * transaction), we can skip the check.  However, we have to be careful,
+	 * because this trigger gets queued only in response to index insertions;
+	 * which means it does not get queued for HOT updates.  The row we are
+	 * called for might now be dead, but have a live HOT child, in which case
+	 * we still need to make the uniqueness check.  Therefore we have to use
+	 * heap_hot_search, not just HeapTupleSatisfiesVisibility as is done in
+	 * the comparable test in RI_FKey_check.
+	 *
+	 * This might look like just an optimization, because the index AM will
+	 * make this identical test before throwing an error.  But it's actually
+	 * needed for correctness, because the index AM will also throw an error
+	 * if it doesn't find the index entry for the row.  If the row's dead then
+	 * it's possible the index entry has also been marked dead, and even
+	 * removed.
+	 */
+	tmptid = new_row->t_self;
+	if (!heap_hot_search(&tmptid, trigdata->tg_relation, SnapshotSelf, NULL))
+	{
+		/*
+		 * All rows in the HOT chain are dead, so skip the check.
+		 */
+		return PointerGetDatum(NULL);
+	}
+
+	/*
+	 * Open the index, acquiring a RowExclusiveLock, just as if we were
+	 * going to update it.  (This protects against possible changes of the
+	 * index schema, not against concurrent updates.)
+	 */
+	indexRel = index_open(trigdata->tg_trigger->tgconstrindid,
+						  RowExclusiveLock);
+	indexInfo = BuildIndexInfo(indexRel);
+
+	/*
+	 * The heap tuple must be put into a slot for FormIndexDatum.
+	 */
+	slot = MakeSingleTupleTableSlot(RelationGetDescr(trigdata->tg_relation));
+
+	ExecStoreTuple(new_row, slot, InvalidBuffer, false);
+
+	/*
+	 * Typically the index won't have expressions, but if it does we need
+	 * an EState to evaluate them.
+	 */
+	if (indexInfo->ii_Expressions != NIL)
+	{
+		estate = CreateExecutorState();
+		econtext = GetPerTupleExprContext(estate);
+		econtext->ecxt_scantuple = slot;
+	}
+	else
+		estate = NULL;
+
+	/*
+	 * Form the index values and isnull flags for the index entry that
+	 * we need to check.
+	 *
+	 * Note: if the index uses functions that are not as immutable as they
+	 * are supposed to be, this could produce an index tuple different from
+	 * the original.  The index AM can catch such errors by verifying that
+	 * it finds a matching index entry with the tuple's TID.
+	 */
+	FormIndexDatum(indexInfo, slot, estate, values, isnull);
+
+	/*
+	 * Now do the uniqueness check. This is not a real insert; it is a
+	 * check that the index entry that has already been inserted is unique.
+	 */
+	index_insert(indexRel, values, isnull, &(new_row->t_self),
+				 trigdata->tg_relation, UNIQUE_CHECK_EXISTING);
+
+	/*
+	 * If that worked, then this index entry is unique, and we are done.
+	 */
+	if (estate != NULL)
+		FreeExecutorState(estate);
+
+	ExecDropSingleTupleTableSlot(slot);
+
+	index_close(indexRel, RowExclusiveLock);
+
+	return PointerGetDatum(NULL);
+}

src/backend/commands/copy.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.315 2009/07/25 17:04:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.316 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2130,6 +2130,8 @@ CopyFrom(CopyState cstate)
 
 		if (!skip_tuple)
 		{
+			List *recheckIndexes = NIL;
+
 			/* Place tuple in tuple slot */
 			ExecStoreTuple(tuple, slot, InvalidBuffer, false);
 
@@ -2141,10 +2143,12 @@ CopyFrom(CopyState cstate)
 			heap_insert(cstate->rel, tuple, mycid, hi_options, bistate);
 
 			if (resultRelInfo->ri_NumIndices > 0)
-				ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
+				recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
+													   estate, false);
 
 			/* AFTER ROW INSERT Triggers */
-			ExecARInsertTriggers(estate, resultRelInfo, tuple);
+			ExecARInsertTriggers(estate, resultRelInfo, tuple,
+								 recheckIndexes);
 
 			/*
 			 * We count only tuples not suppressed by a BEFORE INSERT trigger;

src/backend/commands/indexcmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.186 2009/07/16 06:33:42 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.187 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -87,6 +87,8 @@ static bool relationHasPrimaryKey(Relation rel);
  * 'primary': mark the index as a primary key in the catalogs.
  * 'isconstraint': index is for a PRIMARY KEY or UNIQUE constraint,
  *		so build a pg_constraint entry for it.
+ * 'deferrable': constraint is DEFERRABLE.
+ * 'initdeferred': constraint is INITIALLY DEFERRED.
  * 'is_alter_table': this is due to an ALTER rather than a CREATE operation.
  * 'check_rights': check for CREATE rights in the namespace.  (This should
  *		be true except when ALTER is deleting/recreating an index.)
@@ -107,6 +109,8 @@ DefineIndex(RangeVar *heapRelation,
 			bool unique,
 			bool primary,
 			bool isconstraint,
+			bool deferrable,
+			bool initdeferred,
 			bool is_alter_table,
 			bool check_rights,
 			bool skip_build,
@@ -447,7 +451,8 @@ DefineIndex(RangeVar *heapRelation,
 		indexRelationId =
 			index_create(relationId, indexRelationName, indexRelationId,
 					  indexInfo, accessMethodId, tablespaceId, classObjectId,
-						 coloptions, reloptions, primary, isconstraint,
+						 coloptions, reloptions, primary,
+						 isconstraint, deferrable, initdeferred,
 						 allowSystemTableMods, skip_build, concurrent);
 
 		return;					/* We're done, in the standard case */
@@ -465,7 +470,8 @@ DefineIndex(RangeVar *heapRelation,
 	indexRelationId =
 		index_create(relationId, indexRelationName, indexRelationId,
 					 indexInfo, accessMethodId, tablespaceId, classObjectId,
-					 coloptions, reloptions, primary, isconstraint,
+					 coloptions, reloptions, primary,
+					 isconstraint, deferrable, initdeferred,
 					 allowSystemTableMods, true, concurrent);
 
 	/*

src/backend/commands/tablecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.292 2009/07/28 02:56:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.293 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4391,6 +4391,8 @@ ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
 				stmt->unique,
 				stmt->primary,
 				stmt->isconstraint,
+				stmt->deferrable,
+				stmt->initdeferred,
 				true,			/* is_alter_table */
 				check_rights,
 				skip_build,
@@ -4955,6 +4957,17 @@ transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
 		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
 		if (indexStruct->indisprimary)
 		{
+			/*
+			 * Refuse to use a deferrable primary key.  This is per SQL spec,
+			 * and there would be a lot of interesting semantic problems if
+			 * we tried to allow it.
+			 */
+			if (!indexStruct->indimmediate)
+				ereport(ERROR,
+						(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						 errmsg("cannot use a deferrable primary key for referenced table \"%s\"",
+								RelationGetRelationName(pkrel))));
+
 			*indexOid = indexoid;
 			break;
 		}
@@ -5040,11 +5053,12 @@ transformFkeyCheckAttrs(Relation pkrel,
 		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
 
 		/*
-		 * Must have the right number of columns; must be unique and not a
+		 * Must have the right number of columns; must be unique (non
-		 * partial index; forget it if there are any expressions, too
+		 * deferrable) and not a partial index; forget it if there are any
+		 * expressions, too
 		 */
 		if (indexStruct->indnatts == numattrs &&
-			indexStruct->indisunique &&
+			indexStruct->indisunique && indexStruct->indimmediate &&
 			heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
 			heap_attisnull(indexTuple, Anum_pg_index_indexprs))
 		{
@@ -5243,7 +5257,8 @@ CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
 	fk_trigger->constrrel = fkconstraint->pktable;
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid,
+						 "RI_ConstraintTrigger", false);
 
 	/* Make changes-so-far visible */
 	CommandCounterIncrement();
@@ -5322,7 +5337,8 @@ createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 	}
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid,
+						 "RI_ConstraintTrigger", false);
 
 	/* Make changes-so-far visible */
 	CommandCounterIncrement();
@@ -5373,7 +5389,8 @@ createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 	}
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid,
+						 "RI_ConstraintTrigger", false);
 }
 
 /*

src/backend/commands/trigger.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.249 2009/07/28 02:56:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.250 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,7 +63,8 @@ static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
 					Instrumentation *instr,
 					MemoryContext per_tuple_context);
 static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
-					  bool row_trigger, HeapTuple oldtup, HeapTuple newtup);
+					  bool row_trigger, HeapTuple oldtup, HeapTuple newtup,
+					  List *recheckIndexes);
 
 
 /*
@@ -77,6 +78,10 @@ static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
  * indexOid, if nonzero, is the OID of an index associated with the constraint.
  * We do nothing with this except store it into pg_trigger.tgconstrindid.
  *
+ * prefix is NULL for user-created triggers.  For internally generated
+ * constraint triggers, it is a prefix string to use in building the
+ * trigger name.  (stmt->trigname is the constraint name in such cases.)
+ *
  * If checkPermissions is true we require ACL_TRIGGER permissions on the
  * relation.  If not, the caller already checked permissions.  (This is
  * currently redundant with constraintOid being zero, but it's clearer to
@@ -87,7 +92,7 @@ static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
  */
 Oid
 CreateTrigger(CreateTrigStmt *stmt,
-			  Oid constraintOid, Oid indexOid,
+			  Oid constraintOid, Oid indexOid, const char *prefix,
 			  bool checkPermissions)
 {
 	int16		tgtype;
@@ -216,20 +221,20 @@ CreateTrigger(CreateTrigStmt *stmt,
 	trigoid = GetNewOid(tgrel);
 
 	/*
-	 * If trigger is for an RI constraint, the passed-in name is the
+	 * If trigger is for a constraint, stmt->trigname is the constraint
-	 * constraint name; save that and build a unique trigger name to avoid
+	 * name; save that and build a unique trigger name based on the supplied
-	 * collisions with user-selected trigger names.
+	 * prefix, to avoid collisions with user-selected trigger names.
 	 */
-	if (OidIsValid(constraintOid))
+	if (prefix != NULL)
 	{
 		snprintf(constrtrigname, sizeof(constrtrigname),
-				 "RI_ConstraintTrigger_%u", trigoid);
+				 "%s_%u", prefix, trigoid);
 		trigname = constrtrigname;
 		constrname = stmt->trigname;
 	}
 	else if (stmt->isconstraint)
 	{
-		/* constraint trigger: trigger name is also constraint name */
+		/* user constraint trigger: trigger name is also constraint name */
 		trigname = stmt->trigname;
 		constrname = stmt->trigname;
 	}
@@ -1650,7 +1655,7 @@ ExecASInsertTriggers(EState *estate, ResultRelInfo *relinfo)
 
 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_INSERT] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
-							  false, NULL, NULL);
+							  false, NULL, NULL, NIL);
 }
 
 HeapTuple
@@ -1706,13 +1711,13 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 
 void
 ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
-					 HeapTuple trigtuple)
+					 HeapTuple trigtuple, List *recheckIndexes)
 {
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
 	if (trigdesc && trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
-							  true, NULL, trigtuple);
+							  true, NULL, trigtuple, recheckIndexes);
 }
 
 void
@@ -1781,7 +1786,7 @@ ExecASDeleteTriggers(EState *estate, ResultRelInfo *relinfo)
 
 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_DELETE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
-							  false, NULL, NULL);
+							  false, NULL, NULL, NIL);
 }
 
 bool
@@ -1858,7 +1863,7 @@ ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
 												   tupleid, NULL);
 
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
-							  true, trigtuple, NULL);
+							  true, trigtuple, NULL, NIL);
 		heap_freetuple(trigtuple);
 	}
 }
@@ -1929,7 +1934,7 @@ ExecASUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
 
 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_UPDATE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
-							  false, NULL, NULL);
+							  false, NULL, NULL, NIL);
 }
 
 HeapTuple
@@ -1999,7 +2004,8 @@ ExecBRUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
 
 void
 ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
-					 ItemPointer tupleid, HeapTuple newtuple)
+					 ItemPointer tupleid, HeapTuple newtuple,
+					 List *recheckIndexes)
 {
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
 
@@ -2009,7 +2015,7 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
 												   tupleid, NULL);
 
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
-							  true, trigtuple, newtuple);
+							  true, trigtuple, newtuple, recheckIndexes);
 		heap_freetuple(trigtuple);
 	}
 }
@@ -2080,7 +2086,7 @@ ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
 
 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_TRUNCATE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_TRUNCATE,
-							  false, NULL, NULL);
+							  false, NULL, NULL, NIL);
 }
 
 
@@ -3793,15 +3799,18 @@ AfterTriggerPendingOnRel(Oid relid)
 /* ----------
  * AfterTriggerSaveEvent()
  *
- *	Called by ExecA[RS]...Triggers() to add the event to the queue.
+ *	Called by ExecA[RS]...Triggers() to queue up the triggers that should
+ *	be fired for an event.
  *
- *	NOTE: should be called only if we've determined that an event must
+ *	NOTE: this is called whenever there are any triggers associated with
- *	be added to the queue.
+ *	the event (even if they are disabled).  This function decides which
+ *	triggers actually need to be queued.
  * ----------
  */
 static void
 AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
-					  HeapTuple oldtup, HeapTuple newtup)
+					  HeapTuple oldtup, HeapTuple newtup,
+					  List *recheckIndexes)
 {
 	Relation	rel = relinfo->ri_RelationDesc;
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
@@ -3961,6 +3970,17 @@ AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
 			}
 		}
 
+		/*
+		 * If the trigger is a deferred unique constraint check trigger,
+		 * only queue it if the unique constraint was potentially violated,
+		 * which we know from index insertion time.
+		 */
+		if (trigger->tgfoid == F_UNIQUE_KEY_RECHECK)
+		{
+			if (!list_member_oid(recheckIndexes, trigger->tgconstrindid))
+				continue;		/* Uniqueness definitely not violated */
+		}
+
 		/*
 		 * Fill in event structure and add it to the current query's queue.
 		 */

src/backend/executor/execMain.c

@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.326 2009/06/11 20:46:11 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.327 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1753,6 +1753,7 @@ ExecInsert(TupleTableSlot *slot,
 	ResultRelInfo *resultRelInfo;
 	Relation	resultRelationDesc;
 	Oid			newId;
+	List	   *recheckIndexes = NIL;
 
 	/*
 	 * get the heap tuple out of the tuple table slot, making sure we have a
@@ -1834,10 +1835,11 @@ ExecInsert(TupleTableSlot *slot,
 	 * insert index entries for tuple
 	 */
 	if (resultRelInfo->ri_NumIndices > 0)
-		ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
+		recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
+											   estate, false);
 
 	/* AFTER ROW INSERT Triggers */
-	ExecARInsertTriggers(estate, resultRelInfo, tuple);
+	ExecARInsertTriggers(estate, resultRelInfo, tuple, recheckIndexes);
 
 	/* Process RETURNING if present */
 	if (resultRelInfo->ri_projectReturning)
@@ -1999,6 +2001,7 @@ ExecUpdate(TupleTableSlot *slot,
 	HTSU_Result result;
 	ItemPointerData update_ctid;
 	TransactionId update_xmax;
+	List *recheckIndexes = NIL;
 
 	/*
 	 * abort the operation if not running transactions
@@ -2132,10 +2135,12 @@ lreplace:;
 	 * If it's a HOT update, we mustn't insert new index entries.
 	 */
 	if (resultRelInfo->ri_NumIndices > 0 && !HeapTupleIsHeapOnly(tuple))
-		ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
+		recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
+											   estate, false);
 
 	/* AFTER ROW UPDATE Triggers */
-	ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
+	ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple,
+						 recheckIndexes);
 
 	/* Process RETURNING if present */
 	if (resultRelInfo->ri_projectReturning)

src/backend/executor/execUtils.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.160 2009/07/18 19:15:41 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.161 2009/07/29 20:56:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1033,17 +1033,22 @@ ExecCloseIndices(ResultRelInfo *resultRelInfo)
  *		doesn't provide the functionality needed by the
  *		executor.. -cim 9/27/89
  *
+ *		This returns a list of OIDs for any unique indexes
+ *		whose constraint check was deferred and which had
+ *		potential (unconfirmed) conflicts.
+ *
  *		CAUTION: this must not be called for a HOT update.
  *		We can't defend against that here for lack of info.
  *		Should we change the API to make it safer?
  * ----------------------------------------------------------------
  */
-void
+List *
 ExecInsertIndexTuples(TupleTableSlot *slot,
 					  ItemPointer tupleid,
 					  EState *estate,
-					  bool is_vacuum)
+					  bool is_vacuum_full)
 {
+	List	   *result = NIL;
 	ResultRelInfo *resultRelInfo;
 	int			i;
 	int			numIndices;
@@ -1077,9 +1082,12 @@ ExecInsertIndexTuples(TupleTableSlot *slot,
 	 */
 	for (i = 0; i < numIndices; i++)
 	{
+		Relation	indexRelation = relationDescs[i];
 		IndexInfo  *indexInfo;
+		IndexUniqueCheck checkUnique;
+		bool		isUnique;
 
-		if (relationDescs[i] == NULL)
+		if (indexRelation == NULL)
 			continue;
 
 		indexInfo = indexInfoArray[i];
@@ -1122,22 +1130,50 @@ ExecInsertIndexTuples(TupleTableSlot *slot,
 					   isnull);
 
 		/*
-		 * The index AM does the rest.	Note we suppress unique-index checks
+		 * The index AM does the rest, including uniqueness checking.
-		 * if we are being called from VACUUM, since VACUUM may need to move
+		 *
-		 * dead tuples that have the same keys as live ones.
+		 * For an immediate-mode unique index, we just tell the index AM to
+		 * throw error if not unique.
+		 *
+		 * For a deferrable unique index, we tell the index AM to just detect
+		 * possible non-uniqueness, and we add the index OID to the result
+		 * list if further checking is needed.
+		 *
+		 * Special hack: we suppress unique-index checks if we are being
+		 * called from VACUUM FULL, since VACUUM FULL may need to move dead
+		 * tuples that have the same keys as live ones.
 		 */
-		index_insert(relationDescs[i],	/* index relation */
+		if (is_vacuum_full || !indexRelation->rd_index->indisunique)
+			checkUnique = UNIQUE_CHECK_NO;
+		else if (indexRelation->rd_index->indimmediate)
+			checkUnique = UNIQUE_CHECK_YES;
+		else
+			checkUnique = UNIQUE_CHECK_PARTIAL;
+
+		isUnique =
+			index_insert(indexRelation,	/* index relation */
 						 values,		/* array of index Datums */
 						 isnull,		/* null flags */
 						 tupleid,		/* tid of heap tuple */
-					 heapRelation,
+						 heapRelation,	/* heap relation */
-					 relationDescs[i]->rd_index->indisunique && !is_vacuum);
+						 checkUnique);	/* type of uniqueness check to do */
+
+		if (checkUnique == UNIQUE_CHECK_PARTIAL && !isUnique)
+		{
+			/*
+			 * The tuple potentially violates the uniqueness constraint,
+			 * so make a note of the index so that we can re-check it later.
+			 */
+			result = lappend_oid(result, RelationGetRelid(indexRelation));
+		}
 
 		/*
 		 * keep track of index inserts for debugging
 		 */
 		IncrIndexInserted();
 	}
+
+	return result;
 }
 
 /*

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.435 2009/07/26 23:34:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.436 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2091,6 +2091,8 @@ _copyConstraint(Constraint *from)
 	COPY_NODE_FIELD(keys);
 	COPY_NODE_FIELD(options);
 	COPY_STRING_FIELD(indexspace);
+	COPY_SCALAR_FIELD(deferrable);
+	COPY_SCALAR_FIELD(initdeferred);
 
 	return newnode;
 }
@@ -2510,6 +2512,8 @@ _copyIndexStmt(IndexStmt *from)
 	COPY_SCALAR_FIELD(unique);
 	COPY_SCALAR_FIELD(primary);
 	COPY_SCALAR_FIELD(isconstraint);
+	COPY_SCALAR_FIELD(deferrable);
+	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
 
 	return newnode;

src/backend/nodes/equalfuncs.c

@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.358 2009/07/26 23:34:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.359 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1160,6 +1160,8 @@ _equalIndexStmt(IndexStmt *a, IndexStmt *b)
 	COMPARE_SCALAR_FIELD(unique);
 	COMPARE_SCALAR_FIELD(primary);
 	COMPARE_SCALAR_FIELD(isconstraint);
+	COMPARE_SCALAR_FIELD(deferrable);
+	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
 
 	return true;
@@ -2068,6 +2070,8 @@ _equalConstraint(Constraint *a, Constraint *b)
 	COMPARE_NODE_FIELD(keys);
 	COMPARE_NODE_FIELD(options);
 	COMPARE_STRING_FIELD(indexspace);
+	COMPARE_SCALAR_FIELD(deferrable);
+	COMPARE_SCALAR_FIELD(initdeferred);
 
 	return true;
 }

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.361 2009/07/16 06:33:42 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.362 2009/07/29 20:56:19 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1734,6 +1734,8 @@ _outIndexStmt(StringInfo str, IndexStmt *node)
 	WRITE_BOOL_FIELD(unique);
 	WRITE_BOOL_FIELD(primary);
 	WRITE_BOOL_FIELD(isconstraint);
+	WRITE_BOOL_FIELD(deferrable);
+	WRITE_BOOL_FIELD(initdeferred);
 	WRITE_BOOL_FIELD(concurrent);
 }
 
@@ -2285,6 +2287,8 @@ _outConstraint(StringInfo str, Constraint *node)
 			WRITE_NODE_FIELD(keys);
 			WRITE_NODE_FIELD(options);
 			WRITE_STRING_FIELD(indexspace);
+			WRITE_BOOL_FIELD(deferrable);
+			WRITE_BOOL_FIELD(initdeferred);
 			break;
 
 		case CONSTR_UNIQUE:
@@ -2292,6 +2296,8 @@ _outConstraint(StringInfo str, Constraint *node)
 			WRITE_NODE_FIELD(keys);
 			WRITE_NODE_FIELD(options);
 			WRITE_STRING_FIELD(indexspace);
+			WRITE_BOOL_FIELD(deferrable);
+			WRITE_BOOL_FIELD(initdeferred);
 			break;
 
 		case CONSTR_CHECK:

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.673 2009/07/26 23:34:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.674 2009/07/29 20:56:19 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -2220,6 +2220,8 @@ ColConstraintElem:
 					n->cooked_expr = NULL;
 					n->keys = NULL;
 					n->indexspace = NULL;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| NULL_P
@@ -2231,6 +2233,8 @@ ColConstraintElem:
 					n->cooked_expr = NULL;
 					n->keys = NULL;
 					n->indexspace = NULL;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| UNIQUE opt_definition OptConsTableSpace
@@ -2243,6 +2247,8 @@ ColConstraintElem:
 					n->keys = NULL;
 					n->options = $2;
 					n->indexspace = $3;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| PRIMARY KEY opt_definition OptConsTableSpace
@@ -2255,6 +2261,8 @@ ColConstraintElem:
 					n->keys = NULL;
 					n->options = $3;
 					n->indexspace = $4;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| CHECK '(' a_expr ')'
@@ -2266,6 +2274,8 @@ ColConstraintElem:
 					n->cooked_expr = NULL;
 					n->keys = NULL;
 					n->indexspace = NULL;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| DEFAULT b_expr
@@ -2277,6 +2287,8 @@ ColConstraintElem:
 					n->cooked_expr = NULL;
 					n->keys = NULL;
 					n->indexspace = NULL;
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| REFERENCES qualified_name opt_column_list key_match key_actions
@@ -2398,7 +2410,7 @@ TableConstraint:
 		;
 
 ConstraintElem:
-			CHECK '(' a_expr ')'
+			CHECK '(' a_expr ')' ConstraintAttributeSpec
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_CHECK;
@@ -2406,9 +2418,17 @@ ConstraintElem:
 					n->raw_expr = $3;
 					n->cooked_expr = NULL;
 					n->indexspace = NULL;
+					if ($5 != 0)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("CHECK constraints cannot be deferred"),
+								 parser_errposition(@5)));
+					n->deferrable = FALSE;
+					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| UNIQUE '(' columnList ')' opt_definition OptConsTableSpace
+				ConstraintAttributeSpec
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_UNIQUE;
@@ -2418,9 +2438,12 @@ ConstraintElem:
 					n->keys = $3;
 					n->options = $5;
 					n->indexspace = $6;
+					n->deferrable = ($7 & 1) != 0;
+					n->initdeferred = ($7 & 2) != 0;
 					$$ = (Node *)n;
 				}
 			| PRIMARY KEY '(' columnList ')' opt_definition OptConsTableSpace
+				ConstraintAttributeSpec
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_PRIMARY;
@@ -2430,6 +2453,8 @@ ConstraintElem:
 					n->keys = $4;
 					n->options = $6;
 					n->indexspace = $7;
+					n->deferrable = ($8 & 1) != 0;
+					n->initdeferred = ($8 & 2) != 0;
 					$$ = (Node *)n;
 				}
 			| FOREIGN KEY '(' columnList ')' REFERENCES qualified_name

src/backend/parser/parse_utilcmd.c

@@ -19,7 +19,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.23 2009/07/16 06:33:43 petere Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.24 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,6 +33,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_constraint.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_type.h"
 #include "commands/defrem.h"
@@ -801,15 +802,38 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 
 	/*
 	 * If the index is marked PRIMARY, it's certainly from a constraint; else,
-	 * if it's not marked UNIQUE, it certainly isn't; else, we have to search
+	 * if it's not marked UNIQUE, it certainly isn't.  If it is or might be
-	 * pg_depend to see if there's an associated unique constraint.
+	 * from a constraint, we have to fetch the constraint to check for
+	 * deferrability attributes.
 	 */
-	if (index->primary)
+	if (index->primary || index->unique)
+	{
+		Oid		constraintId = get_index_constraint(source_relid);
+
+		if (OidIsValid(constraintId))
+		{
+			HeapTuple	ht_constr;
+			Form_pg_constraint conrec;
+
+			ht_constr = SearchSysCache(CONSTROID,
+									   ObjectIdGetDatum(constraintId),
+									   0, 0, 0);
+			if (!HeapTupleIsValid(ht_constr))
+				elog(ERROR, "cache lookup failed for constraint %u",
+					 constraintId);
+			conrec = (Form_pg_constraint) GETSTRUCT(ht_constr);
+
 			index->isconstraint = true;
-	else if (!index->unique)
+			index->deferrable = conrec->condeferrable;
-		index->isconstraint = false;
+			index->initdeferred = conrec->condeferred;
+
+			ReleaseSysCache(ht_constr);
+		}
 		else
-		index->isconstraint = OidIsValid(get_index_constraint(source_relid));
+			index->isconstraint = false;
+	}
+	else
+		index->isconstraint = false;
 
 	/* Get the index expressions, if any */
 	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
@@ -1039,7 +1063,9 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 
 			if (equal(index->indexParams, priorindex->indexParams) &&
 				equal(index->whereClause, priorindex->whereClause) &&
-				strcmp(index->accessMethod, priorindex->accessMethod) == 0)
+				strcmp(index->accessMethod, priorindex->accessMethod) == 0 &&
+				index->deferrable == priorindex->deferrable &&
+				index->initdeferred == priorindex->initdeferred)
 			{
 				priorindex->unique |= index->unique;
 
@@ -1092,6 +1118,8 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 		 */
 	}
 	index->isconstraint = true;
+	index->deferrable = constraint->deferrable;
+	index->initdeferred = constraint->initdeferred;
 
 	if (constraint->name != NULL)
 		index->idxname = pstrdup(constraint->name);
@@ -1853,8 +1881,9 @@ transformAlterTableStmt(AlterTableStmt *stmt, const char *queryString)
  * to attach constraint attributes to their primary constraint nodes
  * and detect inconsistent/misplaced constraint attributes.
  *
- * NOTE: currently, attributes are only supported for FOREIGN KEY primary
+ * NOTE: currently, attributes are only supported for FOREIGN KEY, UNIQUE,
- * constraints, but someday they ought to be supported for other constraints.
+ * and PRIMARY KEY constraints, but someday they ought to be supported
+ * for other constraint types.
  */
 static void
 transformConstraintAttrs(List *constraintList)
@@ -1864,6 +1893,13 @@ transformConstraintAttrs(List *constraintList)
 	bool		saw_initially = false;
 	ListCell   *clist;
 
+#define SUPPORTS_ATTRS(node)								\
+	((node) != NULL &&										\
+	 (IsA((node), FkConstraint) ||							\
+	  (IsA((node), Constraint) &&							\
+	   (((Constraint *) (node))->contype == CONSTR_PRIMARY || \
+		((Constraint *) (node))->contype == CONSTR_UNIQUE))))
+
 	foreach(clist, constraintList)
 	{
 		Node	   *node = lfirst(clist);
@@ -1882,8 +1918,7 @@ transformConstraintAttrs(List *constraintList)
 			switch (con->contype)
 			{
 				case CONSTR_ATTR_DEFERRABLE:
-					if (lastprimarynode == NULL ||
+					if (!SUPPORTS_ATTRS(lastprimarynode))
-						!IsA(lastprimarynode, FkConstraint))
 						ereport(ERROR,
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("misplaced DEFERRABLE clause")));
@@ -1892,11 +1927,14 @@ transformConstraintAttrs(List *constraintList)
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed")));
 					saw_deferrability = true;
+					if (IsA(lastprimarynode, FkConstraint))
 						((FkConstraint *) lastprimarynode)->deferrable = true;
+					else
+						((Constraint *) lastprimarynode)->deferrable = true;
 					break;
+
 				case CONSTR_ATTR_NOT_DEFERRABLE:
-					if (lastprimarynode == NULL ||
+					if (!SUPPORTS_ATTRS(lastprimarynode))
-						!IsA(lastprimarynode, FkConstraint))
 						ereport(ERROR,
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("misplaced NOT DEFERRABLE clause")));
@@ -1905,16 +1943,28 @@ transformConstraintAttrs(List *constraintList)
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed")));
 					saw_deferrability = true;
+					if (IsA(lastprimarynode, FkConstraint))
+					{
 						((FkConstraint *) lastprimarynode)->deferrable = false;
 						if (saw_initially &&
 							((FkConstraint *) lastprimarynode)->initdeferred)
 							ereport(ERROR,
 									(errcode(ERRCODE_SYNTAX_ERROR),
 									 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
+					}
+					else
+					{
+						((Constraint *) lastprimarynode)->deferrable = false;
+						if (saw_initially &&
+							((Constraint *) lastprimarynode)->initdeferred)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
+					}
 					break;
+
 				case CONSTR_ATTR_DEFERRED:
-					if (lastprimarynode == NULL ||
+					if (!SUPPORTS_ATTRS(lastprimarynode))
-						!IsA(lastprimarynode, FkConstraint))
 						ereport(ERROR,
 								(errcode(ERRCODE_SYNTAX_ERROR),
 							 errmsg("misplaced INITIALLY DEFERRED clause")));
@@ -1923,21 +1973,36 @@ transformConstraintAttrs(List *constraintList)
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed")));
 					saw_initially = true;
-					((FkConstraint *) lastprimarynode)->initdeferred = true;
 
 					/*
 					 * If only INITIALLY DEFERRED appears, assume DEFERRABLE
 					 */
+					if (IsA(lastprimarynode, FkConstraint))
+					{
+						((FkConstraint *) lastprimarynode)->initdeferred = true;
+
 						if (!saw_deferrability)
 							((FkConstraint *) lastprimarynode)->deferrable = true;
 						else if (!((FkConstraint *) lastprimarynode)->deferrable)
 							ereport(ERROR,
 									(errcode(ERRCODE_SYNTAX_ERROR),
 									 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
+					}
+					else
+					{
+						((Constraint *) lastprimarynode)->initdeferred = true;
+
+						if (!saw_deferrability)
+							((Constraint *) lastprimarynode)->deferrable = true;
+						else if (!((Constraint *) lastprimarynode)->deferrable)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
+					}
 					break;
+
 				case CONSTR_ATTR_IMMEDIATE:
-					if (lastprimarynode == NULL ||
+					if (!SUPPORTS_ATTRS(lastprimarynode))
-						!IsA(lastprimarynode, FkConstraint))
 						ereport(ERROR,
 								(errcode(ERRCODE_SYNTAX_ERROR),
 							errmsg("misplaced INITIALLY IMMEDIATE clause")));
@@ -1946,8 +2011,12 @@ transformConstraintAttrs(List *constraintList)
 								(errcode(ERRCODE_SYNTAX_ERROR),
 								 errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed")));
 					saw_initially = true;
+					if (IsA(lastprimarynode, FkConstraint))
 						((FkConstraint *) lastprimarynode)->initdeferred = false;
+					else
+						((Constraint *) lastprimarynode)->initdeferred = false;
 					break;
+
 				default:
 					/* Otherwise it's not an attribute */
 					lastprimarynode = node;

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.312 2009/07/28 02:56:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.313 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -795,6 +795,8 @@ ProcessUtility(Node *parsetree,
 							stmt->unique,
 							stmt->primary,
 							stmt->isconstraint,
+							stmt->deferrable,
+							stmt->initdeferred,
 							false,		/* is_alter_table */
 							true,		/* check_rights */
 							false,		/* skip_build */
@@ -929,7 +931,7 @@ ProcessUtility(Node *parsetree,
 
 		case T_CreateTrigStmt:
 			CreateTrigger((CreateTrigStmt *) parsetree,
-						  InvalidOid, InvalidOid, true);
+						  InvalidOid, InvalidOid, NULL, true);
 			break;
 
 		case T_DropPropertyStmt:

src/backend/utils/adt/ruleutils.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.304 2009/07/24 21:08:42 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.305 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1044,11 +1044,6 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 				if (string)
 					appendStringInfo(&buf, " ON DELETE %s", string);
 
-				if (conForm->condeferrable)
-					appendStringInfo(&buf, " DEFERRABLE");
-				if (conForm->condeferred)
-					appendStringInfo(&buf, " INITIALLY DEFERRED");
-
 				break;
 			}
 		case CONSTRAINT_PRIMARY:
@@ -1150,6 +1145,11 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 			break;
 	}
 
+	if (conForm->condeferrable)
+		appendStringInfo(&buf, " DEFERRABLE");
+	if (conForm->condeferred)
+		appendStringInfo(&buf, " INITIALLY DEFERRED");
+
 	/* Cleanup */
 	ReleaseSysCache(tup);
 

src/backend/utils/cache/relcache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.287 2009/06/11 14:49:05 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.288 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2938,7 +2938,7 @@ RelationGetIndexList(Relation relation)
 
 		/* Check to see if it is a unique, non-partial btree index on OID */
 		if (index->indnatts == 1 &&
-			index->indisunique &&
+			index->indisunique && index->indimmediate &&
 			index->indkey.values[0] == ObjectIdAttributeNumber &&
 			index->indclass.values[0] == OID_BTREE_OPS_OID &&
 			heap_attisnull(htup, Anum_pg_index_indpred))

src/bin/pg_dump/pg_dump.c

@@ -12,7 +12,7 @@
  *	by PostgreSQL
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.542 2009/07/23 22:59:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.543 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3655,6 +3655,8 @@ getIndexes(TableInfo tblinfo[], int numTables)
 				i_indisclustered,
 				i_contype,
 				i_conname,
+				i_condeferrable,
+				i_condeferred,
 				i_contableoid,
 				i_conoid,
 				i_tablespace,
@@ -3696,6 +3698,7 @@ getIndexes(TableInfo tblinfo[], int numTables)
 							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "c.contype, c.conname, "
+							  "c.condeferrable, c.condeferred, "
 							  "c.tableoid AS contableoid, "
 							  "c.oid AS conoid, "
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
@@ -3722,6 +3725,7 @@ getIndexes(TableInfo tblinfo[], int numTables)
 							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "c.contype, c.conname, "
+							  "c.condeferrable, c.condeferred, "
 							  "c.tableoid AS contableoid, "
 							  "c.oid AS conoid, "
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
@@ -3748,6 +3752,7 @@ getIndexes(TableInfo tblinfo[], int numTables)
 							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "c.contype, c.conname, "
+							  "c.condeferrable, c.condeferred, "
 							  "c.tableoid AS contableoid, "
 							  "c.oid AS conoid, "
 							  "NULL AS tablespace, "
@@ -3776,6 +3781,8 @@ getIndexes(TableInfo tblinfo[], int numTables)
 							  "CASE WHEN i.indisprimary THEN 'p'::char "
 							  "ELSE '0'::char END AS contype, "
 							  "t.relname AS conname, "
+							  "false AS condeferrable, "
+							  "false AS condeferred, "
 							  "0::oid AS contableoid, "
 							  "t.oid AS conoid, "
 							  "NULL AS tablespace, "
@@ -3799,6 +3806,8 @@ getIndexes(TableInfo tblinfo[], int numTables)
 							  "CASE WHEN i.indisprimary THEN 'p'::char "
 							  "ELSE '0'::char END AS contype, "
 							  "t.relname AS conname, "
+							  "false AS condeferrable, "
+							  "false AS condeferred, "
 							  "0::oid AS contableoid, "
 							  "t.oid AS conoid, "
 							  "NULL AS tablespace, "
@@ -3824,6 +3833,8 @@ getIndexes(TableInfo tblinfo[], int numTables)
 		i_indisclustered = PQfnumber(res, "indisclustered");
 		i_contype = PQfnumber(res, "contype");
 		i_conname = PQfnumber(res, "conname");
+		i_condeferrable = PQfnumber(res, "condeferrable");
+		i_condeferred = PQfnumber(res, "condeferred");
 		i_contableoid = PQfnumber(res, "contableoid");
 		i_conoid = PQfnumber(res, "conoid");
 		i_tablespace = PQfnumber(res, "tablespace");
@@ -3884,6 +3895,8 @@ getIndexes(TableInfo tblinfo[], int numTables)
 				constrinfo[j].condef = NULL;
 				constrinfo[j].confrelid = InvalidOid;
 				constrinfo[j].conindex = indxinfo[j].dobj.dumpId;
+				constrinfo[j].condeferrable = *(PQgetvalue(res, j, i_condeferrable)) == 't';
+				constrinfo[j].condeferred = *(PQgetvalue(res, j, i_condeferred)) == 't';
 				constrinfo[j].conislocal = true;
 				constrinfo[j].separate = true;
 
@@ -3988,6 +4001,8 @@ getConstraints(TableInfo tblinfo[], int numTables)
 			constrinfo[j].condef = strdup(PQgetvalue(res, j, i_condef));
 			constrinfo[j].confrelid = atooid(PQgetvalue(res, j, i_confrelid));
 			constrinfo[j].conindex = 0;
+			constrinfo[j].condeferrable = false;
+			constrinfo[j].condeferred = false;
 			constrinfo[j].conislocal = true;
 			constrinfo[j].separate = true;
 		}
@@ -4072,6 +4087,8 @@ getDomainConstraints(TypeInfo *tinfo)
 		constrinfo[i].condef = strdup(PQgetvalue(res, i, i_consrc));
 		constrinfo[i].confrelid = InvalidOid;
 		constrinfo[i].conindex = 0;
+		constrinfo[i].condeferrable = false;
+		constrinfo[i].condeferred = false;
 		constrinfo[i].conislocal = true;
 		constrinfo[i].separate = false;
 
@@ -5071,6 +5088,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 				constrs[j].condef = strdup(PQgetvalue(res, j, 3));
 				constrs[j].confrelid = InvalidOid;
 				constrs[j].conindex = 0;
+				constrs[j].condeferrable = false;
+				constrs[j].condeferred = false;
 				constrs[j].conislocal = (PQgetvalue(res, j, 4)[0] == 't');
 				constrs[j].separate = false;
 
@@ -10454,6 +10473,13 @@ dumpConstraint(Archive *fout, ConstraintInfo *coninfo)
 		if (indxinfo->options && strlen(indxinfo->options) > 0)
 			appendPQExpBuffer(q, " WITH (%s)", indxinfo->options);
 
+		if (coninfo->condeferrable)
+		{
+			appendPQExpBuffer(q, " DEFERRABLE");
+			if (coninfo->condeferred)
+				appendPQExpBuffer(q, " INITIALLY DEFERRED");
+		}
+
 		appendPQExpBuffer(q, ";\n");
 
 		/* If the index is clustered, we need to record that. */

src/bin/pg_dump/pg_dump.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.h,v 1.154 2009/06/11 14:49:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.h,v 1.155 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -332,6 +332,9 @@ typedef struct _triggerInfo
  * struct ConstraintInfo is used for all constraint types.	However we
  * use a different objType for foreign key constraints, to make it easier
  * to sort them the way we want.
+ *
+ * Note: condeferrable and condeferred are currently only valid for
+ * unique/primary-key constraints.  Otherwise that info is in condef.
  */
 typedef struct _constraintInfo
 {
@@ -342,6 +345,8 @@ typedef struct _constraintInfo
 	char	   *condef;			/* definition, if CHECK or FOREIGN KEY */
 	Oid			confrelid;		/* referenced table, if FOREIGN KEY */
 	DumpId		conindex;		/* identifies associated index if any */
+	bool		condeferrable;	/* TRUE if constraint is DEFERRABLE */
+	bool		condeferred;	/* TRUE if constraint is INITIALLY DEFERRED */
 	bool		conislocal;		/* TRUE if constraint has local definition */
 	bool		separate;		/* TRUE if must dump as separate item */
 } ConstraintInfo;

src/bin/psql/describe.c

@@ -8,7 +8,7 @@
  *
  * Copyright (c) 2000-2009, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.225 2009/07/20 03:46:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.226 2009/07/29 20:56:19 tgl Exp $
  */
 #include "postgres_fe.h"
 
@@ -1321,11 +1321,32 @@ describeOneTableDetails(const char *schemaname,
 		printfPQExpBuffer(&buf,
 				 "SELECT i.indisunique, i.indisprimary, i.indisclustered, ");
 		if (pset.sversion >= 80200)
-			appendPQExpBuffer(&buf, "i.indisvalid, ");
+			appendPQExpBuffer(&buf, "i.indisvalid,\n");
 		else
-			appendPQExpBuffer(&buf, "true as indisvalid, ");
+			appendPQExpBuffer(&buf, "true AS indisvalid,\n");
-		appendPQExpBuffer(&buf, "a.amname, c2.relname,\n"
+		if (pset.sversion >= 80500)
-					"  pg_catalog.pg_get_expr(i.indpred, i.indrelid, true)\n"
+			appendPQExpBuffer(&buf,
+							  "  (NOT i.indimmediate) AND "
+							  "EXISTS (SELECT 1 FROM pg_catalog.pg_depend d, "
+							  "pg_catalog.pg_constraint con WHERE "
+							  "d.classid = 'pg_catalog.pg_class'::pg_catalog.regclass AND "
+							  "d.objid = i.indexrelid AND "
+							  "d.refclassid = 'pg_catalog.pg_constraint'::pg_catalog.regclass AND "
+							  "d.refobjid = con.oid AND d.deptype = 'i' AND "
+							  "con.condeferrable) AS condeferrable,\n"
+							  "  (NOT i.indimmediate) AND "
+							  "EXISTS (SELECT 1 FROM pg_catalog.pg_depend d, "
+							  "pg_catalog.pg_constraint con WHERE "
+							  "d.classid = 'pg_catalog.pg_class'::pg_catalog.regclass AND "
+							  "d.objid = i.indexrelid AND "
+							  "d.refclassid = 'pg_catalog.pg_constraint'::pg_catalog.regclass AND "
+							  "d.refobjid = con.oid AND d.deptype = 'i' AND "
+							  "con.condeferred) AS condeferred,\n");
+		else
+			appendPQExpBuffer(&buf,
+						"  false AS condeferrable, false AS condeferred,\n");
+		appendPQExpBuffer(&buf, "  a.amname, c2.relname, "
+						  "pg_catalog.pg_get_expr(i.indpred, i.indrelid, true)\n"
 						  "FROM pg_catalog.pg_index i, pg_catalog.pg_class c, pg_catalog.pg_class c2, pg_catalog.pg_am a\n"
 		  "WHERE i.indexrelid = c.oid AND c.oid = '%s' AND c.relam = a.oid\n"
 						  "AND i.indrelid = c2.oid",
@@ -1345,9 +1366,11 @@ describeOneTableDetails(const char *schemaname,
 			char	   *indisprimary = PQgetvalue(result, 0, 1);
 			char	   *indisclustered = PQgetvalue(result, 0, 2);
 			char	   *indisvalid = PQgetvalue(result, 0, 3);
-			char	   *indamname = PQgetvalue(result, 0, 4);
+			char	   *deferrable = PQgetvalue(result, 0, 4);
-			char	   *indtable = PQgetvalue(result, 0, 5);
+			char	   *deferred = PQgetvalue(result, 0, 5);
-			char	   *indpred = PQgetvalue(result, 0, 6);
+			char	   *indamname = PQgetvalue(result, 0, 6);
+			char	   *indtable = PQgetvalue(result, 0, 7);
+			char	   *indpred = PQgetvalue(result, 0, 8);
 
 			if (strcmp(indisprimary, "t") == 0)
 				printfPQExpBuffer(&tmpbuf, _("primary key, "));
@@ -1370,6 +1393,12 @@ describeOneTableDetails(const char *schemaname,
 			if (strcmp(indisvalid, "t") != 0)
 				appendPQExpBuffer(&tmpbuf, _(", invalid"));
 
+			if (strcmp(deferrable, "t") == 0)
+				appendPQExpBuffer(&tmpbuf, _(", deferrable"));
+
+			if (strcmp(deferred, "t") == 0)
+				appendPQExpBuffer(&tmpbuf, _(", initially deferred"));
+
 			printTableAddFooter(&cont, tmpbuf.data);
 			add_tablespace_footer(&cont, tableinfo.relkind,
 								  tableinfo.tablespace, true);
@@ -1431,6 +1460,26 @@ describeOneTableDetails(const char *schemaname,
 			else
 				appendPQExpBuffer(&buf, "true as indisvalid, ");
 			appendPQExpBuffer(&buf, "pg_catalog.pg_get_indexdef(i.indexrelid, 0, true)");
+			if (pset.sversion >= 80500)
+				appendPQExpBuffer(&buf,
+							  ",\n  (NOT i.indimmediate) AND "
+							  "EXISTS (SELECT 1 FROM pg_catalog.pg_depend d, "
+							  "pg_catalog.pg_constraint con WHERE "
+							  "d.classid = 'pg_catalog.pg_class'::pg_catalog.regclass AND "
+							  "d.objid = i.indexrelid AND "
+							  "d.refclassid = 'pg_catalog.pg_constraint'::pg_catalog.regclass AND "
+							  "d.refobjid = con.oid AND d.deptype = 'i' AND "
+							  "con.condeferrable) AS condeferrable"
+							  ",\n  (NOT i.indimmediate) AND "
+							  "EXISTS (SELECT 1 FROM pg_catalog.pg_depend d, "
+							  "pg_catalog.pg_constraint con WHERE "
+							  "d.classid = 'pg_catalog.pg_class'::pg_catalog.regclass AND "
+							  "d.objid = i.indexrelid AND "
+							  "d.refclassid = 'pg_catalog.pg_constraint'::pg_catalog.regclass AND "
+							  "d.refobjid = con.oid AND d.deptype = 'i' AND "
+							  "con.condeferred) AS condeferred");
+			else
+				appendPQExpBuffer(&buf, ", false AS condeferrable, false AS condeferred");
 			if (pset.sversion >= 80000)
 				appendPQExpBuffer(&buf, ", c2.reltablespace");
 			appendPQExpBuffer(&buf,
@@ -1477,12 +1526,18 @@ describeOneTableDetails(const char *schemaname,
 					if (strcmp(PQgetvalue(result, i, 4), "t") != 0)
 						appendPQExpBuffer(&buf, " INVALID");
 
+					if (strcmp(PQgetvalue(result, i, 6), "t") == 0)
+						appendPQExpBuffer(&buf, " DEFERRABLE");
+
+					if (strcmp(PQgetvalue(result, i, 7), "t") == 0)
+						appendPQExpBuffer(&buf, " INITIALLY DEFERRED");
+
 					printTableAddFooter(&cont, buf.data);
 
 					/* Print tablespace of the index on the same line */
 					if (pset.sversion >= 80000)
 						add_tablespace_footer(&cont, 'i',
-											atooid(PQgetvalue(result, i, 6)),
+											atooid(PQgetvalue(result, i, 8)),
 											  false);
 				}
 			}
@@ -1677,7 +1732,7 @@ describeOneTableDetails(const char *schemaname,
 			PQclear(result);
 		}
 
-		/* print triggers (but ignore foreign-key triggers) */
+		/* print triggers (but ignore RI and unique constraint triggers) */
 		if (tableinfo.hastriggers)
 		{
 			printfPQExpBuffer(&buf,

src/include/access/genam.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.78 2009/06/11 14:49:08 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.79 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,6 +85,34 @@ typedef bool (*IndexBulkDeleteCallback) (ItemPointer itemptr, void *state);
 typedef struct IndexScanDescData *IndexScanDesc;
 typedef struct SysScanDescData *SysScanDesc;
 
+/*
+ * Enumeration specifying the type of uniqueness check to perform in
+ * index_insert().
+ *
+ * UNIQUE_CHECK_YES is the traditional Postgres immediate check, possibly
+ * blocking to see if a conflicting transaction commits.
+ *
+ * For deferrable unique constraints, UNIQUE_CHECK_PARTIAL is specified at
+ * insertion time.  The index AM should test if the tuple is unique, but
+ * should not throw error, block, or prevent the insertion if the tuple
+ * appears not to be unique.  We'll recheck later when it is time for the
+ * constraint to be enforced.  The AM must return true if the tuple is
+ * known unique, false if it is possibly non-unique.  In the "true" case
+ * it is safe to omit the later recheck.
+ *
+ * When it is time to recheck the deferred constraint, a pseudo-insertion
+ * call is made with UNIQUE_CHECK_EXISTING.  The tuple is already in the
+ * index in this case, so it should not be inserted again.  Rather, just
+ * check for conflicting live tuples (possibly blocking).
+ */
+typedef enum IndexUniqueCheck
+{
+	UNIQUE_CHECK_NO,			/* Don't do any uniqueness checking */
+	UNIQUE_CHECK_YES,			/* Enforce uniqueness at insertion time */
+	UNIQUE_CHECK_PARTIAL,		/* Test uniqueness, but no error */
+	UNIQUE_CHECK_EXISTING		/* Check if existing tuple is unique */
+} IndexUniqueCheck;
+
 
 /*
  * generalized index_ interface routines (in indexam.c)
@@ -103,7 +131,7 @@ extern bool index_insert(Relation indexRelation,
 			 Datum *values, bool *isnull,
 			 ItemPointer heap_t_ctid,
 			 Relation heapRelation,
-			 bool check_uniqueness);
+			 IndexUniqueCheck checkUnique);
 
 extern IndexScanDesc index_beginscan(Relation heapRelation,
 				Relation indexRelation,

src/include/access/nbtree.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.124 2009/06/11 14:49:08 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.125 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -517,8 +517,8 @@ extern Datum btoptions(PG_FUNCTION_ARGS);
 /*
  * prototypes for functions in nbtinsert.c
  */
-extern void _bt_doinsert(Relation rel, IndexTuple itup,
+extern bool _bt_doinsert(Relation rel, IndexTuple itup,
-			 bool index_is_unique, Relation heapRel);
+			 IndexUniqueCheck checkUnique, Relation heapRel);
 extern Buffer _bt_getstackbuf(Relation rel, BTStack stack, int access);
 extern void _bt_insert_parent(Relation rel, Buffer buf, Buffer rbuf,
 				  BTStack stack, bool is_root, bool is_only);

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.533 2009/07/28 02:56:30 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.534 2009/07/29 20:56:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200907271
+#define CATALOG_VERSION_NO	200907291
 
 #endif

src/include/catalog/index.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/index.h,v 1.77 2009/01/01 17:23:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/index.h,v 1.78 2009/07/29 20:56:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,6 +39,8 @@ extern Oid index_create(Oid heapRelationId,
 			 Datum reloptions,
 			 bool isprimary,
 			 bool isconstraint,
+			 bool deferrable,
+			 bool initdeferred,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent);

src/include/catalog/pg_attribute.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_attribute.h,v 1.148 2009/06/11 14:49:09 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_attribute.h,v 1.149 2009/07/29 20:56:20 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -469,14 +469,15 @@ DATA(insert ( 1259 tableoid			26 0  4  -7 0 -1 -1 t p i t f f t 0 _null_));
 { 0, {"indnatts"},			21, -1, 2, 3, 0, -1, -1, true, 'p', 's', true, false, false, true, 0, { 0 } }, \
 { 0, {"indisunique"},		16, -1, 1, 4, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
 { 0, {"indisprimary"},		16, -1, 1, 5, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indisclustered"},	16, -1, 1, 6, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indimmediate"},		16, -1, 1, 6, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indisvalid"},		16, -1, 1, 7, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indisclustered"},	16, -1, 1, 7, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indcheckxmin"},		16, -1, 1, 8, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indisvalid"},		16, -1, 1, 8, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indisready"},		16, -1, 1, 9, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indcheckxmin"},		16, -1, 1, 9, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indkey"},			22, -1, -1, 10, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indisready"},		16, -1, 1, 10, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indclass"},			30, -1, -1, 11, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indkey"},			22, -1, -1, 11, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indoption"},			22, -1, -1, 12, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
+{ 0, {"indclass"},			30, -1, -1, 12, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indexprs"},			25, -1, -1, 13, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0, { 0 } }, \
+{ 0, {"indoption"},			22, -1, -1, 13, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0, { 0 } }, \
-{ 0, {"indpred"},			25, -1, -1, 14, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0, { 0 } }
+{ 0, {"indexprs"},			25, -1, -1, 14, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0, { 0 } }, \
+{ 0, {"indpred"},			25, -1, -1, 15, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0, { 0 } }
 
 #endif   /* PG_ATTRIBUTE_H */

src/include/catalog/pg_index.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_index.h,v 1.47 2009/01/01 17:23:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_index.h,v 1.48 2009/07/29 20:56:20 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -35,6 +35,7 @@ CATALOG(pg_index,2610) BKI_WITHOUT_OIDS
 	int2		indnatts;		/* number of columns in index */
 	bool		indisunique;	/* is this a unique index? */
 	bool		indisprimary;	/* is this index for primary key? */
+	bool		indimmediate;	/* is uniqueness enforced immediately? */
 	bool		indisclustered; /* is this the index last clustered by? */
 	bool		indisvalid;		/* is this index valid for use by queries? */
 	bool		indcheckxmin;	/* must we wait for xmin to be old? */
@@ -62,21 +63,22 @@ typedef FormData_pg_index *Form_pg_index;
  *		compiler constants for pg_index
  * ----------------
  */
-#define Natts_pg_index					14
+#define Natts_pg_index					15
 #define Anum_pg_index_indexrelid		1
 #define Anum_pg_index_indrelid			2
 #define Anum_pg_index_indnatts			3
 #define Anum_pg_index_indisunique		4
 #define Anum_pg_index_indisprimary		5
-#define Anum_pg_index_indisclustered	6
+#define Anum_pg_index_indimmediate		6
-#define Anum_pg_index_indisvalid		7
+#define Anum_pg_index_indisclustered	7
-#define Anum_pg_index_indcheckxmin		8
+#define Anum_pg_index_indisvalid		8
-#define Anum_pg_index_indisready		9
+#define Anum_pg_index_indcheckxmin		9
-#define Anum_pg_index_indkey			10
+#define Anum_pg_index_indisready		10
-#define Anum_pg_index_indclass			11
+#define Anum_pg_index_indkey			11
-#define Anum_pg_index_indoption			12
+#define Anum_pg_index_indclass			12
-#define Anum_pg_index_indexprs			13
+#define Anum_pg_index_indoption			13
-#define Anum_pg_index_indpred			14
+#define Anum_pg_index_indexprs			14
+#define Anum_pg_index_indpred			15
 
 /*
  * Index AMs that support ordered scans must support these two indoption

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.546 2009/07/07 18:49:16 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.547 2009/07/29 20:56:20 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -2323,6 +2323,10 @@ DESCR("convert generic options array to name/value table");
 DATA(insert OID = 1619 (  pg_typeof				PGNSP PGUID 12 1 0 0 f f f f f s 1 0 2206 "2276" _null_ _null_ _null_ _null_  pg_typeof _null_ _null_ _null_ ));
 DESCR("returns the type of the argument");
 
+/* Deferrable unique constraint trigger */
+DATA(insert OID = 1250 (  unique_key_recheck	PGNSP PGUID 12 1 0 0 f f f t f v 0 0 2279 "" _null_ _null_ _null_ _null_ unique_key_recheck _null_ _null_ _null_ ));
+DESCR("deferred UNIQUE constraint check");
+
 /* Generic referential integrity constraint triggers */
 DATA(insert OID = 1644 (  RI_FKey_check_ins		PGNSP PGUID 12 1 0 0 f f f t f v 0 0 2279 "" _null_ _null_ _null_ _null_ RI_FKey_check_ins _null_ _null_ _null_ ));
 DESCR("referential integrity FOREIGN KEY ... REFERENCES");

src/include/commands/defrem.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/defrem.h,v 1.95 2009/07/16 06:33:45 petere Exp $
+ * $PostgreSQL: pgsql/src/include/commands/defrem.h,v 1.96 2009/07/29 20:56:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,6 +29,8 @@ extern void DefineIndex(RangeVar *heapRelation,
 			bool unique,
 			bool primary,
 			bool isconstraint,
+			bool deferrable,
+			bool initdeferred,
 			bool is_alter_table,
 			bool check_rights,
 			bool skip_build,

src/include/commands/trigger.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.74 2009/07/28 02:56:31 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.75 2009/07/29 20:56:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -105,7 +105,7 @@ extern PGDLLIMPORT int SessionReplicationRole;
 #define TRIGGER_DISABLED					'D'
 
 extern Oid CreateTrigger(CreateTrigStmt *stmt,
-			  Oid constraintOid, Oid indexOid,
+			  Oid constraintOid, Oid indexOid, const char *prefix,
 			  bool checkPermissions);
 
 extern void DropTrigger(Oid relid, const char *trigname,
@@ -132,7 +132,8 @@ extern HeapTuple ExecBRInsertTriggers(EState *estate,
 					 HeapTuple trigtuple);
 extern void ExecARInsertTriggers(EState *estate,
 					 ResultRelInfo *relinfo,
-					 HeapTuple trigtuple);
+					 HeapTuple trigtuple,
+					 List *recheckIndexes);
 extern void ExecBSDeleteTriggers(EState *estate,
 					 ResultRelInfo *relinfo);
 extern void ExecASDeleteTriggers(EState *estate,
@@ -154,7 +155,8 @@ extern HeapTuple ExecBRUpdateTriggers(EState *estate,
 extern void ExecARUpdateTriggers(EState *estate,
 					 ResultRelInfo *relinfo,
 					 ItemPointer tupleid,
-					 HeapTuple newtuple);
+					 HeapTuple newtuple,
+					 List *recheckIndexes);
 extern void ExecBSTruncateTriggers(EState *estate,
 					   ResultRelInfo *relinfo);
 extern void ExecASTruncateTriggers(EState *estate,

src/include/executor/executor.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.157 2009/07/22 17:00:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.158 2009/07/29 20:56:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -302,8 +302,8 @@ extern void ExecCloseScanRelation(Relation scanrel);
 
 extern void ExecOpenIndices(ResultRelInfo *resultRelInfo);
 extern void ExecCloseIndices(ResultRelInfo *resultRelInfo);
-extern void ExecInsertIndexTuples(TupleTableSlot *slot, ItemPointer tupleid,
+extern List *ExecInsertIndexTuples(TupleTableSlot *slot, ItemPointer tupleid,
-					  EState *estate, bool is_vacuum);
+					  EState *estate, bool is_vacuum_full);
 
 extern void RegisterExprContextCallback(ExprContext *econtext,
 							ExprContextCallbackFunction function,

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.398 2009/07/26 23:34:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.399 2009/07/29 20:56:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1355,7 +1355,7 @@ typedef struct CreateStmt
  * Constraint attributes (DEFERRABLE etc) are initially represented as
  * separate Constraint nodes for simplicity of parsing.  parse_utilcmd.c makes
  * a pass through the constraints list to attach the info to the appropriate
- * FkConstraint node (and, perhaps, someday to other kinds of constraints).
+ * Constraint and FkConstraint nodes.
  * ----------
  */
 
@@ -1385,6 +1385,8 @@ typedef struct Constraint
 	List	   *options;		/* options from WITH clause */
 	char	   *indexspace;		/* index tablespace for PKEY/UNIQUE
 								 * constraints; NULL for default */
+	bool		deferrable;		/* DEFERRABLE */
+	bool		initdeferred;	/* INITIALLY DEFERRED */
 } Constraint;
 
 /* ----------
@@ -1555,12 +1557,11 @@ typedef struct CreateTrigStmt
 	/* events uses the TRIGGER_TYPE bits defined in catalog/pg_trigger.h */
 	int16		events;			/* INSERT/UPDATE/DELETE/TRUNCATE */
 
-	/* The following are used for referential */
+	/* The following are used for constraint triggers (RI and unique checks) */
-	/* integrity constraint triggers */
+	bool		isconstraint;	/* This is a constraint trigger */
-	bool		isconstraint;	/* This is an RI trigger */
 	bool		deferrable;		/* [NOT] DEFERRABLE */
 	bool		initdeferred;	/* INITIALLY {DEFERRED|IMMEDIATE} */
-	RangeVar   *constrrel;		/* opposite relation */
+	RangeVar   *constrrel;		/* opposite relation, if RI trigger */
 } CreateTrigStmt;
 
 /* ----------------------
@@ -1864,6 +1865,8 @@ typedef struct IndexStmt
 	bool		unique;			/* is index unique? */
 	bool		primary;		/* is index on primary key? */
 	bool		isconstraint;	/* is it from a CONSTRAINT clause? */
+	bool		deferrable;		/* is the constraint DEFERRABLE? */
+	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
 } IndexStmt;
 

src/include/utils/builtins.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.334 2009/07/16 06:33:46 petere Exp $
+ * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.335 2009/07/29 20:56:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1029,6 +1029,9 @@ extern Datum window_nth_value(PG_FUNCTION_ARGS);
 /* access/transam/twophase.c */
 extern Datum pg_prepared_xact(PG_FUNCTION_ARGS);
 
+/* commands/constraint.c */
+extern Datum unique_key_recheck(PG_FUNCTION_ARGS);
+
 /* commands/prepare.c */
 extern Datum pg_prepared_statement(PG_FUNCTION_ARGS);
 

src/test/regress/expected/sanity_check.out

@@ -164,7 +164,8 @@ FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = relnamespace
 WHERE relhasoids
     AND ((nspname ~ '^pg_') IS NOT FALSE)
     AND NOT EXISTS (SELECT 1 FROM pg_index i WHERE indrelid = c.oid
-                    AND indkey[0] = -2 AND indnatts = 1 AND indisunique);
+                    AND indkey[0] = -2 AND indnatts = 1
+                    AND indisunique AND indimmediate);
  relname | nspname 
 ---------+---------
 (0 rows)

src/test/regress/input/constraints.source

@@ -259,3 +259,110 @@ SELECT '' AS five, * FROM UNIQUE_TBL;
 
 DROP TABLE UNIQUE_TBL;
 
+--
+-- Deferrable unique constraints
+--
+
+CREATE TABLE unique_tbl (i int UNIQUE DEFERRABLE, t text);
+
+INSERT INTO unique_tbl VALUES (0, 'one');
+INSERT INTO unique_tbl VALUES (1, 'two');
+INSERT INTO unique_tbl VALUES (2, 'tree');
+INSERT INTO unique_tbl VALUES (3, 'four');
+INSERT INTO unique_tbl VALUES (4, 'five');
+
+BEGIN;
+
+-- default is immediate so this should fail right away
+UPDATE unique_tbl SET i = 1 WHERE i = 0;
+
+ROLLBACK;
+
+-- check is done at end of statement, so this should succeed
+UPDATE unique_tbl SET i = i+1;
+
+SELECT * FROM unique_tbl;
+
+-- explicitly defer the constraint
+BEGIN;
+
+SET CONSTRAINTS unique_tbl_i_key DEFERRED;
+
+INSERT INTO unique_tbl VALUES (3, 'three');
+DELETE FROM unique_tbl WHERE t = 'tree'; -- makes constraint valid again
+
+COMMIT; -- should succeed
+
+SELECT * FROM unique_tbl;
+
+-- try adding an initially deferred constraint
+ALTER TABLE unique_tbl DROP CONSTRAINT unique_tbl_i_key;
+ALTER TABLE unique_tbl ADD CONSTRAINT unique_tbl_i_key
+	UNIQUE (i) DEFERRABLE INITIALLY DEFERRED;
+
+BEGIN;
+
+INSERT INTO unique_tbl VALUES (1, 'five');
+INSERT INTO unique_tbl VALUES (5, 'one');
+UPDATE unique_tbl SET i = 4 WHERE i = 2;
+UPDATE unique_tbl SET i = 2 WHERE i = 4 AND t = 'four';
+DELETE FROM unique_tbl WHERE i = 1 AND t = 'one';
+DELETE FROM unique_tbl WHERE i = 5 AND t = 'five';
+
+COMMIT;
+
+SELECT * FROM unique_tbl;
+
+-- should fail at commit-time
+BEGIN;
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+COMMIT; -- should fail
+
+-- make constraint check immediate
+BEGIN;
+
+SET CONSTRAINTS ALL IMMEDIATE;
+
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should fail
+
+COMMIT;
+
+-- forced check when SET CONSTRAINTS is called
+BEGIN;
+
+SET CONSTRAINTS ALL DEFERRED;
+
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+
+SET CONSTRAINTS ALL IMMEDIATE; -- should fail
+
+COMMIT;
+
+-- test a HOT update that invalidates the conflicting tuple.
+-- the trigger should still fire and catch the violation
+
+BEGIN;
+
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+UPDATE unique_tbl SET t = 'THREE' WHERE i = 3 AND t = 'Three';
+
+COMMIT; -- should fail
+
+SELECT * FROM unique_tbl;
+
+-- test a HOT update that modifies the newly inserted tuple,
+-- but should succeed because we then remove the other conflicting tuple.
+
+BEGIN;
+
+INSERT INTO unique_tbl VALUES(3, 'tree'); -- should succeed for now
+UPDATE unique_tbl SET t = 'threex' WHERE t = 'tree';
+DELETE FROM unique_tbl WHERE t = 'three';
+
+SELECT * FROM unique_tbl;
+
+COMMIT;
+
+SELECT * FROM unique_tbl;
+
+DROP TABLE unique_tbl;

src/test/regress/output/constraints.source

@@ -375,3 +375,132 @@ SELECT '' AS five, * FROM UNIQUE_TBL;
 (5 rows)
 
 DROP TABLE UNIQUE_TBL;
+--
+-- Deferrable unique constraints
+--
+CREATE TABLE unique_tbl (i int UNIQUE DEFERRABLE, t text);
+NOTICE:  CREATE TABLE / UNIQUE will create implicit index "unique_tbl_i_key" for table "unique_tbl"
+INSERT INTO unique_tbl VALUES (0, 'one');
+INSERT INTO unique_tbl VALUES (1, 'two');
+INSERT INTO unique_tbl VALUES (2, 'tree');
+INSERT INTO unique_tbl VALUES (3, 'four');
+INSERT INTO unique_tbl VALUES (4, 'five');
+BEGIN;
+-- default is immediate so this should fail right away
+UPDATE unique_tbl SET i = 1 WHERE i = 0;
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+ROLLBACK;
+-- check is done at end of statement, so this should succeed
+UPDATE unique_tbl SET i = i+1;
+SELECT * FROM unique_tbl;
+ i |  t   
+---+------
+ 1 | one
+ 2 | two
+ 3 | tree
+ 4 | four
+ 5 | five
+(5 rows)
+
+-- explicitly defer the constraint
+BEGIN;
+SET CONSTRAINTS unique_tbl_i_key DEFERRED;
+INSERT INTO unique_tbl VALUES (3, 'three');
+DELETE FROM unique_tbl WHERE t = 'tree'; -- makes constraint valid again
+COMMIT; -- should succeed
+SELECT * FROM unique_tbl;
+ i |   t   
+---+-------
+ 1 | one
+ 2 | two
+ 4 | four
+ 5 | five
+ 3 | three
+(5 rows)
+
+-- try adding an initially deferred constraint
+ALTER TABLE unique_tbl DROP CONSTRAINT unique_tbl_i_key;
+ALTER TABLE unique_tbl ADD CONSTRAINT unique_tbl_i_key
+	UNIQUE (i) DEFERRABLE INITIALLY DEFERRED;
+NOTICE:  ALTER TABLE / ADD UNIQUE will create implicit index "unique_tbl_i_key" for table "unique_tbl"
+BEGIN;
+INSERT INTO unique_tbl VALUES (1, 'five');
+INSERT INTO unique_tbl VALUES (5, 'one');
+UPDATE unique_tbl SET i = 4 WHERE i = 2;
+UPDATE unique_tbl SET i = 2 WHERE i = 4 AND t = 'four';
+DELETE FROM unique_tbl WHERE i = 1 AND t = 'one';
+DELETE FROM unique_tbl WHERE i = 5 AND t = 'five';
+COMMIT;
+SELECT * FROM unique_tbl;
+ i |   t   
+---+-------
+ 3 | three
+ 1 | five
+ 5 | one
+ 4 | two
+ 2 | four
+(5 rows)
+
+-- should fail at commit-time
+BEGIN;
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+COMMIT; -- should fail
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+-- make constraint check immediate
+BEGIN;
+SET CONSTRAINTS ALL IMMEDIATE;
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should fail
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+COMMIT;
+-- forced check when SET CONSTRAINTS is called
+BEGIN;
+SET CONSTRAINTS ALL DEFERRED;
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+SET CONSTRAINTS ALL IMMEDIATE; -- should fail
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+COMMIT;
+-- test a HOT update that invalidates the conflicting tuple.
+-- the trigger should still fire and catch the violation
+BEGIN;
+INSERT INTO unique_tbl VALUES (3, 'Three'); -- should succeed for now
+UPDATE unique_tbl SET t = 'THREE' WHERE i = 3 AND t = 'Three';
+COMMIT; -- should fail
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+SELECT * FROM unique_tbl;
+ i |   t   
+---+-------
+ 3 | three
+ 1 | five
+ 5 | one
+ 4 | two
+ 2 | four
+(5 rows)
+
+-- test a HOT update that modifies the newly inserted tuple,
+-- but should succeed because we then remove the other conflicting tuple.
+BEGIN;
+INSERT INTO unique_tbl VALUES(3, 'tree'); -- should succeed for now
+UPDATE unique_tbl SET t = 'threex' WHERE t = 'tree';
+DELETE FROM unique_tbl WHERE t = 'three';
+SELECT * FROM unique_tbl;
+ i |   t    
+---+--------
+ 1 | five
+ 5 | one
+ 4 | two
+ 2 | four
+ 3 | threex
+(5 rows)
+
+COMMIT;
+SELECT * FROM unique_tbl;
+ i |   t    
+---+--------
+ 1 | five
+ 5 | one
+ 4 | two
+ 2 | four
+ 3 | threex
+(5 rows)
+
+DROP TABLE unique_tbl;

src/test/regress/sql/sanity_check.sql

@@ -22,4 +22,5 @@ FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = relnamespace
 WHERE relhasoids
     AND ((nspname ~ '^pg_') IS NOT FALSE)
     AND NOT EXISTS (SELECT 1 FROM pg_index i WHERE indrelid = c.oid
-                    AND indkey[0] = -2 AND indnatts = 1 AND indisunique);
+                    AND indkey[0] = -2 AND indnatts = 1
+                    AND indisunique AND indimmediate);