Fix a couple of problems in pg_get_statisticsextdef

There was a thinko whereby we tested the wrong tuple after fetching it
from cache; avoid that by using generate_relation_name instead, which is
simpler.  Also, the statistics name was not qualified, so add that.  (It
could be argued that qualification should be conditional on the schema
not being on search path.  We can add that later, but at least this form
is correct.)

Author: David Rowley, Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f8RjLeVZJ2+93pdQGuZJeBF-ifsHaFMR-q-6-Z0qxA8cA@mail.gmail.com

1 files changed, 5 insertions, 15 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index d57d5568b28..c2681ced2af 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -1448,11 +1448,10 @@ static char *
 pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 {
 	Form_pg_statistic_ext	statextrec;
-	Form_pg_class			pgclassrec;
 	HeapTuple	statexttup;
-	HeapTuple	pgclasstup;
 	StringInfoData buf;
 	int			colno;
+	char	   *nsp;
 
 	statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
 
@@ -1465,20 +1464,12 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 
 	statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
 
-	pgclasstup = SearchSysCache1(RELOID, ObjectIdGetDatum(statextrec->starelid));
-
-	if (!HeapTupleIsValid(statexttup))
-	{
-		ReleaseSysCache(statexttup);
-		elog(ERROR, "cache lookup failed for relation %u", statextrec->starelid);
-	}
-
-	pgclassrec = (Form_pg_class) GETSTRUCT(pgclasstup);
-
 	initStringInfo(&buf);
 
+	nsp = get_namespace_name(statextrec->stanamespace);
 	appendStringInfo(&buf, "CREATE STATISTICS %s ON (",
-							quote_identifier(NameStr(statextrec->staname)));
+					 quote_qualified_identifier(nsp,
+												NameStr(statextrec->staname)));
 
 	for (colno = 0; colno < statextrec->stakeys.dim1; colno++)
 	{
@@ -1494,10 +1485,9 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 	}
 
 	appendStringInfo(&buf, ") FROM %s",
-							quote_identifier(NameStr(pgclassrec->relname)));
+					 generate_relation_name(statextrec->starelid, NIL));
 
 	ReleaseSysCache(statexttup);
-	ReleaseSysCache(pgclasstup);
 
 	return buf.data;
 }