Allow EXPLAIN (ANALYZE, VERBOSE) to display per-worker statistics.

The original parallel sequential scan commit included only very limited
changes to the EXPLAIN output.  Aggregated totals from all workers were
displayed, but there was no way to see what each individual worker did
or to distinguish the effort made by the workers from the effort made by
the leader.

Per a gripe by Thom Brown (and maybe others).  Patch by me, reviewed
by Amit Kapila.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index f28e56ce48c..52d3c818282 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -63,6 +63,12 @@ typedef struct Instrumentation
 	BufferUsage bufusage;		/* Total buffer usage */
 } Instrumentation;
 
+typedef struct WorkerInstrumentation
+{
+	int			num_workers;	/* # of structures that follow */
+	Instrumentation instrument[FLEXIBLE_ARRAY_MEMBER];
+} WorkerInstrumentation;
+
 extern PGDLLIMPORT BufferUsage pgBufferUsage;
 
 extern Instrumentation *InstrAlloc(int n, int instrument_options);