On Wed, Oct 01, 2003 at 09:01:23PM -0400, Neil Conway wrote: > On Wed, 2003-10-01 at 20:25, Jingren Zhou wrote: > > From the document, it seems that PREPARE/EXECUTE works only in the same > > session. I am wondering whether postgres can prepare a query (save the plan) > > for difference backends. > > The decision to store prepared statements per-backend, rather than in > shared memory, was made deliberately. In fact, an early version of the > PREPARE/EXECUTE patch (written by Karel Zak) stored prepared statements > in shared memory. But I decided to remove this, because:
> That's all the reasons I can think of off the top of my head for doing > things the way we do. However, I'm open to being convinced: if you think > we should store prepared statements in shm, feel free to make a case for > it. I think the current non-shared PREPARE/EXECUTE is right solution. The shared version require define new type of memory managment routines which is full compatible with the standard and abstract PostgreSQL mmgr tier. I worked on this because it was interesting experiment and now we know that write something like this is possible :-) I think final and right solution are persisten pre-forked backends which know to keep cached PREPARE/EXECUTE stuff (and a lot of others things) in own memory. It's nice and simple solution than use shared memory. Karel -- Karel Zak <[EMAIL PROTECTED]> http://home.zf.jcu.cz/~zakkr/ ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org