[PHP] PDO: How to fetch TIMESTAMP values?
I recently began evaluating the feasibility of reworking our current database access framework, which utilizes the PHP-native drivers for our database (Interbase), to one which makes use of the PDO extension. Unfortunately, I quickly hit a roadblock. I have tried every permutation available in the PDO documentation, as far as I can see, in order to retrieve the value of a TIMESTAMP-type field from a given table, but so far I have been unsuccessful. Using the PHP-native functions for Interbase, I used to be able to accomplish this with the following code: ?php $sql = SELECT TIMESTAMP_FIELD FROM MY_TABLE; $result = ibase_query($dbh, $sql); $row = ibase_fetch_row($result, IBASE_UNIXTIME); $field = $row[0]; echo $field; ? Here is one of the many [failed] methods I have attempted using a PDO: ?php $sql = SELECT TIMESTAMP_FIELD FROM MY_TABLE; $row = $dbh-query($sql); $field = $row['TIMESTAMP_FIELD']; echo $field; ? In the first instance, a numeric (integer) value would be displayed on the screen. In the PDO example, nothing is displayed. I have also tried rewriting the PDO code above as a prepared statement, but i get the same result. Has anyone else bumped up against problems with TIMESTAMP fields when using the Interbase PDO driver or some other? Any suggestions would be appreciated. Thanks! -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Persistent Database Connections
Thanks, Philip (and Richard also), for offering your impressions. Per Philip's suggestion, I ran ab (Apache Benchmark) to stress test the page that loads my persistent connection. Depending on the parameters I set for ab, I was able to increase the number of connections from my initial 9 to anywhere between 15 and 25. This number varied from one test to another - even if I left the ab parameters the same. I probably could have boosted the total connections even further by raising the number of connections/requests initiated by ab. So, while I still don't have a rock-solid way to predict just how many connections will be opened for a given number of users, at least I'm not stuck at 9 :-) I guess it took using an automated approach to simulating server load (e.g., ab) to force Apache to open additional connections to the database. Interestingly, I also observed during my testing that some connections opened by Apache were subsequently closed. So, this seems to answer my other question re. whether persistent connections stay open forever. I guess they don't. What seems clear is that Apache decides when to terminate active connections, not the database. Thanks again. Mike Philip Hallstrom [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] What I am baffled by is the fact that the total nunber of connections between the web server and my database seems to max out at 9. Why 9? Not that I have a problem with this number. I just want to understand how this limit was reached so that I might predict how the application will perform in a production capacity. I can't think of a reason it would max out at 9 other than perhaps you really don't have more than 9 connections open. My understanding is that Apache will open a connection per child, per database connection where a connection is made up of the host, user, and database. How many apache processes are running when you take this measurement? There's no gaurantee that each of them will have hit your web app and start up there own connection. You might use something like ab (apache benchmark) to hit a page that initiates a persistent connection to see what happens as the number of apache processes grows. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Persistent Database Connections
[Please note that even though I cite Interbase in my example, I believe my question can be generalized to all databases that allow persistent connections] I recently installed a trial version of Interbase on a development server that includes a nifty tool that allows me to monitor, among other things, the number of active connections to my server. After playing with this feature briefly, I noticed that SEVERAL connections are opened between my web server and the database. At first, I thought this was a little weird because I use the ibase_pconnect() function to establish communication with my database, and I expected to see only 1 connection. However, after doing some reading, I discovered that this behavior is probably by design - the result of Apache spawning several child processes, each one establishing its own persistent connection(s) to the database. What I am baffled by is the fact that the total nunber of connections between the web server and my database seems to max out at 9. Why 9? Not that I have a problem with this number. I just want to understand how this limit was reached so that I might predict how the application will perform in a production capacity. I have checked my Apache config (httpd.conf) file, and as far as I can tell, the maximum number of child processes is set to 20. So again I ask: why does the number of connections max out at 9? Shouldn't they max out at 20 or 21 (1 parent + 20 children)? And finally, I have noticed that the connections, once established, NEVER expire. I realize that this is sort of the point with persistent connections, but I was curious whether persistent connections are ever terminated or recycled. Any explanations/impressions would be appreciated. Mike FYI... My php.ini file is set to allow unlimited connections/unlimited persistent connections. Also, the trial license of the database I am testing claims to be limited to 1 client, and the only client accessing the database is my web app. Just thought I'd mention that as I don't think the number of connections has any direct correlation to the client license. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
