On 11/04/2016 22:53, Julien Rouhaud wrote:
> On 11/04/2016 17:44, Robert Haas wrote:
>>
>> We should probably add the number of workers actually obtained to the
>> EXPLAIN ANALYZE output. That's been requested before.
>>
>
> If it's not too late for 9.6, it would be very great.
>
Just in case I attach a patch to implement it. I'll add it to the next
commitfest.
--
Julien Rouhaud
http://dalibo.com - http://dalibo.org
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 713cd0e..8a1fbab 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1339,8 +1339,16 @@ ExplainNode(PlanState *planstate, List *ancestors,
if (plan->qual)
show_instrumentation_count("Rows
Removed by Filter", 1,
planstate, es);
- ExplainPropertyInteger("Number of Workers",
+ ExplainPropertyInteger("Number of Workers
planned",
gather->num_workers, es);
+ if (es->analyze)
+ {
+ int nworkers;
+
+ nworkers = ((GatherState *)
planstate)->nworkers_launched;
+ ExplainPropertyInteger("Number of
Workers launched",
+
nworkers, es);
+ }
if (gather->single_copy)
ExplainPropertyText("Single Copy",
gather->single_copy ? "true" : "false",
diff --git a/src/backend/executor/nodeGather.c
b/src/backend/executor/nodeGather.c
index 3f0ed69..3834ed6 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -166,6 +166,7 @@ ExecGather(GatherState *node)
*/
pcxt = node->pei->pcxt;
LaunchParallelWorkers(pcxt);
+ node->nworkers_launched = pcxt->nworkers_launched;
/* Set up tuple queue readers to read the results. */
if (pcxt->nworkers_launched > 0)
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index dbec07e..ee4e189 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1956,6 +1956,7 @@ typedef struct GatherState
struct ParallelExecutorInfo *pei;
int nreaders;
int nextreader;
+ int nworkers_launched;
struct TupleQueueReader **reader;
TupleTableSlot *funnel_slot;
bool need_to_scan_locally;
--
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