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.

1 files changed, 47 insertions, 73 deletions

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);
 }