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| author | Etsuro Fujita <efujita@postgresql.org> | 2021-04-23 12:00:00 +0900 |
|---|---|---|
| committer | Etsuro Fujita <efujita@postgresql.org> | 2021-04-23 12:00:00 +0900 |
| commit | bb684c82f73316b88f9bcb321128a4347b5206fe (patch) | |
| tree | 510fc2a7ece07b3df91815242e857aa0d3974a4b /contrib/postgres_fdw/postgres_fdw.c | |
| parent | d479d00285255d422a2b38f1cfaa35808968a08c (diff) | |
| download | postgresql-bb684c82f73316b88f9bcb321128a4347b5206fe.tar.gz postgresql-bb684c82f73316b88f9bcb321128a4347b5206fe.zip | |
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
Diffstat (limited to 'contrib/postgres_fdw/postgres_fdw.c')
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 8 |
1 files changed, 7 insertions, 1 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 |