attoptions-v1.patch

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 24480e3..596591c 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -21,6 +21,7 @@
 #include "access/reloptions.h"
 #include "catalog/pg_type.h"
 #include "commands/defrem.h"
+#include "commands/tablecmds.h"
 #include "commands/tablespace.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.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 b54520f..8acdde8 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -362,7 +362,7 @@ 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)
@@ -479,7 +479,7 @@ 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/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index 7a51b09..35a13e4 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -351,7 +351,8 @@ sub emit_pgattr_row
         attisdropped  => 'f',
         attislocal    => 't',
         attinhcount   => '0',
-        attacl        => '_null_'
+        attacl        => '_null_',
+        attoptions    => '_null_'
     );
     return {%PGATTR_DEFAULTS, %row};
 }
@@ -378,6 +379,7 @@ sub emit_schemapg_row
     $row->{attstorage}  = q|'|  . $row->{attstorage} . q|'|;
     $row->{attalign}    = q|'|  . $row->{attalign}   . q|'|;
     $row->{attacl}      = q|{ 0 }|;
+    $row->{attoptions}  = q|{ 0 }|;
 
     # 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 ce890e1..085d945 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -116,37 +116,37 @@ static List *insert_ordered_unique_oid(List *list, Oid datum);
 static FormData_pg_attribute a1 = {
 	0, {"ctid"}, TIDOID, 0, 0, sizeof(ItemPointerData),
 	SelfItemPointerAttributeNumber, 0, -1, -1,
-	false, 'p', 's', true, false, false, true, 0, {0}
+	false, 'p', 's', true, false, false, true, 0, {0}, {0}
 };
 
 static FormData_pg_attribute a2 = {
 	0, {"oid"}, OIDOID, 0, 0, sizeof(Oid),
 	ObjectIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0, {0}, {0}
 };
 
 static FormData_pg_attribute a3 = {
 	0, {"xmin"}, XIDOID, 0, 0, sizeof(TransactionId),
 	MinTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0, {0}, {0}
 };
 
 static FormData_pg_attribute a4 = {
 	0, {"cmin"}, CIDOID, 0, 0, sizeof(CommandId),
 	MinCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0, {0}, {0}
 };
 
 static FormData_pg_attribute a5 = {
 	0, {"xmax"}, XIDOID, 0, 0, sizeof(TransactionId),
 	MaxTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0, {0}, {0}
 };
 
 static FormData_pg_attribute a6 = {
 	0, {"cmax"}, CIDOID, 0, 0, sizeof(CommandId),
 	MaxCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0, {0}
+	true, 'p', 'i', true, false, false, true, 0, {0}, {0}
 };
 
 /*
@@ -519,8 +519,9 @@ 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);
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 75f65ba..54f321f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -288,6 +288,10 @@ static void ATPrepSetDistinct(Relation rel, const char *colName,
 					Node *newValue);
 static void ATExecSetDistinct(Relation rel, const char *colName,
 				 Node *newValue);
+static void ATPrepSetOptions(Relation rel, const char *colName,
+				 Node *options);
+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,
@@ -2431,6 +2435,13 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			ATPrepSetDistinct(rel, cmd->name, cmd->def);
 			pass = AT_PASS_COL_ATTRS;
 			break;
+		case AT_SetOptions:		/* ALTER COLUMN SET ( options ) */
+		case AT_ResetOptions:	/* ALTER COLUMN RESET ( options ) */
+			ATSimpleRecursion(wqueue, rel, cmd, recurse);
+			/* Performs own permission checks */
+			ATPrepSetOptions(rel, cmd->name, cmd->def);
+			pass = AT_PASS_COL_ATTRS;
+			break;
 		case AT_SetStorage:		/* ALTER COLUMN SET STORAGE */
 			ATSimplePermissions(rel, false);
 			ATSimpleRecursion(wqueue, rel, cmd, recurse);
@@ -2648,6 +2659,12 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_SetDistinct:	/* ALTER COLUMN SET STATISTICS DISTINCT */
 			ATExecSetDistinct(rel, cmd->name, cmd->def);
 			break;
+		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);
 			break;
@@ -4177,6 +4194,31 @@ ATPrepSetDistinct(Relation rel, const char *colName, Node *newValue)
 					   RelationGetRelationName(rel));
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET ( options )
+ * ALTER TABLE ALTER COLUMN RESET ( options )
+ */
+static void
+ATPrepSetOptions(Relation rel, const char *colName, Node *options)
+{
+	/*
+	 * We do our own permission checking because (a) we want to allow options
+	 * to be set on indexes, and (b) we want to allow options to be set 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)
 {
@@ -4240,6 +4282,67 @@ ATExecSetDistinct(Relation rel, const char *colName, Node *newValue)
 	heap_close(attrelation, RowExclusiveLock);
 }
 
+static void
+ATExecSetOptions(Relation rel, const char *colName, Node *options,
+				 bool isReset)
+{
+	Relation	attrelation;
+	HeapTuple	tuple,
+				newtuple;
+	Form_pg_attribute attrtuple;
+	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 = SearchSysCacheAttName(RelationGetRelid(rel), colName);
+
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+	attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+	if (attrtuple->attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"",
+						colName)));
+
+	/* 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);
+	(void) attribute_reloptions(newOptions, true);
+
+	/* 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);
+
+	/* Update system catalog. */
+	simple_heap_update(attrelation, &newtuple->t_self, newtuple);
+	CatalogUpdateIndexes(attrelation, newtuple);
+	heap_freetuple(newtuple);
+
+	heap_close(attrelation, RowExclusiveLock);
+}
+
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  */
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 7aa387e..49fff9f 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -1654,6 +1654,24 @@ alter_table_cmd:
 					n->def = (Node *) $7;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET ( column_parameter = value [, ... ] ) */
+			| ALTER opt_column ColId SET reloptions
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetOptions;
+					n->name = $3;
+					n->def = (Node *) $5;
+					$$ = (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> */
 			| ALTER opt_column ColId SET STORAGE ColId
 				{
diff --git a/src/include/access/reloptions.h b/src/include/access/reloptions.h
index a0087bc..db21390 100644
--- a/src/include/access/reloptions.h
+++ b/src/include/access/reloptions.h
@@ -40,7 +40,8 @@ typedef enum relopt_kind
 	RELOPT_KIND_HASH = (1 << 3),
 	RELOPT_KIND_GIN = (1 << 4),
 	RELOPT_KIND_GIST = (1 << 5),
-	RELOPT_KIND_TABLESPACE = (1 << 6),
+	RELOPT_KIND_ATTRIBUTE = (1 << 6),
+	RELOPT_KIND_TABLESPACE = (1 << 7),
 	/* if you add a new kind, make sure you update "last_default" too */
 	RELOPT_KIND_LAST_DEFAULT = RELOPT_KIND_TABLESPACE,
 	/* some compilers treat enums as signed ints, so we can't use 1 << 31 */
@@ -266,6 +267,7 @@ extern bytea *default_reloptions(Datum reloptions, bool validate,
 extern bytea *heap_reloptions(char relkind, Datum reloptions, bool validate);
 extern bytea *index_reloptions(RegProcedure amoptions, Datum reloptions,
 				 bool validate);
+extern bytea *attribute_reloptions(Datum reloptions, bool validate);
 extern bytea *tablespace_reloptions(Datum reloptions, bool validate);
 
 #endif   /* RELOPTIONS_H */
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 6fdc6b8..998418b 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -157,6 +157,9 @@ CATALOG(pg_attribute,1249) BKI_BOOTSTRAP BKI_WITHOUT_OIDS BKI_ROWTYPE_OID(75) BK
 
 	/* Column-level access permissions */
 	aclitem		attacl[1];
+
+	/* Column-level options */
+	aclitem		attoptions[1];
 } FormData_pg_attribute;
 
 /*
@@ -180,7 +183,7 @@ typedef FormData_pg_attribute *Form_pg_attribute;
  * ----------------
  */
 
-#define Natts_pg_attribute				19
+#define Natts_pg_attribute				20
 #define Anum_pg_attribute_attrelid		1
 #define Anum_pg_attribute_attname		2
 #define Anum_pg_attribute_atttypid		3
@@ -200,6 +203,7 @@ typedef FormData_pg_attribute *Form_pg_attribute;
 #define Anum_pg_attribute_attislocal	17
 #define Anum_pg_attribute_attinhcount	18
 #define Anum_pg_attribute_attacl		19
+#define Anum_pg_attribute_attoptions	20
 
 
 /* ----------------
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index c5b15f5..2f40198 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -128,7 +128,7 @@ typedef FormData_pg_class *Form_pg_class;
 /* Note: "3" in the relfrozenxid column stands for FirstNormalTransactionId */
 DATA(insert OID = 1247 (  pg_type		PGNSP 71 PGUID 0 1247 0 0 0 0 0 f f f r 28 0 t f f f f f 3 _null_ _null_ ));
 DESCR("");
-DATA(insert OID = 1249 (  pg_attribute	PGNSP 75 PGUID 0 1249 0 0 0 0 0 f f f r 19 0 f f f f f f 3 _null_ _null_ ));
+DATA(insert OID = 1249 (  pg_attribute	PGNSP 75 PGUID 0 1249 0 0 0 0 0 f f f r 20 0 f f f f f f 3 _null_ _null_ ));
 DESCR("");
 DATA(insert OID = 1255 (  pg_proc		PGNSP 81 PGUID 0 1255 0 0 0 0 0 f f f r 25 0 t f f f f f 3 _null_ _null_ ));
 DESCR("");
diff --git a/src/include/commands/tablecmds.h b/src/include/commands/tablecmds.h
index 8bc716a..276d1eb 100644
--- a/src/include/commands/tablecmds.h
+++ b/src/include/commands/tablecmds.h
@@ -17,6 +17,11 @@
 #include "nodes/parsenodes.h"
 #include "utils/relcache.h"
 
+typedef struct AttributeOpts
+{
+	float8		n_distinct;
+	float8		n_distinct_inherited;
+} AttributeOpts;
 
 extern Oid	DefineRelation(CreateStmt *stmt, char relkind);
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index e05f93b..32ba917 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1102,6 +1102,8 @@ typedef enum AlterTableType
 	AT_SetNotNull,				/* alter column set not null */
 	AT_SetStatistics,			/* alter column set statistics */
 	AT_SetDistinct,				/* alter column set statistics distinct */
+	AT_SetOptions,				/* alter column set ( options ) */
+	AT_ResetOptions,			/* alter column reset ( options ) */
 	AT_SetStorage,				/* alter column set storage */
 	AT_DropColumn,				/* drop column */
 	AT_DropColumnRecurse,		/* internal to commands/tablecmds.c */