On 4/5/2017 2:56 PM, David Storrs wrote:
On Wed, Apr 5, 2017 at 1:39 PM, Marc Kaufmann <[email protected]> wrote:
> Thanks David, that makes a little sense also because it often happens after
> there has been no activity on the server for a while. If it is a stale
> handle, is there something I can do about it?
Get a fresh handle instead of re-using an old one. I don't know what
this line does: (define dbc (study-db a-study)) but if it's
returning a cached handle then that's your problem.
Something like this would work:
(define (connect-me)
(postgresql-connect #:user "foo"
#:database "bar"
#:password "baz"
#:port 5432
))
(define dbc (connect-me))
(Note that this is illustrative, not necessarily efficient.)
Also, you might want to look into virtual connections and connection pools.
In addition to David's excellent suggestion:
Be aware that the server may close an idle connection, and you may get a
stale handle even from a pool. Depending on the DBMS you may need to
enable keep-alives and/or change idle connection timeouts on the server
so that a pool can keep connections open.
MySQL uses keep-alives by default, but there is a separate idle
connection timeout.
see
https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_wait_timeout
George
--
You received this message because you are subscribed to the Google Groups "Racket
Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
