+1
----- Original Message ----
From: Dossy Shiobara <[EMAIL PROTECTED]>
To: AOLSERVER@LISTSERV.AOL.COM
Sent: Wednesday, April 16, 2008 7:00:14 PM
Subject: Re: [AOLSERVER] ns_db and bind variable support
On 2008.04.17, Bas Scheffers <[EMAIL PROTECTED]> wrote:
> That brings me to another subject: do we want prepared statements?
Yes!
In web applications, one of the big performance hits is SQL query parse
time. The irony is, in web applications, the queries aren't really
dynamic: most can be parsed once, and different bind variable values
used at execution time.
In my local sandbox, where I've been hacking on bind variable support, I
also implemented an [ns_db prepare] which returns an opaque ID to an
entry in a prepared statement cache. The concept looks like this:
set stmt [ns_db prepare ?-pool $pool | -handle $handle? $sql]
set values [list a 1 b 2 ... z 26]
ns_db exec -statement $stmt $values
Or, something very much like that. One thought, to avoid having
application code store and save and retrieve the statement handle
between requests was to hash the SQL statement and make the opaque ID
the hash. The unlikely hash collision issue aside, this could fail
where a prepared statement can't be cached (and there's no way for nsdb
to "know" this)--so, caching/reuse of prepared statements really should
be left up to the application code, as the developer ought to know when
it can be reused vs. when it should be flushed/re-prepared.
--
Dossy Shiobara | [EMAIL PROTECTED] | http://dossy.org/
Panoptic Computer Network | http://panoptic.com/
"He realized the fastest way to change is to laugh at your own
folly -- then you can let go and quickly move on." (p. 70)
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