On Wed, Mar 23, 2016 at 12:46 PM, Vladimir Sitnikov
<sitnikov.vladi...@gmail.com> wrote:
> 2016-03-23 16:21 GMT+03:00 Merlin Moncure <mmonc...@gmail.com>:
> Merlin> A typical pattern is for the application to
> Merlin> prepare them all upon startup, but currently each PREPARE needs to be
> Merlin> wrapped with an exception handler in case someone else prepared it
> Merlin> first.
> If you plan to have "prepare if not exists" at startup only, why don't
> you just wrap it with
> exception handler then?

That's impolite to our users.  Virtually all other commands have been
decorated with IF [NOT] exists to avoid having to guard with exception
handler -- why not this one?  Also, if the handler is on the client
side, it tends to be racey.

> If you plan to always issue "prepare if not exists", then you will
> have to send full query text
> for each prepare => overhead. Those repeated query texts are
> "endless copies of the same PREPARE statements" Craig is talking about.

No one is arguing that that you should send it any every time (at
least -- I hope not).

> Merlin>The client prepares the statement exactly
> Merlin>once.  The problem is there's no easy way to determine if someone else
> Merlin>prepared it first
> Merlin, if by "client" you somehow mean JDBC (e.g. pgjdbc), then it
> does track which connections
> have which queries prepared.

Again, not in pooling scenarios.  The problems integrating server side
prepared statements with pgbouncer are well known.


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