#48764 [NEW]: PDO_pgsql::query always uses implicit prepared statements if v3 proto available

From:             mark dot kirkwood at catalyst dot net dot nz
Operating system: Linux 2.6.28 (Ubuntu) amd64
PHP version:      5.3CVS-2009-07-01 (snap)
PHP Bug Type:     PDO related
Bug description:  PDO_pgsql::query always uses implicit prepared statements if v3 proto available

Description:
------------
If the libpq v3 protocol is available, the PDO_pgsql::query will use
implicit prepared statements. This can be a big performance hit for apps
that execute a lot of small sql statements. It would be good to be able to
switch this feature off as required.

Example code snippet to illustrate the use case is below:

Looking at the php code, it seems that either of 

PDO::ATTR_EMULATE_PREPARES 
PGSQL_ATTR_DISABLE_NATIVE_PREPARED_STATEMENT

should be able to do this. However neither actually have any effect in
this case.

I have a patch that makes the latter work in this case.

Reproduce code:
---------------
//Example code snippet
// (now while this cries out to be converted to use $dbh->prepare and
// $stmt->execute(), more complex cases may not just reexecute
// the same or similar sql)
//
$dbh = new PDO($url, $user);
$dbh->beginTransaction();

for ($i = 0; $i < $num_execs; $i++) {
  $stmt = $dbh->query($sql);
}

//Adding these directives has no effect:
//
$dbh = new PDO($url, $user, "", array(PDO::ATTR_EMULATE_PREPARES =>
true));
//
//or
//
$dbh->setAttribute(PDO::PGSQL_ATTR_DISABLE_NATIVE_PREPARED_STATEMENT,
true);


Expected result:
----------------
Setting PGSQL_ATTR_DISABLE_NATIVE_PREPARED_STATEMENT or maybe
ATTR_EMULATE_PREPARES should stop server side prepare in PDO::query

Actual result:
--------------
Server side prepare is always used if libpq v3 protocol is detected.

-- 
Edit bug report at http://bugs.php.net/?id=48764&edit=1
-- 
Try a CVS snapshot (PHP 5.2):        http://bugs.php.net/fix.php?id=48764&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):        http://bugs.php.net/fix.php?id=48764&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):        http://bugs.php.net/fix.php?id=48764&r=trysnapshot60
Fixed in CVS:                        http://bugs.php.net/fix.php?id=48764&r=fixedcvs
Fixed in CVS and need be documented: http://bugs.php.net/fix.php?id=48764&r=needdocs
Fixed in release:                    http://bugs.php.net/fix.php?id=48764&r=alreadyfixed
Need backtrace:                      http://bugs.php.net/fix.php?id=48764&r=needtrace
Need Reproduce Script:               http://bugs.php.net/fix.php?id=48764&r=needscript
Try newer version:                   http://bugs.php.net/fix.php?id=48764&r=oldversion
Not developer issue:                 http://bugs.php.net/fix.php?id=48764&r=support
Expected behavior:                   http://bugs.php.net/fix.php?id=48764&r=notwrong
Not enough info:                     http://bugs.php.net/fix.php?id=48764&r=notenoughinfo
Submitted twice:                     http://bugs.php.net/fix.php?id=48764&r=submittedtwice
register_globals:                    http://bugs.php.net/fix.php?id=48764&r=globals
PHP 4 support discontinued:          http://bugs.php.net/fix.php?id=48764&r=php4
Daylight Savings:                    http://bugs.php.net/fix.php?id=48764&r=dst
IIS Stability:                       http://bugs.php.net/fix.php?id=48764&r=isapi
Install GNU Sed:                     http://bugs.php.net/fix.php?id=48764&r=gnused
Floating point limitations:          http://bugs.php.net/fix.php?id=48764&r=float
No Zend Extensions:                  http://bugs.php.net/fix.php?id=48764&r=nozend
MySQL Configuration Error:           http://bugs.php.net/fix.php?id=48764&r=mysqlcfg