postgres@digoal:~ % pg_ctl promoteserver promotingpostgres@digoal:~ % psqlpsql (9.3.4)Type "help" for help.postgres=> create table test(id int primary key, info text, crt_time timestamp);CREATE TABLEpostgres=> create or replace function f(v_id int) returns void as $$postgres$> declarepostgres$> beginpostgres$>   update test set info=md5(now()::text),crt_time=now() where id=v_id;postgres$>   if not found thenpostgres$>     insert into test values (v_id, md5(now()::text), now());postgres$>   end if;postgres$>   exception when others thenpostgres$>     return;postgres$> end;postgres$> $$ language plpgsql strict;sCREATE FUNCTIONpostgres=> select f(1); f --- (1 row)postgres=> select * from test; id |               info               |          crt_time          ----+----------------------------------+----------------------------  1 | 9de5370fe00c7ed52b48080e2fb3efc9 | 2014-06-27 19:07:14.725201(1 row)postgres=> select f(1); f --- (1 row)postgres=> select * from test; id |               info               |          crt_time          ----+----------------------------------+----------------------------  1 | f91841b8d4a52cb4ce82e835aa161283 | 2014-06-27 19:07:20.969022(1 row)postgres@digoal:~ % cdpostgres@digoal:~ % vi test.sql\setrandom v_id 1 50000000select f(:v_id);postgres@digoal:~ % pgbench -M prepared -n -r -f ./test.sql -c 16 -j 4 -T 30transaction type: Custom queryscaling factor: 1query mode: preparednumber of clients: 16number of threads: 4duration: 30 snumber of transactions actually processed: 1512165tps = 50368.843235 (including connections establishing)tps = 50416.031069 (excluding connections establishing)statement latencies in milliseconds:        0.001875        \setrandom v_id 1 50000000        0.313934        select f(:v_id);