On 2016/04/19 13:59, Michael Paquier wrote:
On Tue, Apr 19, 2016 at 1:14 PM, Etsuro Fujita
<fujita.ets...@lab.ntt.co.jp> wrote:
What do you think about that?
+ /* Wait for the result */
+ res = pgfdw_get_result(conn, query);
+ if (res == NULL)
+ pgfdw_report_error(ERROR, NULL, conn, false, query);
+ last_res = res;
+
+ /*
+ * Verify that there are no more results
+ *
+ * We don't use a PG_TRY block here, so be careful not to throw error
+ * without releasing the PGresult.
+ */
+ res = pgfdw_get_result(conn, query);
+ if (res != NULL)
+ {
+ PQclear(last_res);
+ pgfdw_report_error(ERROR, res, conn, true, query);
+ }
But huge objection to that because this fragilizes the current logic
postgres_fdw is based on: PQexec returns the last result to caller,
I'd rather not break that logic for 9.6 stability's sake.
IIUC, I think each query submitted by PQexec in postgres_fdw.c contains
just a single command. Maybe I'm missing something, though.
A even better proof of that is the following, which just emulates what
your version of pgfdw_get_result is doing when consuming the results.
+ /* Verify that there are no more results */
+ res = pgfdw_get_result(fmstate->conn, fmstate->query);
+ if (res != NULL)
+ pgfdw_report_error(ERROR, res, fmstate->conn, true, fmstate->query);
This could even lead to incorrect errors in the future if multiple
queries are combined with those DMLs for a reason or another.
I'd like to leave such enhancements for future work...
Thanks for the comment!
Best regards,
Etsuro Fujita
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