4 files changed, 84 insertions, 3 deletions

diff --git a/src/include/utils/plancache.h b/src/include/utils/plancache.h
index 84952d56e7..48d4ac94b2 100644
--- a/src/include/utils/plancache.h
+++ b/src/include/utils/plancache.h
@@ -17,6 +17,7 @@
 
 #include "access/tupdesc.h"
 #include "nodes/params.h"
+#include "utils/queryenvironment.h"
 
 /* Forward declaration, to avoid including parsenodes.h here */
 struct RawStmt;
@@ -148,7 +149,8 @@ extern void ResetPlanCache(void);
 
 extern CachedPlanSource *CreateCachedPlan(struct RawStmt *raw_parse_tree,
 				 const char *query_string,
-				 const char *commandTag);
+				 const char *commandTag,
+				 QueryEnvironment *queryEnv);
 extern CachedPlanSource *CreateOneShotCachedPlan(struct RawStmt *raw_parse_tree,
 						const char *query_string,
 						const char *commandTag);
@@ -172,11 +174,13 @@ extern CachedPlanSource *CopyCachedPlan(CachedPlanSource *plansource);
 
 extern bool CachedPlanIsValid(CachedPlanSource *plansource);
 
-extern List *CachedPlanGetTargetList(CachedPlanSource *plansource);
+extern List *CachedPlanGetTargetList(CachedPlanSource *plansource,
+							QueryEnvironment *queryEnv);
 
 extern CachedPlan *GetCachedPlan(CachedPlanSource *plansource,
 			  ParamListInfo boundParams,
-			  bool useResOwner);
+			  bool useResOwner,
+			  QueryEnvironment *queryEnv);
 extern void ReleaseCachedPlan(CachedPlan *plan, bool useResOwner);
 
 #endif   /* PLANCACHE_H */
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index e7c5a8bd09..ef3898c98c 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -137,6 +137,7 @@ typedef struct PortalData
 	CachedPlan *cplan;			/* CachedPlan, if stmts are from one */
 
 	ParamListInfo portalParams; /* params to pass to query */
+	QueryEnvironment *queryEnv; /* environment for query */
 
 	/* Features/options */
 	PortalStrategy strategy;	/* see above */
diff --git a/src/include/utils/queryenvironment.h b/src/include/utils/queryenvironment.h
new file mode 100644
index 0000000000..b4f65a1976
--- /dev/null
+++ b/src/include/utils/queryenvironment.h
@@ -0,0 +1,74 @@
+/*-------------------------------------------------------------------------
+ *
+ * queryenvironment.h
+ *	  Access to functions to mutate the query environment and retrieve the
+ *	  actual data related to entries (if any).
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/utils/queryenvironment.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef QUERYENVIRONMENT_H
+#define QUERYENVIRONMENT_H
+
+#include "access/tupdesc.h"
+
+
+typedef enum EphemeralNameRelationType
+{
+	ENR_NAMED_TUPLESTORE		/* named tuplestore relation; e.g., deltas */
+} EphemeralNameRelationType;
+
+/*
+ * Some ephemeral named relations must match some relation (e.g., trigger
+ * transition tables), so to properly handle cached plans and DDL, we should
+ * carry the OID of that relation.  In other cases an ENR might be independent
+ * of any relation which is stored in the system catalogs, so we need to be
+ * able to directly store the TupleDesc.  We never need both.
+ */
+typedef struct EphemeralNamedRelationMetadataData
+{
+	char			   *name;		/* name used to identify the relation */
+
+	/* only one of the next two fields should be used */
+	Oid					reliddesc;	/* oid of relation to get tupdesc */
+	TupleDesc			tupdesc;	/* description of result rows */
+
+	EphemeralNameRelationType enrtype;	/* to identify type of relation */
+	double				enrtuples;	/* estimated number of tuples */
+} EphemeralNamedRelationMetadataData;
+
+typedef EphemeralNamedRelationMetadataData *EphemeralNamedRelationMetadata;
+
+/*
+ * Ephemeral Named Relation data; used for parsing named relations not in the
+ * catalog, like transition tables in AFTER triggers.
+ */
+typedef struct EphemeralNamedRelationData
+{
+	EphemeralNamedRelationMetadataData	md;
+	void	   *reldata;		/* structure for execution-time access to data */
+} EphemeralNamedRelationData;
+
+typedef EphemeralNamedRelationData *EphemeralNamedRelation;
+
+/*
+ * This is an opaque structure outside of queryenvironment.c itself.  The
+ * intention is to be able to change the implementation or add new context
+ * features without needing to change existing code for use of existing
+ * features.
+ */
+typedef struct QueryEnvironment QueryEnvironment;
+
+
+extern QueryEnvironment *create_queryEnv(void);
+extern EphemeralNamedRelationMetadata get_visible_ENR_metadata(QueryEnvironment *queryEnv, const char *refname);
+extern void register_ENR(QueryEnvironment *queryEnv, EphemeralNamedRelation enr);
+extern void unregister_ENR(QueryEnvironment *queryEnv, const char *name);
+extern EphemeralNamedRelation get_ENR(QueryEnvironment *queryEnv, const char *name);
+extern TupleDesc ENRMetadataGetTupDesc(EphemeralNamedRelationMetadata enrmd);
+
+#endif   /* QUERYENVIRONMENT_H */
diff --git a/src/include/utils/tuplestore.h b/src/include/utils/tuplestore.h
index a52a547037..b31ede882b 100644
--- a/src/include/utils/tuplestore.h
+++ b/src/include/utils/tuplestore.h
@@ -78,6 +78,8 @@ extern bool tuplestore_advance(Tuplestorestate *state, bool forward);
 extern bool tuplestore_skiptuples(Tuplestorestate *state,
 					  int64 ntuples, bool forward);
 
+extern int64 tuplestore_tuple_count(Tuplestorestate *state);
+
 extern bool tuplestore_ateof(Tuplestorestate *state);
 
 extern void tuplestore_rescan(Tuplestorestate *state);