diff options
Diffstat (limited to 'src/backend/commands/explain.c')
| -rw-r--r-- | src/backend/commands/explain.c | 46 |
1 files changed, 17 insertions, 29 deletions
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index 455f54ef83f..f3c8da1e01b 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -2964,22 +2964,25 @@ show_hash_info(HashState *hashstate, ExplainState *es) HashInstrumentation hinstrument = {0}; /* + * Collect stats from the local process, even when it's a parallel query. * In a parallel query, the leader process may or may not have run the * hash join, and even if it did it may not have built a hash table due to * timing (if it started late it might have seen no tuples in the outer * relation and skipped building the hash table). Therefore we have to be * prepared to get instrumentation data from all participants. */ - if (hashstate->hashtable) - ExecHashGetInstrumentation(&hinstrument, hashstate->hashtable); + if (hashstate->hinstrument) + memcpy(&hinstrument, hashstate->hinstrument, + sizeof(HashInstrumentation)); /* * Merge results from workers. In the parallel-oblivious case, the * results from all participants should be identical, except where * participants didn't run the join at all so have no data. In the * parallel-aware case, we need to consider all the results. Each worker - * may have seen a different subset of batches and we want to find the - * highest memory usage for any one batch across all batches. + * may have seen a different subset of batches and we want to report the + * highest memory usage across all batches. We take the maxima of other + * values too, for the same reasons as in ExecHashAccumInstrumentation. */ if (hashstate->shared_info) { @@ -2990,31 +2993,16 @@ show_hash_info(HashState *hashstate, ExplainState *es) { HashInstrumentation *worker_hi = &shared_info->hinstrument[i]; - if (worker_hi->nbatch > 0) - { - /* - * Every participant should agree on the buckets, so to be - * sure we have a value we'll just overwrite each time. - */ - hinstrument.nbuckets = worker_hi->nbuckets; - hinstrument.nbuckets_original = worker_hi->nbuckets_original; - - /* - * Normally every participant should agree on the number of - * batches too, but it's possible for a backend that started - * late and missed the whole join not to have the final nbatch - * number. So we'll take the largest number. - */ - hinstrument.nbatch = Max(hinstrument.nbatch, worker_hi->nbatch); - hinstrument.nbatch_original = worker_hi->nbatch_original; - - /* - * In a parallel-aware hash join, for now we report the - * maximum peak memory reported by any worker. - */ - hinstrument.space_peak = - Max(hinstrument.space_peak, worker_hi->space_peak); - } + hinstrument.nbuckets = Max(hinstrument.nbuckets, + worker_hi->nbuckets); + hinstrument.nbuckets_original = Max(hinstrument.nbuckets_original, + worker_hi->nbuckets_original); + hinstrument.nbatch = Max(hinstrument.nbatch, + worker_hi->nbatch); + hinstrument.nbatch_original = Max(hinstrument.nbatch_original, + worker_hi->nbatch_original); + hinstrument.space_peak = Max(hinstrument.space_peak, + worker_hi->space_peak); } } |