As part of some testing we were doing, we found that PHP's OCI8 extension had a bug in the way it used Oracle's statement caching. The fix is already in CVS and will be generally available in PHP 5.2.4. After a short period for you to send me comments, Antony Dovgal will also build a new PECL snapshot of OCI8.

He explains the issue, a problem attributed to the switching of a "hard pause" and "soft pause" when the script caching connects to the Oracle database server. This caching feature is enabled by adding an "oci8.statement_cache_size" value in your php.ini file (and has a default size of 20).

If you've been having issues with this request caching and want to get the fix right away, grab it from the CVS. Otherwise, keep an eye out for PHP 5.2.4 coming soon to correct the issue.

What Krishna pointed out was that specifying the client character set name as the optional fourth parameter to oci_pconnect() has a postive effect on performance. If you let the value default then PHP has to invoke code to determine what the client character set should be. This lookup may involve a potentially expensive environment check.

So, a speed increase might be as easy as adding another parameter to your scripts. Christopher includes an example to show where the value goes (in an oci_pconnect call).

Testing with the database and PHP both on my little old machine I was getting figures like 0.6 vs 2.7 seconds for 50,000 pconnect calls in the one script. I saw some other results that showed only a three-times difference.