Home » Database » DB » Bug #2865

[2004-12-01 11:17 UTC] andre dot steffens at adress-research dot de

Description:
------------
At the moment on each action (like query, etc.) a mysql_select_db() is done. This costs performance and it would be nice to do it only if it is required.

I think it could done with a private method like this:

function _select_db($db, $connection) {
static lastdb;
if ($lastdb != $this->_db) {
if (!@mysql_select_db($this->_db, $this->connection)) {
return $this->mysqlRaiseError(DB_ERROR_NODBSELECTED);
}
$lastdb=$this->_db;
}
}

[2004-12-03 16:42 UTC] andre dot steffens at adress-research dot de

my last solution doesn't work, try the following:

function selectdb($db = null)
{
static $lastdb;

if (!isset($db)) {
$db = $this->_db;
}

if ((($lastdb != $db && !$this->_new) || !$this->_db) && $db) {
unset($this->_db);
if (!@mysql_select_db($db, $this->connection)) {
switch (mysql_errno($conn)) {
case 1049:
return $this->raiseError(DB_ERROR_NOSUCHDB, null, null,
null, @mysql_error($conn));
case 1044:
return $this->raiseError(DB_ERROR_ACCESS_VIOLATION, null, null,
null, @mysql_error($conn));
default:
return $this->raiseError(DB_ERROR, null, null,
null, @mysql_error($conn));
}
}
}
$this->_db = $lastdb = $db;
if (!$this->_db) {
return $this->mysqlRaiseError(DB_ERROR_NODBSELECTED);
}

return DB_OK;
}

$this->_new is from my connect. I set it to true if a new connection is created (see #2814)

[2005-06-17 16:45 UTC] kevinrsours at yahoo dot com

There are two issues here.
1) Allowing new database connections when connect is called.
2) Removing the calls to mysql_db_select when they are unnecesary.

The first was addressed by 1905, but the second is still a problem. A bit of testing I did a while back showed that mysql_db_select, while harmless in terms of results, is more expensive then I expected. It would be nice to eliminate the calls to mysql_db_select if possible (at the very least if you always create new connections you don't need this)