Re: DBD::PgSQL: More Queestions

[David Wheeler]

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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