| From: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
|---|---|
| To: | Craig Ringer <craig(at)2ndquadrant(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Yury Zhuravlev <u(dot)zhuravlev(at)postgrespro(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Tatsuo Ishii <ishii(at)postgresql(dot)org> |
| Subject: | Re: NOT EXIST for PREPARE |
| Date: | 2016-03-23 16:16:28 |
| Message-ID: | CAHyXU0wsZ4_uosLOPHvOvx5KOFE+wOewmEw8SV4W4=wkecga2A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Mar 23, 2016 at 8:21 AM, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
> I'm not understanding the objection at all. You have N client
> sessions connecting to the database that all utilize the same named
> prepared statement. A typical pattern is for the application to
> prepare them all upon startup, but currently each PREPARE needs to be
> wrapped with an exception handler in case someone else prepared it
> first. Having an IF NOT EXISTS decoration simplifies this. This can
> happen both inside and outside of connection pooling scenarios.
I'm walking that back a bit -- this is only interesting in pooler
scenarios, especially pgbouncer where you have no way of knowing if
the statement is created or not. Of course, you can always re-prepare
them following a discard but that's quite pessimal in many cases.
Still, I've often wanted this exact feature.
merlin
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