diff options
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 8 | ||||
| -rw-r--r-- | src/backend/executor/nodeAppend.c | 18 |
2 files changed, 20 insertions, 6 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index c590f374c67..e201b5404e6 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -5835,7 +5835,10 @@ merge_fdw_options(PgFdwRelationInfo *fpinfo, /* * We'll prefer to consider this join async-capable if any table from - * either side of the join is considered async-capable. + * either side of the join is considered async-capable. This would be + * reasonable because in that case the foreign server would have its + * own resources to scan that table asynchronously, and the join could + * also be computed asynchronously using the resources. */ fpinfo->async_capable = fpinfo_o->async_capable || fpinfo_i->async_capable; @@ -6893,6 +6896,9 @@ produce_tuple_asynchronously(AsyncRequest *areq, bool fetch) /* * Begin an asynchronous data fetch. * + * Note: this function assumes there is no currently-in-progress asynchronous + * data fetch. + * * Note: fetch_more_data must be called to fetch the result. */ static void diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c index c2527572686..3c1f12adafb 100644 --- a/src/backend/executor/nodeAppend.c +++ b/src/backend/executor/nodeAppend.c @@ -952,7 +952,10 @@ ExecAppendAsyncRequest(AppendState *node, TupleTableSlot **result) /* Nothing to do if there are no async subplans needing a new request. */ if (bms_is_empty(node->as_needrequest)) + { + Assert(node->as_nasyncresults == 0); return false; + } /* * If there are any asynchronously-generated results that have not yet @@ -998,17 +1001,16 @@ ExecAppendAsyncRequest(AppendState *node, TupleTableSlot **result) static void ExecAppendAsyncEventWait(AppendState *node) { + int nevents = node->as_nasyncplans + 1; long timeout = node->as_syncdone ? -1 : 0; WaitEvent occurred_event[EVENT_BUFFER_SIZE]; int noccurred; - int nevents; int i; /* We should never be called when there are no valid async subplans. */ Assert(node->as_nasyncremain > 0); - node->as_eventset = CreateWaitEventSet(CurrentMemoryContext, - node->as_nasyncplans + 1); + node->as_eventset = CreateWaitEventSet(CurrentMemoryContext, nevents); AddWaitEventToSet(node->as_eventset, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET, NULL, NULL); @@ -1022,8 +1024,14 @@ ExecAppendAsyncEventWait(AppendState *node) ExecAsyncConfigureWait(areq); } - /* Wait for at least one event to occur. */ - nevents = Min(node->as_nasyncplans + 1, EVENT_BUFFER_SIZE); + /* We wait on at most EVENT_BUFFER_SIZE events. */ + if (nevents > EVENT_BUFFER_SIZE) + nevents = EVENT_BUFFER_SIZE; + + /* + * If the timeout is -1, wait until at least one event occurs. If the + * timeout is 0, poll for events, but do not wait at all. + */ noccurred = WaitEventSetWait(node->as_eventset, timeout, occurred_event, nevents, WAIT_EVENT_APPEND_READY); FreeWaitEventSet(node->as_eventset); |