Le lundi 21 mai 2012 16:08:27, Merlin Moncure a écrit : > On Mon, May 21, 2012 at 8:55 AM, Samba <saasira@xxxxxxxxx> wrote: > > If Stored Procedures are equivalent to prepared statements [ as far as > > preparing the query plan is concerned], then what i'm looking for is > > perhaps a Global Prepared Statements at the client/driver side. > > > > Specifically, It wold be good if the JDBC driver prepares all the queries > > for invoking stored procedures at once per JVM so that each connection > > need not incur the cost of preparing [parsing and storing] those queries > > per connection. > > > > Thus we can put all the queries [stored procedure calls] at a single > > place, and prepare those queries during boot of the server [or > > deployment of the web application], and then execute those queries > > endless times by closing just the resultset object while keeping the > > statement open for ever. > > > > I know this is not form to discuss the JDBC related questions but put my > > thoughts here to complete the question i raised. If folks think this idea > > is valid then i will take it up with the JDBC Driver team. > > Well, there is a client side component to statement preparation which > the JDBC driver also does. > > There is a reason why there are no global plans in postgres: it > complicates everything in the sense that there you have to deal with > shared memory, locking. and scope/lifetime issues. Even though it can > be a big reduction in memory consumption you're on the wrong side of > the tradeoff for most cases. If you want to leverage server side > objects with >1 client connections I strongly advise looking at a > connection pooler -- not the lame client side pooling solutions you > typically see with the java stack -- but something like pgbouncer. > This amortizes memory costs of server side plans. pgbouncer is > mostly compatible with JDBC; you have to disable automatic statement > preparation. and there is preprepare to help with prepared_statement and pgbouncer: https://github.com/dimitri/preprepare -- Cédric Villemain +33 (0)6 20 30 22 52 http://2ndQuadrant.fr/ PostgreSQL: Support 24x7 - Développement, Expertise et Formation
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