On 31-Aug-06, at 2:58 PM, Tom Lane wrote:
Peter Eisentraut <[EMAIL PROTECTED]> writes:
Gregory Stark wrote:
Driver interfaces expose very clearly to the user an explicit
interface to prepare and execute a query separately.
The JDBC documentation merely contains statements of the sort "A SQL
statement with or without IN parameters can be pre-compiled and
stored
in a PreparedStatement object. This object can then be used to
efficiently execute this statement multiple times." There is
absolutely no indication that the execution plan of the statement is
computed at the time of preparation.
The key word there is "efficiently". I think it is a reasonable
presumption on the user's part that a query done this way will have
less
overhead than just resubmitting the raw query each time.
The important thing I see here is that JDBC allows use of IN
parameters
with or without a PreparedStatement (no?).
No, not that I am aware of. You can create a statement, and execute
it, but you need a PreparedStatement to set IN parameters
So they've separated the
concepts of out-of-line parameters and "preparing" a statement.
That's
the distinction we have unfortunately fudged in the V3 protocol.
The protocol does let you use OOL parameters without retaining a
prepared plan, thanks to the hack introduced later to not plan the
unnamed statement at Parse time, but that's definitely a bit of a wart
on the original protocol design. Maybe it's good enough, or maybe
not.
regards, tom lane
---------------------------(end of
broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org
Dave
---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster
