On Thu, Jun 16, 2011 at 05:19:41PM -0400, Tom Lane wrote: > Peter Bex <peter....@xs4all.nl> writes: > > But when I try to do the same but pas the 2 as a parameter, > > (I do "EXECUTE bar($1)" with $1 bound to "2"), I get an error: > > Why would you do that, rather than executing the prepared statement > directly with PQexecPrepared?
I'm writing a Scheme language binding and currently I simply don't have any bindings for this function, and a user of this library was experimenting with some optimizations for his code and ran into this. I was kind of hoping to avoid having too many special-purpose functions and since there's also an SQL "EXECUTE" function, PQexecPrepared seemed a bit redundant. > Interposing an EXECUTE doesn't do anything but add parsing overhead. Is this parsing overhead of an EXECUTE statement (which should be very short and simple) *that* significant compared to the savings you get when preparing a complex SQL statement which is executed many times? > The reason this particular case doesn't work is that utility statements > (including EXECUTE) don't have any support for $n parameters. Why not, is it simply something nobody ever needed? It seems rather logical to be able to replace any literal by an equivalent parameter in any SQL statement. I should probably add support for PQexecPrepared at some point but even then, as a user, I'd probably expect this to be possible for reasons of symmetry and regularity. It might also make it easier for certain types of generated SQL. Cheers, Peter -- http://sjamaan.ath.cx -- "The process of preparing programs for a digital computer is especially attractive, not only because it can be economically and scientifically rewarding, but also because it can be an aesthetic experience much like composing poetry or music." -- Donald Knuth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
