EXPLAIN ANALYZE feature to measure and show actual runtimes and tuple

counts alongside the planner's estimates.  By Martijn van Oosterhout,
with some further work by Tom Lane.

src/include/executor/instrument.h

@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * instrument.h
+ *	  definitions for run-time statistics collection
+ *
+ *
+ * Copyright (c) 2001, PostgreSQL Global Development Group
+ *
+ * $Id: instrument.h,v 1.1 2001/09/18 01:59:06 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef INSTRUMENT_H
+#define INSTRUMENT_H
+
+#include <sys/time.h>
+
+
+typedef struct Instrumentation
+{
+	/* Info about current plan cycle: */
+	bool running;				/* TRUE if we've completed first tuple */
+	struct timeval starttime;	/* Start time of current iteration of node */
+	struct timeval counter;		/* Accumulates runtime for this node */
+	double firsttuple;			/* Time for first tuple of this cycle */
+	double tuplecount;			/* Tuples so far this cycle */
+	/* Accumulated statistics across all completed cycles: */
+	double startup;				/* Total startup time (in seconds) */
+	double total;				/* Total total time (in seconds) */
+	double ntuples;				/* Total tuples produced */
+	double nloops;				/* # of run cycles for this node */
+} Instrumentation;
+
+extern Instrumentation *InstrAlloc(void);
+extern void InstrStartNode(Instrumentation *instr);
+extern void InstrStopNode(Instrumentation *instr, bool returnedTuple);
+extern void InstrEndLoop(Instrumentation *instr);
+
+#endif /* INSTRUMENT_H */