On 31 March 2017 at 16:32, Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote:
> On 2017/03/31 8:28, David Rowley wrote: > >> create table t (a int, b int); >> insert into t1 select x/100,x/100 from generate_series(1,100000) x; >> create extension if not exists postgres_fdw; >> create server test_server foreign data wrapper postgres_fdw options >> (host 'localhost', port '5432', dbname 'postgres'); >> create foreign table ft_t (a int,b int) server test_server; >> select 'create user mapping for current_user server test_server >> options(user ''' || current_user || ''');'; >> \gexec >> select count(*) from pg_stat_Activity; -- > 6 >> analyze ft_t; >> ERROR: could not connect to server "test_server" >> DETAIL: FATAL: sorry, too many clients already >> CONTEXT: Remote SQL command: DECLARE c1 CURSOR FOR SELECT a, b FROM >> public.ft_t >> Remote SQL command: SELECT a, b FROM public.ft_t >> Remote SQL command: SELECT a, b FROM public.ft_t >> Remote SQL command: SELECT a, b FROM public.ft_t >> (lots of these) >> >> select count(*) from pg_stat_Activity; --> 105 >> >> I've not had a moment to check into what's going on. >> > > IIUC, I think the cause would be that since the foreign table ft_t is > considered to be still foreign on the foreign server, which is actually the > same server, postgres_fdw recursively repeats the loopback access to ft_t. > (So, the same thing would happen for something like: select * from ft_t.) > If the analysis is right, ISTM that it's the user's fault. > Oh of course... I see exactly what I did wrong :-( sorry for the noise. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
