Pass collations to functions in FunctionCallInfoData, not FmgrInfo.

Since collation is effectively an argument, not a property of the function,
FmgrInfo is really the wrong place for it; and this becomes critical in
cases where a cached FmgrInfo is used for varying purposes that might need
different collation settings.  Fix by passing it in FunctionCallInfoData
instead.  In particular this allows a clean fix for bug #5970 (record_cmp
not working).  This requires touching a bit more code than the original
method, but nobody ever thought that collations would not be an invasive
patch...

2 files changed, 15 insertions, 19 deletions

diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index e4488a925de..4eb31318ffd 100644
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -137,12 +137,13 @@ gistindex_keytest(IndexScanDesc scan,
 			 */
 			recheck = true;
 
-			test = FunctionCall5(&key->sk_func,
-								 PointerGetDatum(&de),
-								 key->sk_argument,
-								 Int32GetDatum(key->sk_strategy),
-								 ObjectIdGetDatum(key->sk_subtype),
-								 PointerGetDatum(&recheck));
+			test = FunctionCall5Coll(&key->sk_func,
+									 key->sk_collation,
+									 PointerGetDatum(&de),
+									 key->sk_argument,
+									 Int32GetDatum(key->sk_strategy),
+									 ObjectIdGetDatum(key->sk_subtype),
+									 PointerGetDatum(&recheck));
 
 			if (!DatumGetBool(test))
 				return false;
@@ -195,11 +196,12 @@ gistindex_keytest(IndexScanDesc scan,
 			 * can't tolerate lossy distance calculations on leaf tuples;
 			 * there is no opportunity to re-sort the tuples afterwards.
 			 */
-			dist = FunctionCall4(&key->sk_func,
-								 PointerGetDatum(&de),
-								 key->sk_argument,
-								 Int32GetDatum(key->sk_strategy),
-								 ObjectIdGetDatum(key->sk_subtype));
+			dist = FunctionCall4Coll(&key->sk_func,
+									 key->sk_collation,
+									 PointerGetDatum(&de),
+									 key->sk_argument,
+									 Int32GetDatum(key->sk_strategy),
+									 ObjectIdGetDatum(key->sk_subtype));
 
 			*distance_p = DatumGetFloat8(dist);
 		}
diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c
index 67308ed37e5..5662a3a4aab 100644
--- a/src/backend/access/gist/gistscan.c
+++ b/src/backend/access/gist/gistscan.c
@@ -169,8 +169,7 @@ gistrescan(PG_FUNCTION_ARGS)
 		 * comparisons. The original operator is passed to the Consistent
 		 * function in the form of its strategy number, which is available
 		 * from the sk_strategy field, and its subtype from the sk_subtype
-		 * field.  Also, preserve sk_func.fn_collation which is the input
-		 * collation for the operator.
+		 * field.
 		 *
 		 * Next, if any of keys is a NULL and that key is not marked with
 		 * SK_SEARCHNULL/SK_SEARCHNOTNULL then nothing can be found (ie, we
@@ -181,10 +180,8 @@ gistrescan(PG_FUNCTION_ARGS)
 		for (i = 0; i < scan->numberOfKeys; i++)
 		{
 			ScanKey		skey = scan->keyData + i;
-			Oid			collation = skey->sk_func.fn_collation;
 
 			skey->sk_func = so->giststate->consistentFn[skey->sk_attno - 1];
-			skey->sk_func.fn_collation = collation;
 
 			if (skey->sk_flags & SK_ISNULL)
 			{
@@ -205,16 +202,13 @@ gistrescan(PG_FUNCTION_ARGS)
 		 * all comparisons. The original operator is passed to the Distance
 		 * function in the form of its strategy number, which is available
 		 * from the sk_strategy field, and its subtype from the sk_subtype
-		 * field.  Also, preserve sk_func.fn_collation which is the input
-		 * collation for the operator.
+		 * field.
 		 */
 		for (i = 0; i < scan->numberOfOrderBys; i++)
 		{
 			ScanKey		skey = scan->orderByData + i;
-			Oid			collation = skey->sk_func.fn_collation;
 
 			skey->sk_func = so->giststate->distanceFn[skey->sk_attno - 1];
-			skey->sk_func.fn_collation = collation;
 
 			/* Check we actually have a distance function ... */
 			if (!OidIsValid(skey->sk_func.fn_oid))