Make stxstattarget nullable

To match attstattarget change (commit 4f622503d6d).  The logic inside
CreateStatistics() is clarified a bit compared to that previous patch,
and so here we also update ATExecSetStatistics() to match.

Reviewed-by: Tomas Vondra <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/[email protected]

1 files changed, 31 insertions, 15 deletions

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index a855f750c75..5f49479832d 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -495,9 +495,9 @@ CreateStatistics(CreateStatsStmt *stmt)
 	values[Anum_pg_statistic_ext_stxrelid - 1] = ObjectIdGetDatum(relid);
 	values[Anum_pg_statistic_ext_stxname - 1] = NameGetDatum(&stxname);
 	values[Anum_pg_statistic_ext_stxnamespace - 1] = ObjectIdGetDatum(namespaceId);
-	values[Anum_pg_statistic_ext_stxstattarget - 1] = Int16GetDatum(-1);
 	values[Anum_pg_statistic_ext_stxowner - 1] = ObjectIdGetDatum(stxowner);
 	values[Anum_pg_statistic_ext_stxkeys - 1] = PointerGetDatum(stxkeys);
+	nulls[Anum_pg_statistic_ext_stxstattarget - 1] = true;
 	values[Anum_pg_statistic_ext_stxkind - 1] = PointerGetDatum(stxkind);
 
 	values[Anum_pg_statistic_ext_stxexprs - 1] = exprsDatum;
@@ -606,23 +606,36 @@ AlterStatistics(AlterStatsStmt *stmt)
 	bool		repl_null[Natts_pg_statistic_ext];
 	bool		repl_repl[Natts_pg_statistic_ext];
 	ObjectAddress address;
-	int			newtarget = stmt->stxstattarget;
+	int			newtarget;
+	bool		newtarget_default;
 
-	/* Limit statistics target to a sane range */
-	if (newtarget < -1)
+	/* -1 was used in previous versions for the default setting */
+	if (stmt->stxstattarget && intVal(stmt->stxstattarget) != -1)
 	{
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("statistics target %d is too low",
-						newtarget)));
+		newtarget = intVal(stmt->stxstattarget);
+		newtarget_default = false;
 	}
-	else if (newtarget > MAX_STATISTICS_TARGET)
+	else
+		newtarget_default = true;
+
+	if (!newtarget_default)
 	{
-		newtarget = MAX_STATISTICS_TARGET;
-		ereport(WARNING,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("lowering statistics target to %d",
-						newtarget)));
+		/* Limit statistics target to a sane range */
+		if (newtarget < 0)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("statistics target %d is too low",
+							newtarget)));
+		}
+		else if (newtarget > MAX_STATISTICS_TARGET)
+		{
+			newtarget = MAX_STATISTICS_TARGET;
+			ereport(WARNING,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("lowering statistics target to %d",
+							newtarget)));
+		}
 	}
 
 	/* lookup OID of the statistics object */
@@ -673,7 +686,10 @@ AlterStatistics(AlterStatsStmt *stmt)
 
 	/* replace the stxstattarget column */
 	repl_repl[Anum_pg_statistic_ext_stxstattarget - 1] = true;
-	repl_val[Anum_pg_statistic_ext_stxstattarget - 1] = Int16GetDatum(newtarget);
+	if (!newtarget_default)
+		repl_val[Anum_pg_statistic_ext_stxstattarget - 1] = Int16GetDatum(newtarget);
+	else
+		repl_null[Anum_pg_statistic_ext_stxstattarget - 1] = true;
 
 	newtup = heap_modify_tuple(oldtup, RelationGetDescr(rel),
 							   repl_val, repl_null, repl_repl);