Crash when epgsql_sock:get_results/1 returns > 1 results after deferred constraint trigger raises exception about epgsql HOT 4 OPEN

On Fri, 26 Feb 2021, 21:36 Erlend Hamberg, ***@***.***> wrote: After some investigation, I think this is related to initially deferred constraint triggers. I was able to reproduce this with the following table + constraint trigger: create table my_table (x int); create or replace function my_check() returns trigger as $$ begin if new.x >= 10 then raise 'x must be < 10'; end if; return null; end; $$ language 'plpgsql'; create constraint trigger my_trigger after insert or update on my_table initially deferred for each row execute procedure my_check(); … and the following code: {ok, C} = epgsql:connect(#{ host => "localhost", username => "mydb", database => "mydb" }), {error, _} = epgsql:equery(C, "insert into my_table values(11)", []), ok = epgsql:close(C). Which crashes because epgsql_sock:get_results(Sock) returns more than one value: {case_clause, [{ok,1}, {error, {error,error,<<"P0001">>,raise_exception, <<"x must be < 10">>, [{file,<<"pl_exec.c">>}, {line,<<"3876">>}, {routine,<<"exec_stmt_raise">>}, {severity,<<"ERROR">>}, {where, <<"PL/pgSQL function my_check() line 4 at RAISE">>}]}}]}} However, if I change from equery to squery, it works as expected: […] {error, _} = epgsql:squery(C, "insert into my_table values(11)"), % matches […] Also, if the constraint trigger is *not* initially deferred, things work with equery again: drop trigger my_trigger on my_table; create constraint trigger my_trigger after insert or update on my_table --initially deferred for each row execute procedure my_check(); I guess what's happening is that the {ok,1} comes from the insert which initially succeeds – until the deferred constraint trigger is invoked and raises the exception, which returns an error value. That would explain why two results are returned. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#256 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADHA7RWTOLUPIRA45OX6ZDTBAA6XANCNFSM4YIVKESA> .