Parallel executor support.

This code provides infrastructure for a parallel leader to start up
parallel workers to execute subtrees of the plan tree being executed
in the master.  User-supplied parameters from ParamListInfo are passed
down, but PARAM_EXEC parameters are not.  Various other constructs,
such as initplans, subplans, and CTEs, are also not currently shared.
Nevertheless, there's enough here to support a basic implementation of
parallel query, and we can lift some of the current restrictions as
needed.

Amit Kapila and Robert Haas

6 files changed, 57 insertions, 0 deletions

diff --git a/src/include/executor/execParallel.h b/src/include/executor/execParallel.h
new file mode 100644
index 00000000000..4fc797ad982
--- /dev/null
+++ b/src/include/executor/execParallel.h
@@ -0,0 +1,36 @@
+/*--------------------------------------------------------------------
+ * execParallel.h
+ *		POSTGRES parallel execution interface
+ *
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *		src/include/executor/execParallel.h
+ *--------------------------------------------------------------------
+ */
+
+#ifndef EXECPARALLEL_H
+#define EXECPARALLEL_H
+
+#include "access/parallel.h"
+#include "nodes/execnodes.h"
+#include "nodes/parsenodes.h"
+#include "nodes/plannodes.h"
+
+typedef struct SharedExecutorInstrumentation SharedExecutorInstrumentation;
+
+typedef struct ParallelExecutorInfo
+{
+	PlanState *planstate;
+	ParallelContext *pcxt;
+	BufferUsage *buffer_usage;
+	SharedExecutorInstrumentation *instrumentation;
+	shm_mq_handle **tqueue;
+}	ParallelExecutorInfo;
+
+extern ParallelExecutorInfo *ExecInitParallelPlan(PlanState *planstate,
+					 EState *estate, int nworkers);
+extern void ExecParallelFinish(ParallelExecutorInfo *pei);
+
+#endif   /* EXECPARALLEL_H */
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index c9a2129c7ae..f28e56ce48c 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -66,8 +66,13 @@ typedef struct Instrumentation
 extern PGDLLIMPORT BufferUsage pgBufferUsage;
 
 extern Instrumentation *InstrAlloc(int n, int instrument_options);
+extern void InstrInit(Instrumentation *instr, int instrument_options);
 extern void InstrStartNode(Instrumentation *instr);
 extern void InstrStopNode(Instrumentation *instr, double nTuples);
 extern void InstrEndLoop(Instrumentation *instr);
+extern void InstrAggNode(Instrumentation *dst, Instrumentation *add);
+extern void InstrStartParallelQuery(void);
+extern void InstrEndParallelQuery(BufferUsage *result);
+extern void InstrAccumParallelQuery(BufferUsage *result);
 
 #endif   /* INSTRUMENT_H */
diff --git a/src/include/nodes/params.h b/src/include/nodes/params.h
index a0f7dd0c555..83bebde69d4 100644
--- a/src/include/nodes/params.h
+++ b/src/include/nodes/params.h
@@ -102,5 +102,8 @@ typedef struct ParamExecData
 
 /* Functions found in src/backend/nodes/params.c */
 extern ParamListInfo copyParamList(ParamListInfo from);
+extern Size EstimateParamListSpace(ParamListInfo paramLI);
+extern void SerializeParamList(ParamListInfo paramLI, char **start_address);
+extern ParamListInfo RestoreParamList(char **start_address);
 
 #endif   /* PARAMS_H */
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index cc259f1f674..1e2d2bbaa10 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -111,6 +111,7 @@ typedef struct Plan
 	/*
 	 * Common structural data for all Plan types.
 	 */
+	int			plan_node_id;	/* unique across entire final plan tree */
 	List	   *targetlist;		/* target list to be computed at this node */
 	List	   *qual;			/* implicitly-ANDed qual conditions */
 	struct Plan *lefttree;		/* input plan tree(s) */
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 79bed3316bb..961b5d17cfb 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -99,6 +99,8 @@ typedef struct PlannerGlobal
 
 	Index		lastRowMarkId;	/* highest PlanRowMark ID assigned */
 
+	int			lastPlanNodeId;	/* highest plan node ID assigned */
+
 	bool		transientPlan;	/* redo plan when TransactionXmin changes? */
 
 	bool		hasRowSecurity; /* row security applied? */
diff --git a/src/include/utils/datum.h b/src/include/utils/datum.h
index c572f790a50..e9d4be5c4ba 100644
--- a/src/include/utils/datum.h
+++ b/src/include/utils/datum.h
@@ -46,4 +46,14 @@ extern Datum datumTransfer(Datum value, bool typByVal, int typLen);
 extern bool datumIsEqual(Datum value1, Datum value2,
 			 bool typByVal, int typLen);
 
+/*
+ * Serialize and restore datums so that we can transfer them to parallel
+ * workers.
+ */
+extern Size datumEstimateSpace(Datum value, bool isnull, bool typByVal,
+				   int typLen);
+extern void datumSerialize(Datum value, bool isnull, bool typByVal,
+			   int typLen, char **start_address);
+extern Datum datumRestore(char **start_address, bool *isnull);
+
 #endif   /* DATUM_H */