diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index c1d1505..c4d6b9b 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -761,7 +761,9 @@ fmgr_internal_validator(PG_FUNCTION_ARGS)
 
 	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for function %u", funcoid);
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function with OID %u does not exist", funcoid)));
 
 	tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 	if (isnull)
@@ -810,7 +812,9 @@ fmgr_c_validator(PG_FUNCTION_ARGS)
 
 	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for function %u", funcoid);
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function with OID %u does not exist", funcoid)));
 
 	tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 	if (isnull)
@@ -858,7 +862,9 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
 
 	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for function %u", funcoid);
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function with OID %u does not exist", funcoid)));
 	proc = (Form_pg_proc) GETSTRUCT(tuple);
 
 	/* Disallow pseudotype result */
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 13ae6ad..37bfd6a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -2265,7 +2265,10 @@ getBaseTypeAndTypmod(Oid typid, int32 *typmod)
 
 		tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
 		if (!HeapTupleIsValid(tup))
-			elog(ERROR, "cache lookup failed for type %u", typid);
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_OBJECT),
+					 errmsg("type with OID %u does not exist",
+							typid)));
 		typTup = (Form_pg_type) GETSTRUCT(tup);
 		if (typTup->typtype != TYPTYPE_DOMAIN)
 		{
diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c
index ea6f787..98db0db 100644
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -231,7 +231,10 @@ lookup_type_cache(Oid type_id, int flags)
 
 		tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type_id));
 		if (!HeapTupleIsValid(tp))
-			elog(ERROR, "cache lookup failed for type %u", type_id);
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_OBJECT),
+					 errmsg("type with OID %u does not exist",
+							type_id)));
 		typtup = (Form_pg_type) GETSTRUCT(tp);
 		if (!typtup->typisdefined)
 			ereport(ERROR,
diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c
index 7e6a60d..231425b 100644
--- a/src/backend/utils/fmgr/fmgr.c
+++ b/src/backend/utils/fmgr/fmgr.c
@@ -2509,7 +2509,9 @@ CheckFunctionValidatorAccess(Oid validatorOid, Oid functionOid)
 	/* Get the function's pg_proc entry */
 	procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionOid));
 	if (!HeapTupleIsValid(procTup))
-		elog(ERROR, "cache lookup failed for function %u", functionOid);
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function with OID %u does not exist", functionOid)));
 	procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 
 	/*
diff --git a/src/pl/plpgsql/src/pl_handler.c b/src/pl/plpgsql/src/pl_handler.c
index 36868fb..1dd6eda 100644
--- a/src/pl/plpgsql/src/pl_handler.c
+++ b/src/pl/plpgsql/src/pl_handler.c
@@ -412,7 +412,9 @@ plpgsql_validator(PG_FUNCTION_ARGS)
 	/* Get the new function's pg_proc entry */
 	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for function %u", funcoid);
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function with OID %u does not exist", funcoid)));
 	proc = (Form_pg_proc) GETSTRUCT(tuple);
 
 	functyptype = get_typtype(proc->prorettype);