From bb684c82f73316b88f9bcb321128a4347b5206fe Mon Sep 17 00:00:00 2001 From: Etsuro Fujita Date: Fri, 23 Apr 2021 12:00:00 +0900 Subject: Minor code cleanup in asynchronous execution support. This is cleanup for commit 27e1f1456: * ExecAppendAsyncEventWait(), which was modified a bit further by commit a8af856d3, duplicated the same nevents calculation. Simplify the code a little bit to avoid the duplication. Update comments there. * Add an assertion to ExecAppendAsyncRequest(). * Update a comment about merging the async_capable options from input relations in merge_fdw_options(), per complaint from Kyotaro Horiguchi. * Add a comment for fetch_more_data_begin(). Author: Etsuro Fujita Discussion: https://postgr.es/m/CAPmGK1637W30Wx3MnrReewhafn6F_0J76mrJGoFXFnpPq4QfvA%40mail.gmail.com --- contrib/postgres_fdw/postgres_fdw.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'contrib/postgres_fdw/postgres_fdw.c') 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 -- cgit v1.2.3