8 files changed, 158 insertions, 1 deletions
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index d167b496fce..a44b4cde0fa 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -16,6 +16,7 @@
 
 #include "executor/execdesc.h"
 #include "nodes/parsenodes.h"
+#include "nodes/relation.h"
 #include "utils/lockwaitpolicy.h"
 
 
@@ -103,7 +104,7 @@ extern PGDLLIMPORT ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook;
 extern void ExecReScan(PlanState *node);
 extern void ExecMarkPos(PlanState *node);
 extern void ExecRestrPos(PlanState *node);
-extern bool ExecSupportsMarkRestore(NodeTag plantype);
+extern bool ExecSupportsMarkRestore(Path *pathnode);
 extern bool ExecSupportsBackwardScan(Plan *node);
 extern bool ExecMaterializesOutput(NodeTag plantype);
 
diff --git a/src/include/executor/nodeCustom.h b/src/include/executor/nodeCustom.h
new file mode 100644
index 00000000000..1736d48bfaf
--- /dev/null
+++ b/src/include/executor/nodeCustom.h
@@ -0,0 +1,30 @@
+/* ------------------------------------------------------------------------
+ *
+ * nodeCustom.h
+ *
+ * prototypes for CustomScan nodes
+ *
+ * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * ------------------------------------------------------------------------
+ */
+#ifndef NODECUSTOM_H
+#define NODECUSTOM_H
+#include "nodes/plannodes.h"
+#include "nodes/execnodes.h"
+
+/*
+ * General executor code
+ */
+extern CustomScanState *ExecInitCustomScan(CustomScan *custom_scan,
+										   EState *estate, int eflags);
+extern TupleTableSlot *ExecCustomScan(CustomScanState *node);
+extern Node *MultiExecCustomScan(CustomScanState *node);
+extern void ExecEndCustomScan(CustomScanState *node);
+
+extern void ExecReScanCustomScan(CustomScanState *node);
+extern void ExecCustomMarkPos(CustomScanState *node);
+extern void ExecCustomRestrPos(CustomScanState *node);
+
+#endif	/* NODECUSTOM_H */
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 39d2c10bdfe..b72e605e4fe 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -19,6 +19,7 @@
 #include "executor/instrument.h"
 #include "nodes/params.h"
 #include "nodes/plannodes.h"
+#include "nodes/relation.h"
 #include "utils/reltrigger.h"
 #include "utils/sortsupport.h"
 #include "utils/tuplestore.h"
@@ -1504,6 +1505,45 @@ typedef struct ForeignScanState
 	void	   *fdw_state;		/* foreign-data wrapper can keep state here */
 } ForeignScanState;
 
+/* ----------------
+ * CustomScanState information
+ *
+ *		CustomScan nodes are used to execute custom code within executor.
+ * ----------------
+ */
+struct CustomExecMethods;
+struct ExplainState;	/* to avoid to include explain.h here */
+
+typedef struct CustomScanState
+{
+	ScanState	ss;
+	uint32		flags;	/* mask of CUSTOMPATH_* flags defined in relation.h*/
+	const struct CustomExecMethods *methods;
+} CustomScanState;
+
+typedef struct CustomExecMethods
+{
+	const char     *CustomName;
+
+	/* EXECUTOR methods */
+	void    (*BeginCustomScan)(CustomScanState *node,
+							   EState *estate,
+							   int eflags);
+	TupleTableSlot *(*ExecCustomScan)(CustomScanState *node);
+	void	(*EndCustomScan)(CustomScanState *node);
+	void	(*ReScanCustomScan)(CustomScanState *node);
+	void	(*MarkPosCustomScan)(CustomScanState *node);
+	void	(*RestrPosCustomScan)(CustomScanState *node);
+
+	/* EXPLAIN support */
+	void    (*ExplainCustomScan)(CustomScanState *node,
+								 List *ancestors,
+								 struct ExplainState *es);
+	Node   *(*GetSpecialCustomVar)(CustomScanState *node,
+								   Var *varnode,
+								   PlanState **child_ps);
+} CustomExecMethods;
+
 /* ----------------------------------------------------------------
  *				 Join State Information
  * ----------------------------------------------------------------
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 154d943d581..bc71fea78d0 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -62,6 +62,7 @@ typedef enum NodeTag
 	T_CteScan,
 	T_WorkTableScan,
 	T_ForeignScan,
+	T_CustomScan,
 	T_Join,
 	T_NestLoop,
 	T_MergeJoin,
@@ -107,6 +108,7 @@ typedef enum NodeTag
 	T_CteScanState,
 	T_WorkTableScanState,
 	T_ForeignScanState,
+	T_CustomScanState,
 	T_JoinState,
 	T_NestLoopState,
 	T_MergeJoinState,
@@ -224,6 +226,7 @@ typedef enum NodeTag
 	T_HashPath,
 	T_TidPath,
 	T_ForeignPath,
+	T_CustomPath,
 	T_AppendPath,
 	T_MergeAppendPath,
 	T_ResultPath,
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index fb02390da51..9dbb91cb90d 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -15,8 +15,10 @@
 #define PLANNODES_H
 
 #include "access/sdir.h"
+#include "lib/stringinfo.h"
 #include "nodes/bitmapset.h"
 #include "nodes/primnodes.h"
+#include "nodes/relation.h"
 #include "utils/lockwaitpolicy.h"
 
 
@@ -483,6 +485,33 @@ typedef struct ForeignScan
 	bool		fsSystemCol;	/* true if any "system column" is needed */
 } ForeignScan;
 
+/* ----------------
+ *     CustomScan node
+ * ----------------
+ */
+struct CustomScanMethods;
+
+typedef struct CustomScan
+{
+	Scan		scan;
+	uint32		flags;	/* mask of CUSTOMPATH_* flags defined in relation.h */
+	struct CustomScanMethods *methods;
+} CustomScan;
+
+typedef struct CustomScanMethods
+{
+	const char *CustomName;
+	void	   (*SetCustomScanRef)(struct PlannerInfo *root,
+								   CustomScan *cscan,
+								   int rtoffset);
+	void	   (*FinalizeCustomScan)(struct PlannerInfo *root,
+									 CustomScan *cscan,
+									 bool (*finalize_primnode)(),
+									 void *finalize_context);
+	Node	  *(*CreateCustomScanState)(CustomScan *cscan);
+	void	   (*TextOutCustomScan)(StringInfo str, const CustomScan *node);
+	CustomScan *(*CopyCustomScan)(const CustomScan *from);
+} CustomScanMethods;
 
 /*
  * ==========
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index f1a0504c0d4..05cfbcd2aa1 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -15,6 +15,7 @@
 #define RELATION_H
 
 #include "access/sdir.h"
+#include "lib/stringinfo.h"
 #include "nodes/params.h"
 #include "nodes/parsenodes.h"
 #include "storage/block.h"
@@ -884,6 +885,47 @@ typedef struct ForeignPath
 } ForeignPath;
 
 /*
+ * CustomPath represents a scan by some out-of-core extension.
+ *
+ * We provide a set of hooks here - which the provider must take care to
+ * set up correctly - to allow extensions to supply their own methods of
+ * scanning a relation.  For example, a provider might provide GPU
+ * acceleration, a cache-based scan, or some other kind of logic we haven't
+ * dreamed up yet.
+ *
+ * Core code should avoid assuming that the CustomPath is only as large as
+ * the structure declared here; providers are expected to make it the first
+ * element in a larger structure.
+ */
+
+struct CustomPathMethods;
+struct Plan;		/* not to include plannodes.h here */
+
+#define CUSTOMPATH_SUPPORT_BACKWARD_SCAN	0x0001
+#define CUSTOMPATH_SUPPORT_MARK_RESTORE		0x0002
+
+typedef struct CustomPath
+{
+	Path        path;
+	uint32		flags;
+	const struct CustomPathMethods *methods;
+} CustomPath;
+
+typedef struct CustomPathMethods
+{
+	const char *CustomName;
+	void	(*CreateCustomScanPath)(PlannerInfo *root,
+									RelOptInfo *baserel,
+									RangeTblEntry *rte);
+	struct Plan	*(*PlanCustomPath)(PlannerInfo *root,
+								   RelOptInfo *rel,
+								   CustomPath *best_path,
+								   List *tlist,
+								   List *clauses);
+	void    (*TextOutCustomPath)(StringInfo str, const CustomPath *node);
+} CustomPathMethods;
+
+/*
  * AppendPath represents an Append plan, ie, successive execution of
  * several member plans.
  *
diff --git a/src/include/optimizer/pathnode.h b/src/include/optimizer/pathnode.h
index 26b17f5f7af..2b67ae6187b 100644
--- a/src/include/optimizer/pathnode.h
+++ b/src/include/optimizer/pathnode.h
@@ -129,6 +129,15 @@ extern Path *reparameterize_path(PlannerInfo *root, Path *path,
 					double loop_count);
 
 /*
+ * Interface definition of custom-scan providers
+ */
+extern void register_custom_path_provider(CustomPathMethods *cpp_methods);
+
+extern void create_customscan_paths(PlannerInfo *root,
+									RelOptInfo *baserel,
+									RangeTblEntry *rte);
+
+/*
  * prototypes for relnode.c
  */
 extern void setup_simple_rel_arrays(PlannerInfo *root);
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 3fdc2cba0ed..c97c5777a07 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -86,6 +86,7 @@ extern ModifyTable *make_modifytable(PlannerInfo *root,
 				 List *withCheckOptionLists, List *returningLists,
 				 List *rowMarks, int epqParam);
 extern bool is_projection_capable_plan(Plan *plan);
+extern Node *replace_nestloop_params(PlannerInfo *root, Node *expr);
 
 /*
  * prototypes for plan/initsplan.c
@@ -130,6 +131,8 @@ extern bool query_is_distinct_for(Query *query, List *colnos, List *opids);
  */
 extern Plan *set_plan_references(PlannerInfo *root, Plan *plan);
 extern void fix_opfuncids(Node *node);
+extern Node *fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset);
+extern void fix_expr_common(PlannerInfo *root, Node *node);
 extern void set_opfuncid(OpExpr *opexpr);
 extern void set_sa_opfuncid(ScalarArrayOpExpr *opexpr);
 extern void record_plan_function_dependency(PlannerInfo *root, Oid funcid);