Replace ALTER TABLE ... SET STATISTICS DISTINCT with a more general mechanism.

Attributes can now have options, just as relations and tablespaces do, and
the reloptions code is used to parse, validate, and store them.  For
simplicity and because these options are not performance critical, we store
them in a separate cache rather than the main relcache.

Thanks to Alex Hunsaker for the review.

10 files changed, 179 insertions, 124 deletions

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 28eacb4e478..65328a9f288 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/reloptions.c,v 1.31 2010/01/05 21:53:58 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/reloptions.c,v 1.32 2010/01/22 16:40:18 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,6 +24,7 @@
 #include "commands/tablespace.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
+#include "utils/attoptcache.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/memutils.h"
@@ -196,6 +197,22 @@ static relopt_real realRelOpts[] =
 		},
 		-1, 0.0, DBL_MAX
 	},
+	{
+		{
+			"n_distinct",
+			"Sets the planner's estimate of the number of distinct values appearing in a column (excluding child relations).",
+			RELOPT_KIND_ATTRIBUTE
+		},
+		0, -1.0, DBL_MAX
+	},
+	{
+		{
+			"n_distinct_inherited",
+			"Sets the planner's estimate of the number of distinct values appearing in a column (including child relations).",
+			RELOPT_KIND_ATTRIBUTE
+		},
+		0, -1.0, DBL_MAX
+	},
 	/* list terminator */
 	{{NULL}}
 };
@@ -1187,6 +1204,37 @@ index_reloptions(RegProcedure amoptions, Datum reloptions, bool validate)
 }
 
 /*
+ * Option parser for attribute reloptions
+ */
+bytea *
+attribute_reloptions(Datum reloptions, bool validate)
+{
+	relopt_value *options;
+	AttributeOpts  *aopts;
+	int			numoptions;
+	static const relopt_parse_elt tab[] = {
+		{"n_distinct", RELOPT_TYPE_REAL, offsetof(AttributeOpts, n_distinct)},
+		{"n_distinct_inherited", RELOPT_TYPE_REAL, offsetof(AttributeOpts, n_distinct_inherited)}
+	};
+
+	options = parseRelOptions(reloptions, validate, RELOPT_KIND_ATTRIBUTE,
+							  &numoptions);
+
+	/* if none set, we're done */
+	if (numoptions == 0)
+		return NULL;
+
+	aopts = allocateReloptStruct(sizeof(AttributeOpts), options, numoptions);
+
+	fillRelOptions((void *) aopts, sizeof(AttributeOpts), options, numoptions,
+				   validate, tab, lengthof(tab));
+
+	pfree(options);
+
+	return (bytea *) aopts;
+}
+
+/*
  * Option parser for tablespace reloptions
  */
 bytea *
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index a39b4922d87..9edecda2d88 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.131 2010/01/02 16:57:33 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.132 2010/01/22 16:40:18 rhaas Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -338,8 +338,6 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attstattarget != attr2->attstattarget)
 			return false;
-		if (attr1->attdistinct != attr2->attdistinct)
-			return false;
 		if (attr1->attlen != attr2->attlen)
 			return false;
 		if (attr1->attndims != attr2->attndims)
@@ -362,7 +360,7 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attinhcount != attr2->attinhcount)
 			return false;
-		/* attacl is ignored, since it's not even present... */
+		/* attacl and attoptions are not even present... */
 	}
 
 	if (tupdesc1->constr != NULL)
@@ -467,7 +465,6 @@ TupleDescInitEntry(TupleDesc desc,
 		MemSet(NameStr(att->attname), 0, NAMEDATALEN);
 
 	att->attstattarget = -1;
-	att->attdistinct = 0;
 	att->attcacheoff = -1;
 	att->atttypmod = typmod;
 
@@ -479,7 +476,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attisdropped = false;
 	att->attislocal = true;
 	att->attinhcount = 0;
-	/* attacl is not set because it's not present in tupledescs */
+	/* attacl and attoptions are not present in tupledescs */
 
 	tuple = SearchSysCache(TYPEOID,
 						   ObjectIdGetDatum(oidtypeid),
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 39658966085..14e4b839e44 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.257 2010/01/20 09:16:23 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.258 2010/01/22 16:40:18 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -737,7 +737,6 @@ DefineAttr(char *name, char *type, int attnum)
 	}
 
 	attrtypes[attnum]->attstattarget = -1;
-	attrtypes[attnum]->attdistinct = 0;
 	attrtypes[attnum]->attcacheoff = -1;
 	attrtypes[attnum]->atttypmod = -1;
 	attrtypes[attnum]->attislocal = true;
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index 573f4c80a13..008ae46465e 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -10,7 +10,7 @@
 # Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
 # Portions Copyright (c) 1994, Regents of the University of California
 #
-# $PostgreSQL: pgsql/src/backend/catalog/genbki.pl,v 1.6 2010/01/06 22:02:45 tgl Exp $
+# $PostgreSQL: pgsql/src/backend/catalog/genbki.pl,v 1.7 2010/01/22 16:40:18 rhaas Exp $
 #
 #----------------------------------------------------------------------
 
@@ -200,7 +200,8 @@ foreach my $catname ( @{ $catalogs->{names} } )
                 # Store schemapg entries for later.
                 $row = emit_schemapg_row($row, grep { $bki_attr{$_} eq 'bool' } @attnames);
                 push @{ $schemapg_entries{$table_name} },
-                  '{ ' . join(', ', map $row->{$_}, @attnames) . ' }';
+					'{ ' . join(', ', grep { defined $_ }
+					map $row->{$_}, @attnames) . ' }';
             }
 
             # Generate entries for system attributes.
@@ -351,14 +352,14 @@ sub emit_pgattr_row
 
     # Add in default values for pg_attribute
     my %PGATTR_DEFAULTS = (
-        attdistinct   => '0',
         attcacheoff   => '-1',
         atttypmod     => '-1',
         atthasdef     => 'f',
         attisdropped  => 'f',
         attislocal    => 't',
         attinhcount   => '0',
-        attacl        => '_null_'
+        attacl        => '_null_',
+        attoptions    => '_null_'
     );
     return {%PGATTR_DEFAULTS, %row};
 }
@@ -384,7 +385,11 @@ sub emit_schemapg_row
     $row->{attname}     = q|{"| . $row->{attname}    . q|"}|;
     $row->{attstorage}  = q|'|  . $row->{attstorage} . q|'|;
     $row->{attalign}    = q|'|  . $row->{attalign}   . q|'|;
-    $row->{attacl}      = q|{ 0 }|;
+
+    # We don't emit initializers for the variable length fields at all.
+    # Only the fixed-size portions of the descriptors are ever used.
+    delete $row->{attacl};
+    delete $row->{attoptions};
 
     # Expand booleans from 'f'/'t' to 'false'/'true'.
     # Some values might be other macros (eg FLOAT4PASSBYVAL), don't change.
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 6f0894b2143..920e00f1012 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.366 2010/01/06 05:18:18 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.367 2010/01/22 16:40:18 rhaas Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -116,40 +116,46 @@ Oid binary_upgrade_next_toast_relfilenode = InvalidOid;
  *		Disadvantage:  special cases will be all over the place.
  */
 
+/*
+ * The initializers below do not include the attoptions or attacl fields,
+ * but that's OK - we're never going to reference anything beyond the
+ * fixed-size portion of the structure anyway.
+ */
+
 static FormData_pg_attribute a1 = {
-	0, {"ctid"}, TIDOID, 0, 0, sizeof(ItemPointerData),
+	0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
 	SelfItemPointerAttributeNumber, 0, -1, -1,
-	false, 'p', 's', true, false, false, true, 0, {0}
+	false, 'p', 's', true, false, false, true, 0
 };
 
 static FormData_pg_attribute a2 = {
-	0, {"oid"}, OIDOID, 0, 0, sizeof(Oid),
+	0, {"oid"}, OIDOID, 0, sizeof(Oid),
 	ObjectIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 static FormData_pg_attribute a3 = {
-	0, {"xmin"}, XIDOID, 0, 0, sizeof(TransactionId),
+	0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
 	MinTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 static FormData_pg_attribute a4 = {
-	0, {"cmin"}, CIDOID, 0, 0, sizeof(CommandId),
+	0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
 	MinCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 static FormData_pg_attribute a5 = {
-	0, {"xmax"}, XIDOID, 0, 0, sizeof(TransactionId),
+	0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
 	MaxTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 static FormData_pg_attribute a6 = {
-	0, {"cmax"}, CIDOID, 0, 0, sizeof(CommandId),
+	0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
 	MaxCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 /*
@@ -159,9 +165,9 @@ static FormData_pg_attribute a6 = {
  * used in SQL.
  */
 static FormData_pg_attribute a7 = {
-	0, {"tableoid"}, OIDOID, 0, 0, sizeof(Oid),
+	0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
 	TableOidAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0
 };
 
 static const Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7};
@@ -482,13 +488,12 @@ CheckAttributeType(const char *attname, Oid atttypid)
  *		Construct and insert a new tuple in pg_attribute.
  *
  * Caller has already opened and locked pg_attribute.  new_attribute is the
- * attribute to insert (but we ignore its attacl, if indeed it has one).
+ * attribute to insert (but we ignore attacl and attoptions, which are always
+ * initialized to NULL).
  *
  * indstate is the index state for CatalogIndexInsert.	It can be passed as
  * NULL, in which case we'll fetch the necessary info.  (Don't do this when
  * inserting multiple attributes, because it's a tad more expensive.)
- *
- * We always initialize attacl to NULL (i.e., default permissions).
  */
 void
 InsertPgAttributeTuple(Relation pg_attribute_rel,
@@ -507,7 +512,6 @@ InsertPgAttributeTuple(Relation pg_attribute_rel,
 	values[Anum_pg_attribute_attname - 1] = NameGetDatum(&new_attribute->attname);
 	values[Anum_pg_attribute_atttypid - 1] = ObjectIdGetDatum(new_attribute->atttypid);
 	values[Anum_pg_attribute_attstattarget - 1] = Int32GetDatum(new_attribute->attstattarget);
-	values[Anum_pg_attribute_attdistinct - 1] = Float4GetDatum(new_attribute->attdistinct);
 	values[Anum_pg_attribute_attlen - 1] = Int16GetDatum(new_attribute->attlen);
 	values[Anum_pg_attribute_attnum - 1] = Int16GetDatum(new_attribute->attnum);
 	values[Anum_pg_attribute_attndims - 1] = Int32GetDatum(new_attribute->attndims);
@@ -522,8 +526,9 @@ InsertPgAttributeTuple(Relation pg_attribute_rel,
 	values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(new_attribute->attislocal);
 	values[Anum_pg_attribute_attinhcount - 1] = Int32GetDatum(new_attribute->attinhcount);
 
-	/* start out with empty permissions */
+	/* start out with empty permissions and empty options */
 	nulls[Anum_pg_attribute_attacl - 1] = true;
+	nulls[Anum_pg_attribute_attoptions - 1] = true;
 
 	tup = heap_form_tuple(RelationGetDescr(pg_attribute_rel), values, nulls);
 
@@ -578,7 +583,6 @@ AddNewAttributeTuples(Oid new_rel_oid,
 		attr->attrelid = new_rel_oid;
 		/* Make sure these are OK, too */
 		attr->attstattarget = -1;
-		attr->attdistinct = 0;
 		attr->attcacheoff = -1;
 
 		InsertPgAttributeTuple(rel, attr, indstate);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index b84c586a99a..ed70f973296 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.330 2010/01/17 22:56:21 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.331 2010/01/22 16:40:18 rhaas Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -203,7 +203,6 @@ ConstructTupleDescriptor(Relation heapRelation,
 			to->attnum = i + 1;
 
 			to->attstattarget = -1;
-			to->attdistinct = 0;
 			to->attcacheoff = -1;
 			to->attnotnull = false;
 			to->atthasdef = false;
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 7d4087c915b..f27a6dad2e6 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.147 2010/01/02 16:57:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.148 2010/01/22 16:40:18 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,6 +39,7 @@
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "utils/acl.h"
+#include "utils/attoptcache.h"
 #include "utils/datum.h"
 #include "utils/guc.h"
 #include "utils/lsyscache.h"
@@ -493,6 +494,8 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
 		for (i = 0; i < attr_cnt; i++)
 		{
 			VacAttrStats *stats = vacattrstats[i];
+			AttributeOpts *aopt =
+				get_attribute_options(onerel->rd_id, stats->attr->attnum);
 
 			stats->rows = rows;
 			stats->tupDesc = onerel->rd_att;
@@ -501,9 +504,17 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
 									 numrows,
 									 totalrows);
 
-			/* If attdistinct is set, override with that value */
-			if (stats->attr->attdistinct != 0)
-				stats->stadistinct = stats->attr->attdistinct;
+			/*
+			 * If the appropriate flavor of the n_distinct option is
+			 * specified, override with the corresponding value.
+			 */
+			if (aopt != NULL)
+			{
+				float8	n_distinct =
+					inh ? aopt->n_distinct_inherited : aopt->n_distinct;
+				if (n_distinct != 0.0)
+					stats->stadistinct = n_distinct;
+			}
 
 			MemoryContextResetAndDeleteChildren(col_context);
 		}
@@ -751,6 +762,9 @@ compute_index_stats(Relation onerel, double totalrows,
 			for (i = 0; i < attr_cnt; i++)
 			{
 				VacAttrStats *stats = thisdata->vacattrstats[i];
+				AttributeOpts *aopt =
+					get_attribute_options(stats->attr->attrelid,
+						stats->attr->attnum);
 
 				stats->exprvals = exprvals + i;
 				stats->exprnulls = exprnulls + i;
@@ -759,9 +773,15 @@ compute_index_stats(Relation onerel, double totalrows,
 										 ind_fetch_func,
 										 numindexrows,
 										 totalindexrows);
-				/* If attdistinct is set, override with that value */
-				if (stats->attr->attdistinct != 0)
-					stats->stadistinct = stats->attr->attdistinct;
+
+				/*
+				 * If the n_distinct option is specified, it overrides the
+				 * above computation.  For indices, we always use just
+				 * n_distinct, not n_distinct_inherited.
+				 */
+				if (aopt != NULL && aopt->n_distinct != 0.0)
+					stats->stadistinct = aopt->n_distinct;
+
 				MemoryContextResetAndDeleteChildren(col_context);
 			}
 		}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0c5ccdcb45e..e1b45325836 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.317 2010/01/20 19:43:40 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.318 2010/01/22 16:40:18 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -284,10 +284,8 @@ static void ATPrepSetStatistics(Relation rel, const char *colName,
 					Node *newValue);
 static void ATExecSetStatistics(Relation rel, const char *colName,
 					Node *newValue);
-static void ATPrepSetDistinct(Relation rel, const char *colName,
-					Node *newValue);
-static void ATExecSetDistinct(Relation rel, const char *colName,
-				 Node *newValue);
+static void ATExecSetOptions(Relation rel, const char *colName,
+				 Node *options, bool isReset);
 static void ATExecSetStorage(Relation rel, const char *colName,
 				 Node *newValue);
 static void ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
@@ -2425,10 +2423,10 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			ATPrepSetStatistics(rel, cmd->name, cmd->def);
 			pass = AT_PASS_COL_ATTRS;
 			break;
-		case AT_SetDistinct:	/* ALTER COLUMN SET STATISTICS DISTINCT */
-			ATSimpleRecursion(wqueue, rel, cmd, recurse);
-			/* Performs own permission checks */
-			ATPrepSetDistinct(rel, cmd->name, cmd->def);
+		case AT_SetOptions:		/* ALTER COLUMN SET ( options ) */
+		case AT_ResetOptions:	/* ALTER COLUMN RESET ( options ) */
+			ATSimplePermissionsRelationOrIndex(rel);
+			/* This command never recurses */
 			pass = AT_PASS_COL_ATTRS;
 			break;
 		case AT_SetStorage:		/* ALTER COLUMN SET STORAGE */
@@ -2644,8 +2642,11 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_SetStatistics:	/* ALTER COLUMN SET STATISTICS */
 			ATExecSetStatistics(rel, cmd->name, cmd->def);
 			break;
-		case AT_SetDistinct:	/* ALTER COLUMN SET STATISTICS DISTINCT */
-			ATExecSetDistinct(rel, cmd->name, cmd->def);
+		case AT_SetOptions:		/* ALTER COLUMN SET ( options ) */
+			ATExecSetOptions(rel, cmd->name, cmd->def, false);
+			break;
+		case AT_ResetOptions:	/* ALTER COLUMN RESET ( options ) */
+			ATExecSetOptions(rel, cmd->name, cmd->def, true);
 			break;
 		case AT_SetStorage:		/* ALTER COLUMN SET STORAGE */
 			ATExecSetStorage(rel, cmd->name, cmd->def);
@@ -3682,7 +3683,6 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 	namestrcpy(&(attribute.attname), colDef->colname);
 	attribute.atttypid = typeOid;
 	attribute.attstattarget = (newattnum > 0) ? -1 : 0;
-	attribute.attdistinct = 0;
 	attribute.attlen = tform->typlen;
 	attribute.attcacheoff = -1;
 	attribute.atttypmod = typmod;
@@ -4151,68 +4151,24 @@ ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
 	heap_close(attrelation, RowExclusiveLock);
 }
 
-/*
- * ALTER TABLE ALTER COLUMN SET STATISTICS DISTINCT
- */
-static void
-ATPrepSetDistinct(Relation rel, const char *colName, Node *newValue)
-{
-	/*
-	 * We do our own permission checking because (a) we want to allow SET
-	 * DISTINCT on indexes (for expressional index columns), and (b) we want
-	 * to allow SET DISTINCT on system catalogs without requiring
-	 * allowSystemTableMods to be turned on.
-	 */
-	if (rel->rd_rel->relkind != RELKIND_RELATION &&
-		rel->rd_rel->relkind != RELKIND_INDEX)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table or index",
-						RelationGetRelationName(rel))));
-
-	/* Permissions checks */
-	if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
-					   RelationGetRelationName(rel));
-}
-
 static void
-ATExecSetDistinct(Relation rel, const char *colName, Node *newValue)
+ATExecSetOptions(Relation rel, const char *colName, Node *options,
+				 bool isReset)
 {
-	float4		newdistinct;
 	Relation	attrelation;
-	HeapTuple	tuple;
+	HeapTuple	tuple,
+				newtuple;
 	Form_pg_attribute attrtuple;
-
-	switch (nodeTag(newValue))
-	{
-		case T_Integer:
-			newdistinct = intVal(newValue);
-			break;
-		case T_Float:
-			newdistinct = floatVal(newValue);
-			break;
-		default:
-			elog(ERROR, "unrecognized node type: %d",
-				 (int) nodeTag(newValue));
-			newdistinct = 0;	/* keep compiler quiet */
-			break;
-	}
-
-	/*
-	 * Limit ndistinct to sane values
-	 */
-	if (newdistinct < -1.0)
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("number of distinct values %g is too low",
-						newdistinct)));
-	}
+	Datum		datum,
+				newOptions;
+	bool		isnull;
+	Datum		repl_val[Natts_pg_attribute];
+	bool		repl_null[Natts_pg_attribute];
+	bool		repl_repl[Natts_pg_attribute];
 
 	attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
 
-	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
 
 	if (!HeapTupleIsValid(tuple))
 		ereport(ERROR,
@@ -4227,14 +4183,32 @@ ATExecSetDistinct(Relation rel, const char *colName, Node *newValue)
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	attrtuple->attdistinct = newdistinct;
-
-	simple_heap_update(attrelation, &tuple->t_self, tuple);
+	/* Generate new proposed attoptions (text array) */
+	Assert(IsA(options, List));
+	datum = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attoptions,
+		&isnull);
+	newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
+									 (List *) options, NULL, NULL, false,
+									 isReset);
+	/* Validate new options */
+	(void) attribute_reloptions(newOptions, true);
 
-	/* keep system catalog indexes current */
-	CatalogUpdateIndexes(attrelation, tuple);
+	/* Build new tuple. */
+	memset(repl_null, false, sizeof(repl_null));
+	memset(repl_repl, false, sizeof(repl_repl));
+	if (newOptions != (Datum) 0)
+		repl_val[Anum_pg_attribute_attoptions - 1] = newOptions;
+	else
+		repl_null[Anum_pg_attribute_attoptions - 1] = true;
+	repl_repl[Anum_pg_attribute_attoptions - 1] = true;
+	newtuple = heap_modify_tuple(tuple, RelationGetDescr(attrelation),
+								 repl_val, repl_null, repl_repl);
+	ReleaseSysCache(tuple);
 
-	heap_freetuple(tuple);
+	/* Update system catalog. */
+	simple_heap_update(attrelation, &newtuple->t_self, newtuple);
+	CatalogUpdateIndexes(attrelation, newtuple);
+	heap_freetuple(newtuple);
 
 	heap_close(attrelation, RowExclusiveLock);
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index af26d808633..c81e8a38ec9 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.703 2010/01/06 05:31:13 itagaki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.704 2010/01/22 16:40:18 rhaas Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -1645,13 +1645,22 @@ alter_table_cmd:
 					n->def = (Node *) makeInteger($6);
 					$$ = (Node *)n;
 				}
-			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET STATISTICS DISTINCT <NumericOnly> */
-			| ALTER opt_column ColId SET STATISTICS DISTINCT NumericOnly
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET ( column_parameter = value [, ... ] ) */
+			| ALTER opt_column ColId SET reloptions
 				{
 					AlterTableCmd *n = makeNode(AlterTableCmd);
-					n->subtype = AT_SetDistinct;
+					n->subtype = AT_SetOptions;
 					n->name = $3;
-					n->def = (Node *) $7;
+					n->def = (Node *) $5;
+					$$ = (Node *)n;
+				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET ( column_parameter = value [, ... ] ) */
+			| ALTER opt_column ColId RESET reloptions
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_ResetOptions;
+					n->name = $3;
+					n->def = (Node *) $5;
 					$$ = (Node *)n;
 				}
 			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET STORAGE <storagemode> */
diff --git a/src/backend/utils/cache/Makefile b/src/backend/utils/cache/Makefile
index 1a3d2cc482e..617cb677f7a 100644
--- a/src/backend/utils/cache/Makefile
+++ b/src/backend/utils/cache/Makefile
@@ -4,7 +4,7 @@
 #    Makefile for utils/cache
 #
 # IDENTIFICATION
-#    $PostgreSQL: pgsql/src/backend/utils/cache/Makefile,v 1.24 2010/01/05 21:53:59 rhaas Exp $
+#    $PostgreSQL: pgsql/src/backend/utils/cache/Makefile,v 1.25 2010/01/22 16:40:19 rhaas Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -12,7 +12,7 @@ subdir = src/backend/utils/cache
 top_builddir = ../../../..
 include $(top_builddir)/src/Makefile.global
 
-OBJS = catcache.o inval.o plancache.o relcache.o \
+OBJS = attoptcache.o catcache.o inval.o plancache.o relcache.o \
 	spccache.o syscache.o lsyscache.o typcache.o ts_cache.o
 
 include $(top_srcdir)/src/backend/common.mk