pgsql-v9.3-writable-fdw-poc.v1.patch

 contrib/file_fdw/file_fdw.c            | 97 ++++++++++++++++++++++++++++++++++
 src/backend/executor/execMain.c        | 34 ++++++++++--
 src/backend/executor/nodeModifyTable.c | 65 +++++++++++++++++++++--
 src/backend/rewrite/rewriteHandler.c   |  3 +-
 src/include/foreign/fdwapi.h           | 19 +++++++
 src/include/nodes/execnodes.h          |  4 ++
 src/include/storage/itemptr.h          | 25 +++++++++
 7 files changed, 237 insertions(+), 10 deletions(-)

diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 7c7fedf..ef9f4b2 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -33,6 +33,7 @@
 #include "optimizer/var.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
+#include "utils/lsyscache.h"
 
 PG_MODULE_MAGIC;
 
@@ -96,6 +97,7 @@ typedef struct FileFdwExecutionState
 	char	   *filename;		/* file to read */
 	List	   *options;		/* merged COPY options, excluding filename */
 	CopyState	cstate;			/* state of reading file */
+	int			lineno;			/* pseudo ctid of the file */
 } FileFdwExecutionState;
 
 /*
@@ -130,6 +132,19 @@ static void fileEndForeignScan(ForeignScanState *node);
 static bool fileAnalyzeForeignTable(Relation relation,
 						AcquireSampleRowsFunc *func,
 						BlockNumber *totalpages);
+static void fileBeginForeignModify(CmdType operation,
+								   ResultRelInfo *resultRelInfo,
+								   EState *estate,
+								   Plan *subplan,
+								   int eflags);
+static void fileExecForeignInsert(ResultRelInfo *resultRelInfo,
+								  HeapTuple tuple);
+static void fileExecForeignDelete(ResultRelInfo *resultRelInfo,
+								  ItemPointer tupleid);
+static void fileExecForeignUpdate(ResultRelInfo *resultRelInfo,
+								  ItemPointer tupleid,
+								  HeapTuple tuple);
+static void fileEndForeignModify(ResultRelInfo *resultRelInfo);
 
 /*
  * Helper functions
@@ -169,6 +184,11 @@ file_fdw_handler(PG_FUNCTION_ARGS)
 	fdwroutine->ReScanForeignScan = fileReScanForeignScan;
 	fdwroutine->EndForeignScan = fileEndForeignScan;
 	fdwroutine->AnalyzeForeignTable = fileAnalyzeForeignTable;
+	fdwroutine->BeginForeignModify = fileBeginForeignModify;
+	fdwroutine->ExecForeignInsert = fileExecForeignInsert;
+	fdwroutine->ExecForeignDelete = fileExecForeignDelete;
+	fdwroutine->ExecForeignUpdate = fileExecForeignUpdate;
+	fdwroutine->EndForeignModify = fileEndForeignModify;
 
 	PG_RETURN_POINTER(fdwroutine);
 }
@@ -510,6 +530,36 @@ fileGetForeignPlan(PlannerInfo *root,
 				   List *scan_clauses)
 {
 	Index		scan_relid = baserel->relid;
+	ListCell   *cell;
+
+	/*
+	 * XXX - An evidence FDW module can know what kind of accesses are
+	 * requires on the target relation, if UPDATE, INSERT or DELETE.
+	 * It shall be also utilized to appropriate lock level on FDW
+	 * extensions that performs behalf on real RDBMS.
+	 */
+	if (root->parse->resultRelation == baserel->relid)
+	{
+		switch (root->parse->commandType)
+		{
+			case CMD_INSERT:
+				elog(INFO, "%s is the target relation of INSERT",
+					 get_rel_name(foreigntableid));
+				break;
+			case CMD_UPDATE:
+				elog(INFO, "%s is the target relation of UPDATE",
+					 get_rel_name(foreigntableid));
+				break;
+			case CMD_DELETE:
+				elog(INFO, "%s is the target relation of DELETE",
+                     get_rel_name(foreigntableid));
+				break;
+			default:
+				elog(INFO, "%s is the target relation of ??????",
+                     get_rel_name(foreigntableid));
+				break;
+		}
+	}
 
 	/*
 	 * We have no native ability to evaluate restriction clauses, so we just
@@ -598,6 +648,7 @@ fileBeginForeignScan(ForeignScanState *node, int eflags)
 	festate->filename = filename;
 	festate->options = options;
 	festate->cstate = cstate;
+	festate->lineno = 0;
 
 	node->fdw_state = (void *) festate;
 }
@@ -612,6 +663,7 @@ fileIterateForeignScan(ForeignScanState *node)
 {
 	FileFdwExecutionState *festate = (FileFdwExecutionState *) node->fdw_state;
 	TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
+	HeapTuple	tup;
 	bool		found;
 	ErrorContextCallback errcontext;
 
@@ -638,7 +690,12 @@ fileIterateForeignScan(ForeignScanState *node)
 						 slot->tts_values, slot->tts_isnull,
 						 NULL);
 	if (found)
+	{
 		ExecStoreVirtualTuple(slot);
+		tup = ExecMaterializeSlot(slot);
+		festate->lineno++;
+		PackPseudoItemPointer(&tup->t_self, festate->lineno);
+	}
 
 	/* Remove error callback. */
 	error_context_stack = errcontext.previous;
@@ -661,6 +718,7 @@ fileReScanForeignScan(ForeignScanState *node)
 									festate->filename,
 									NIL,
 									festate->options);
+	festate->lineno = 0;
 }
 
 /*
@@ -716,6 +774,45 @@ fileAnalyzeForeignTable(Relation relation,
 	return true;
 }
 
+static void
+fileBeginForeignModify(CmdType operation,
+					   ResultRelInfo *resultRelInfo,
+					   EState *estate,
+					   Plan *subplan,
+					   int eflags)
+{
+	elog(INFO, "fdw_file: BeginForeignModify method");
+}
+
+static void
+fileExecForeignInsert(ResultRelInfo *resultRelInfo, HeapTuple tuple)
+{
+	elog(INFO, "fdw_file: INSERT");
+}
+
+static void
+fileExecForeignDelete(ResultRelInfo *resultRelInfo,
+					  ItemPointer tupleid)
+{
+	elog(INFO, "fdw_file: DELETE (lineno = %lu)",
+		 (unsigned long) UnpackPseudoItemPointer(tupleid));
+}
+
+static void
+fileExecForeignUpdate(ResultRelInfo *resultRelInfo,
+					  ItemPointer tupleid,
+					  HeapTuple tuple)
+{
+	elog(INFO, "fdw_file: UPDATE (lineno = %lu)",
+		 (unsigned long) UnpackPseudoItemPointer(tupleid));
+}
+
+static void
+fileEndForeignModify(ResultRelInfo *resultRelInfo)
+{
+	elog(INFO, "fdw_file: EndForeignModify method");
+}
+
 /*
  * check_selective_binary_conversion
  *
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 440438b..7d20627 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -43,6 +43,7 @@
 #include "catalog/namespace.h"
 #include "commands/trigger.h"
 #include "executor/execdebug.h"
+#include "foreign/fdwapi.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "optimizer/clauses.h"
@@ -933,6 +934,7 @@ void
 CheckValidResultRel(Relation resultRel, CmdType operation)
 {
 	TriggerDesc *trigDesc = resultRel->trigdesc;
+	FdwRoutine	*fdwroutine;
 
 	switch (resultRel->rd_rel->relkind)
 	{
@@ -984,10 +986,34 @@ CheckValidResultRel(Relation resultRel, CmdType operation)
 			}
 			break;
 		case RELKIND_FOREIGN_TABLE:
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("cannot change foreign table \"%s\"",
-							RelationGetRelationName(resultRel))));
+			fdwroutine = GetFdwRoutineByRelId(RelationGetRelid(resultRel));
+			switch (operation)
+			{
+				case CMD_INSERT:
+					if (!fdwroutine || !fdwroutine->ExecForeignInsert)
+						ereport(ERROR,
+							(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+							 errmsg("cannot insert into foreign table \"%s\"",
+									RelationGetRelationName(resultRel))));
+					break;
+				case CMD_UPDATE:
+					if (!fdwroutine || !fdwroutine->ExecForeignUpdate)
+						ereport(ERROR,
+							(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+							 errmsg("cannot update foreign table \"\"",
+									RelationGetRelationName(resultRel))));
+					break;
+				case CMD_DELETE:
+					if (!fdwroutine || !fdwroutine->ExecForeignDelete)
+						ereport(ERROR,
+							(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+							 errmsg("cannot delete from foreign table \"\"",
+									RelationGetRelationName(resultRel))));
+					break;
+				default:
+					elog(ERROR, "unrecognized CmdType: %d", (int) operation);
+					break;
+			}
 			break;
 		default:
 			ereport(ERROR,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index a7bce75..b2fc516 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -41,6 +41,7 @@
 #include "commands/trigger.h"
 #include "executor/executor.h"
 #include "executor/nodeModifyTable.h"
+#include "foreign/fdwapi.h"
 #include "miscadmin.h"
 #include "nodes/nodeFuncs.h"
 #include "storage/bufmgr.h"
@@ -224,6 +225,14 @@ ExecInsert(TupleTableSlot *slot,
 
 		newId = InvalidOid;
 	}
+	else if (resultRelInfo->ri_fdwroutine)
+	{
+		FdwRoutine *fdwroutine = resultRelInfo->ri_fdwroutine;
+
+		fdwroutine->ExecForeignInsert(resultRelInfo, tuple);
+
+		newId = InvalidOid;
+	}
 	else
 	{
 		/*
@@ -334,6 +343,12 @@ ExecDelete(ItemPointer tupleid,
 		if (!dodelete)			/* "do nothing" */
 			return NULL;
 	}
+	else if (resultRelInfo->ri_fdwroutine)
+	{
+		FdwRoutine *fdwroutine = resultRelInfo->ri_fdwroutine;
+
+		fdwroutine->ExecForeignDelete(resultRelInfo, tupleid);
+	}
 	else
 	{
 		/*
@@ -538,6 +553,12 @@ ExecUpdate(ItemPointer tupleid,
 		/* trigger might have changed tuple */
 		tuple = ExecMaterializeSlot(slot);
 	}
+	else if (resultRelInfo->ri_fdwroutine)
+	{
+		FdwRoutine *fdwroutine = resultRelInfo->ri_fdwroutine;
+
+		fdwroutine->ExecForeignUpdate(resultRelInfo, tupleid, tuple);
+	}
 	else
 	{
 		/*
@@ -805,10 +826,12 @@ ExecModifyTable(ModifyTableState *node)
 			 */
 			if (operation == CMD_UPDATE || operation == CMD_DELETE)
 			{
+				Relation	rel = resultRelInfo->ri_RelationDesc;
 				Datum		datum;
 				bool		isNull;
 
-				if (resultRelInfo->ri_RelationDesc->rd_rel->relkind == RELKIND_RELATION)
+				if (RelationGetForm(rel)->relkind == RELKIND_RELATION ||
+					RelationGetForm(rel)->relkind == RELKIND_FOREIGN_TABLE)
 				{
 					datum = ExecGetJunkAttribute(slot,
 												 junkfilter->jf_junkAttNo,
@@ -964,6 +987,22 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		estate->es_result_relation_info = resultRelInfo;
 		mtstate->mt_plans[i] = ExecInitNode(subplan, estate, eflags);
 
+		/*
+		 * Also tells FDW extensions to init the plan for this result rel
+		 */
+		if (RelationGetForm(resultRelInfo->ri_RelationDesc)->relkind == RELKIND_FOREIGN_TABLE)
+		{
+			Oid		relid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
+			FdwRoutine *fdwroutine = GetFdwRoutineByRelId(relid);
+
+			Assert(fdwroutine != NULL);
+			resultRelInfo->ri_fdwroutine = fdwroutine;
+			resultRelInfo->ri_fdw_state = NULL;
+
+			if (fdwroutine->BeginForeignModify)
+				fdwroutine->BeginForeignModify(operation, resultRelInfo,
+											   estate, subplan, eflags);
+		}
 		resultRelInfo++;
 		i++;
 	}
@@ -1104,21 +1143,22 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 			resultRelInfo = mtstate->resultRelInfo;
 			for (i = 0; i < nplans; i++)
 			{
+				Relation	rel = resultRelInfo->ri_RelationDesc;
 				JunkFilter *j;
 
 				subplan = mtstate->mt_plans[i]->plan;
 				if (operation == CMD_INSERT || operation == CMD_UPDATE)
-					ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc,
-										subplan->targetlist);
+					ExecCheckPlanOutput(rel, subplan->targetlist);
 
 				j = ExecInitJunkFilter(subplan->targetlist,
-							resultRelInfo->ri_RelationDesc->rd_att->tdhasoid,
+									   RelationGetDescr(rel)->tdhasoid,
 									   ExecInitExtraTupleSlot(estate));
 
 				if (operation == CMD_UPDATE || operation == CMD_DELETE)
 				{
 					/* For UPDATE/DELETE, find the appropriate junk attr now */
-					if (resultRelInfo->ri_RelationDesc->rd_rel->relkind == RELKIND_RELATION)
+					if (RelationGetForm(rel)->relkind == RELKIND_RELATION ||
+						RelationGetForm(rel)->relkind == RELKIND_FOREIGN_TABLE)
 					{
 						j->jf_junkAttNo = ExecFindJunkAttribute(j, "ctid");
 						if (!AttributeNumberIsValid(j->jf_junkAttNo))
@@ -1181,6 +1221,21 @@ ExecEndModifyTable(ModifyTableState *node)
 {
 	int			i;
 
+	/* Let the FDW shut dowm */
+	for (i=0; i < node->ps.state->es_num_result_relations; i++)
+	{
+		ResultRelInfo  *resultRelInfo
+			= &node->ps.state->es_result_relations[i];
+
+		if (resultRelInfo->ri_fdwroutine)
+		{
+			FdwRoutine *fdwroutine = resultRelInfo->ri_fdwroutine;
+
+			if (fdwroutine->EndForeignModify)
+				fdwroutine->EndForeignModify(resultRelInfo);
+		}
+	}
+
 	/*
 	 * Free the exprcontext
 	 */
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 8f75948..f461b87 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -1166,7 +1166,8 @@ rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
 	const char *attrname;
 	TargetEntry *tle;
 
-	if (target_relation->rd_rel->relkind == RELKIND_RELATION)
+	if (target_relation->rd_rel->relkind == RELKIND_RELATION ||
+		target_relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
 	{
 		/*
 		 * Emit CTID so that executor can find the row to update or delete.
diff --git a/src/include/foreign/fdwapi.h b/src/include/foreign/fdwapi.h
index 721cd25..252d505 100644
--- a/src/include/foreign/fdwapi.h
+++ b/src/include/foreign/fdwapi.h
@@ -59,6 +59,20 @@ typedef bool (*AnalyzeForeignTable_function) (Relation relation,
 												 AcquireSampleRowsFunc *func,
 													BlockNumber *totalpages);
 
+typedef void (*BeginForeignModify_function) (CmdType operation,
+											 ResultRelInfo *resultRelInfo,
+											 EState *estate,
+											 Plan *subplan,
+											 int eflags);
+typedef void (*ExecForeignInsert_function) (ResultRelInfo *resultRelInfo,
+											HeapTuple tuple);
+typedef void (*ExecForeignDelete_function) (ResultRelInfo *resultRelInfo,
+											ItemPointer tupleid);
+typedef void (*ExecForeignUpdate_function) (ResultRelInfo *resultRelInfo,
+											ItemPointer tupleid,
+											HeapTuple tuple);
+typedef void (*EndForeignModify_function) (ResultRelInfo *resultRelInfo);
+
 /*
  * FdwRoutine is the struct returned by a foreign-data wrapper's handler
  * function.  It provides pointers to the callback functions needed by the
@@ -90,6 +104,11 @@ typedef struct FdwRoutine
 	 * not provided.
 	 */
 	AnalyzeForeignTable_function AnalyzeForeignTable;
+	BeginForeignModify_function	BeginForeignModify;
+	ExecForeignInsert_function ExecForeignInsert;
+	ExecForeignDelete_function ExecForeignDelete;
+	ExecForeignUpdate_function ExecForeignUpdate;
+	EndForeignModify_function EndForeignModify;
 } FdwRoutine;
 
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index fec07b8..db5b79b 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -303,6 +303,8 @@ typedef struct JunkFilter
  *		ConstraintExprs			array of constraint-checking expr states
  *		junkFilter				for removing junk attributes from tuples
  *		projectReturning		for computing a RETURNING list
+ *		fdwroutine				FDW callbacks if foreign table
+ *		fdw_state				opaque state of FDW module, or NULL
  * ----------------
  */
 typedef struct ResultRelInfo
@@ -320,6 +322,8 @@ typedef struct ResultRelInfo
 	List	  **ri_ConstraintExprs;
 	JunkFilter *ri_junkFilter;
 	ProjectionInfo *ri_projectReturning;
+	struct FdwRoutine  *ri_fdwroutine;
+	void	   *ri_fdw_state;
 } ResultRelInfo;
 
 /* ----------------
diff --git a/src/include/storage/itemptr.h b/src/include/storage/itemptr.h
index 331812b..8fdee45 100644
--- a/src/include/storage/itemptr.h
+++ b/src/include/storage/itemptr.h
@@ -135,6 +135,31 @@ typedef ItemPointerData *ItemPointer;
 	(pointer)->ip_posid = InvalidOffsetNumber \
 )
 
+/*
+ * PackPseudoItemPointer
+ *		Pack a pseudo item pointer of foreign table
+ */
+#define PackPseudoItemPointer(pointer,value)							\
+	do {																\
+		AssertMacro((value) < (1UL << (8 * (sizeof(BlockIdData) +		\
+											sizeof(OffsetNumber)))));	\
+		BlockIdSet(&((pointer)->ip_blkid),								\
+				   (value) >> (8 * sizeof(OffsetNumber)));				\
+		(pointer)->ip_posid =											\
+			(value) & ((1 << (8 * sizeof(OffsetNumber))) - 1);			\
+	} while(0)
+
+/*
+ * UnpackPseudoItemPointer
+ *		Unpack a pseudo item pointer of foreign table
+ */
+#define UnpackPseudoItemPointer(pointer)					\
+	(														\
+		(BlockIdGetBlockNumber(&(pointer)->ip_blkid)		\
+		 << (8 * sizeof(OffsetNumber)))						\
+		| ((pointer)->ip_posid)								\
+	)
+
 /* ----------------
  *		externs
  * ----------------