On Wednesday, November 20, 2002, at 07:02 AM, Tim Bunce wrote:
> Ah, okay.
>
> The goal is always to reduce the work that execute() does as far
> as possible. I'd suggest that the preparse code generate a list of
> the 'fragments' of SQL between the placeholders. All execute has
> to do is effectively join the parts together.
Ooh, hey, that's not a bad idea.
> But it's probably not worth worrying about. The cost of the scan
> is tiny and would be dwarfed by other issues like how you handle
> memory allocation (like, measure all fragments and placeholder values
> first then allocate and merge, or concatenate each part into an SV).
Hrm, yes, good point. If I end up using PostgtreSQL 7.3's server-side
prepare, though, I'll likely to something similar to this, though, as
the execute syntax is (roughly):
EXECUTE prepared_statement_name('param1', 'param2', 'paramn')
So I would just have to append the escaped parameters in turn to
"EXECUTE prepared_statement_name(" plus a closing ")".
I need to think about how to create a prepared statement name, though.
Some sort of hash (like MD5) would be good, but that might incur too
much overhead. Ideas?
Regards,
David
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