Revert "Fix parallel-safety check of expressions and predicate for index builds"

This reverts commit eae7be600be7, following a discussion with Tom Lane,
due to concerns that this impacts the decisions made by the planner for
the number of workers spawned based on the inlining and const-folding of
index expressions and predicate for cases that would have worked until
this commit.

Discussion: https://postgr.es/m/162802.1709746091@sss.pgh.pa.us
Backpatch-through: 12

1 files changed, 0 insertions, 68 deletions

diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index b6e9a35d9c5..60978f9415b 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -3505,74 +3505,6 @@ get_index_column_opclass(Oid index_oid, int attno)
 }
 
 /*
- * get_index_expressions
- *
- *		Given the index OID, its a List of its expressions or NIL if none.
- */
-List *
-get_index_expressions(Oid index_oid)
-{
-	List	   *result;
-	HeapTuple	tuple;
-	Datum		exprDatum;
-	bool		isnull;
-	char	   *exprString;
-
-	tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for index %u", index_oid);
-
-	exprDatum = SysCacheGetAttr(INDEXRELID, tuple,
-								Anum_pg_index_indexprs, &isnull);
-	if (isnull)
-	{
-		ReleaseSysCache(tuple);
-		return NIL;
-	}
-
-	exprString = TextDatumGetCString(exprDatum);
-	result = (List *) stringToNode(exprString);
-	pfree(exprString);
-	ReleaseSysCache(tuple);
-
-	return result;
-}
-
-/*
- * get_index_predicate
- *
- *		Given the index OID, return a List of its predicate or NIL if none.
- */
-List *
-get_index_predicate(Oid index_oid)
-{
-	List	   *result;
-	HeapTuple	tuple;
-	Datum		predDatum;
-	bool		isnull;
-	char	   *predString;
-
-	tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
-	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for index %u", index_oid);
-
-	predDatum = SysCacheGetAttr(INDEXRELID, tuple,
-								Anum_pg_index_indpred, &isnull);
-	if (isnull)
-	{
-		ReleaseSysCache(tuple);
-		return NIL;
-	}
-
-	predString = TextDatumGetCString(predDatum);
-	result = (List *) stringToNode(predString);
-	pfree(predString);
-	ReleaseSysCache(tuple);
-
-	return result;
-}
-
-/*
  * get_index_isreplident
  *
  *		Given the index OID, return pg_index.indisreplident.