Question regarding DEALLOCATE pdo_stmt_00000001

Hello all,

I've been seeing lots of this processes in my database DEALLOCATE
pdo_stmt_00000001 with idle state.

Executing *select * from pg_stat_activity where query like
'DEALLOCATE%';*I can see some of them are idle for +/- 30 minutes, and
there is one idle
for 4 days.

When I checked one of the pid by executing *select * from pg_stat_activity
where pid = 63882;* (for example), after few minutes (can be longer), it
became *DISCARD ALL* and after that it was removed from pg_stat_activity.

I was wondering if this is the normal behavior, since some of them are idle
for +/- 30 minutes.

I am using PostgreSQL 9.3.2 and PgBouncer.

Any help is appreciated.

Regards,

-Laurentius