From: Shigeru Hanada <hanada@metrosystems.co.jp>
Date: Wed, 17 Nov 2010 09:45:45 +0000 (+0900)
Subject: Add GetFdwRoutineByRelId(), which retrieves FdwRoutine object from
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=47403390ffe188b5f4d87b906c60cebe6229d4af;p=users%2Fhanada%2Fpostgres.git

Add GetFdwRoutineByRelId(), which retrieves FdwRoutine object from
oid of the foreign table directly, to avoid creating useless objects.
---

diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 0458a2fc48..bbf04759fc 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -38,7 +38,7 @@ extern Datum postgresql_fdw_validator(PG_FUNCTION_ARGS);
 
 
 /*
- * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
+ * GetForeignDataWrapper - look up the foreign-data wrapper by OID.
  */
 ForeignDataWrapper *
 GetForeignDataWrapper(Oid fdwid)
@@ -485,6 +485,10 @@ GetForeignTable(Oid relid)
 	return ft;
 }
 
+/*
+ * GetFdwRoutine - look up the handler of the foreign-data wrapper by OID and
+ * retrieve FdwRoutine.
+ */
 FdwRoutine *
 GetFdwRoutine(Oid fdwhandler)
 {
@@ -507,6 +511,62 @@ GetFdwRoutine(Oid fdwhandler)
 	return routine;
 }
 
+/*
+ * GetFdwRoutineByRelId - look up the handler of the foreign-data wrapper by
+ * OID of the foreign table and retrieve FdwRoutine.
+ */
+FdwRoutine *
+GetFdwRoutineByRelId(Oid relid)
+{
+	HeapTuple				tp;
+	Form_pg_foreign_data_wrapper fdwform;
+	Form_pg_foreign_server	serverform;
+	Form_pg_foreign_table	tableform;
+	Oid						serverid;
+	Oid						fdwid;
+	Oid						fdwhandler;
+	FmgrInfo				flinfo;
+	FunctionCallInfoData	fcinfo;
+	Datum					result;
+	FdwRoutine			   *routine;
+
+	/* Get function OID for the foreign table. */
+	tp = SearchSysCache1(FOREIGNTABLEREL, ObjectIdGetDatum(relid));
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for foreign table %u", relid);
+	tableform = (Form_pg_foreign_table) GETSTRUCT(tp);
+	serverid = tableform->ftserver;
+	ReleaseSysCache(tp);
+
+	tp = SearchSysCache1(FOREIGNSERVEROID, ObjectIdGetDatum(serverid));
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for foreign server %u", serverid);
+	serverform = (Form_pg_foreign_server) GETSTRUCT(tp);
+	fdwid = serverform->srvfdw;
+	ReleaseSysCache(tp);
+
+	tp = SearchSysCache1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(fdwid));
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for foreign-data wrapper %u", fdwid);
+	fdwform = (Form_pg_foreign_data_wrapper) GETSTRUCT(tp);
+	fdwhandler = fdwform->fdwhandler;
+	ReleaseSysCache(tp);
+
+	/* Get FdwRoutine by invoking fdwhandler function. */
+	fmgr_info(fdwhandler, &flinfo);
+	InitFunctionCallInfoData(fcinfo, &flinfo, 0, NULL, NULL);
+	result = FunctionCallInvoke(&fcinfo);
+
+	if (fcinfo.isnull ||
+		(routine = (FdwRoutine *) DatumGetPointer(result)) == NULL)
+	{
+		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);
+		routine = NULL;	/* keep compiler quiet */
+	}
+
+	return routine;
+}
+
 /*
  * Determine the relation is a foreign table.
  */
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 6a8faf8bde..bc416218f6 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -1030,9 +1030,6 @@ cost_foreignscan(ForeignPath *path, PlannerInfo *root,
 			 RelOptInfo *baserel)
 {
 	RangeTblEntry  *rte;
-	ForeignTable   *table;
-	ForeignServer  *server;
-	ForeignDataWrapper  *wrapper;
 	FdwRoutine	   *routine;
 
 	/* Should only be applied to base relations */
@@ -1041,11 +1038,7 @@ cost_foreignscan(ForeignPath *path, PlannerInfo *root,
 
 	/* Leave estimation of the costs to the wrapper handler */
 	rte = planner_rt_fetch(baserel->relid, root);
-	table = GetForeignTable(rte->relid);
-	server = GetForeignServer(table->serverid);
-	wrapper = GetForeignDataWrapper(server->fdwid);
-	routine = GetFdwRoutine(wrapper->fdwhandler);
-
+	routine = GetFdwRoutineByRelId(rte->relid);
 	if (routine->EstimateCosts != NULL)
 		routine->EstimateCosts(path, root, baserel);
 }
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index 743a36f2e4..ef3fe9e312 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -84,6 +84,7 @@ extern ForeignDataWrapper *GetForeignDataWrapperByName(const char *name,
 extern Oid	GetForeignDataWrapperOidByName(const char *name, bool missing_ok);
 extern ForeignTable *GetForeignTable(Oid relid);
 extern FdwRoutine *GetFdwRoutine(Oid fdwhandler);
+extern FdwRoutine *GetFdwRoutineByRelId(Oid relid);
 extern bool IsForeignTable(Oid relid);
 extern Oid GetFdwValidator(Oid relid);
 extern List *GetGenericOptionsPerColumn(Oid relid, int2 attnum);