Named / preparsed / preplaned(prepared) queries - Feature proposal

Hi all

I have an idea how to extend postgresql feature set.

I sugest named / preparsed / preplamned query mechanizm where named query is a simpliest form and preplaned query is the most sofisticated (implementation wise). Ie to have ability to assign a global and may be persistant NAME (or alias) for some query for some user. Similar how PREPARE related stuff does, but AFAIK, prepared statement are limited for the current user on current connection only.

with syntax like this:

NAMEDQUERY "select foo from bar where blah=$1" AS "myquery" [PREPARSED | PREPLANED REPLAN EVERY condition] [PERSISTENT] [FINAL] [FOR USER user1,user2]

And then modify user privileges to add privileges to create a NAMEDQUERY, to create it for others - typicaly useful for database administrator and the privilege of executing NAMED QUERY ONLY for some user - for example guest.

PERSISTANT tell the server that this named query should survive server restart.

FINAL: if Administrator set a named query as FINAL, no other user is able to override it.

PREPARSED: Rationale behind PREPARSED queries is that in most scenarios on web applications there is a simple not complicated select of data often in heap or memory or in the in memory index where actually fetching that data is faster then parsing a query string. So I thing a global cache of preparsed NAMEDQUERY statements is a good idea and on some loads can boost performance significantly.

PREPLANED: same as the preparsed, but the query plan is cached too. So in frequent simple queries (like common in ajax/comet applications where it ofen do some simple select to query a status of session etc), I thing it can remove significant burden (parsing and planning a query) from CPU .

yes, I know that a query plan that is superior now, could be inferior few minutes later. So I suggest a REPLAN EVERY condition, where condition can be whatever user like - time interval, changed N percent of tuples etc etc - Let user decide what mechanizm is best for him.

This feature can lead to two interested things. First, there is a decoupuling a database from application level and keep this two realm relatively separate, if underlying db structure is changed, just redefine named queries and do not touch application. It create some sort of easy to use abstraction layer. It is a bit "objectish" approach, because you can create a selfcontained database with data and method for its manipulation (if named query is set as PERSISTENT, should dump/restore and replication solutions do their job on persistant named queries as well)

Second thing is a powerful, simple, yet easy to use security feature with as much granularity as is possible. For example user guest, who have set a NAMED QUERY ONLY user privilege, will be limited only to queries that admin of the database defined for him, no matter what.I thing that it could be easy to use privilege sepration mechanizm.

I use postgresql in my projects since 6.x branch and I am happy with it, but proposed feature is on my Postgresql wishlist.
Any comments wellcome.

PS: Execuse my wrong english.