Re: [PATCH] postgres_fdw connection caching - cause remote sessions linger till the local session exit

On Wed, Jul 1, 2020 at 5:15 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> If I understand it correctly, your suggestion is to add
> keep_connection option and use that while defining the server object.
> IMO having keep_connection option at the server object level may not
> serve the purpose being discussed here.
> For instance, let's say I create a foreign server in session 1 with
> keep_connection on, and I want to use that
> server object in session 2 with keep_connection off and session 3 with
> keep_connection on and so on.
> One way we can change the server's keep_connection option is to alter
> the server object, but that's not a good choice,
> as we have to alter it at the system level.
>
> Overall, though we define the server object in a single session, it
> will be used in multiple sessions, having an
> option at the per-server level would not be a good idea.

You present this here as if it should be a Boolean (on or off) but I
don't see why that should be the case. You can imagine trying to close
connections if they have been idle for a certain length of time, or if
there are more than a certain number of them, rather than (or in
addition to) always/never. Which one is best, and why?

I tend to think this is better as an FDW property rather than a core
facility, but I'm not 100% sure of that and I think it likely depends
somewhat on the answers we choose to the questions in the preceding
paragraph.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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