[RESOLVED] Is it ok to do this while coding?

mband2000

Here is some code that I call from EACH page of my website.. and I was wondering is this slowing down my mysql database if I call this from each page like this?

<?
function Sql_Connection() {

$db = mysql_connect($sDBhost, "username", "password");
mysql_select_db("database", $db);
}

Sql_Connection();
?>

And whenever I run a query on my pages... it's like this

<?

mysql_query("SELECT * FROM table");

?>

Is this a bad way to connect to mysql? I ask because I notice my server becomes very slow when many users use my script.

rincewind456

There's nothing wrong with having a function for your connection, and there's nothing wrong with you select statement, providing you are using all the information that the query returns, if for instance your select all query returns 10 fields of date and you only use 5 then it is inefficient.

BTW do you close the connection after it has been used?

mband2000

are you talking about the function mysql_close()?

If so, I've never used it.... should I?

I never knew if it was somthing I needed.

by the way.. I have a high traffic website (15,000 users) so will mysql_close() help.. and should I place it after every query or just in the footer of the page?

rincewind456

mband2000 wrote:
are you talking about the function mysql_close()?

If so, I've never used it.... should I?

I never knew if it was somthing I needed.

by the way.. I have a high traffic website (15,000 users) so will mysql_close() help.. and should I place it after every query or just in the footer of the page?

Yes.
Yes.
It is.
It should do as it will specifically close a connenction rather than waiting for mysql to clean up and it only needs to be used at the end of the script.

mband2000

Thank you very much for your help... :-)

MarkBad311

I have a related question. About the mysql_close() do I close it after the results have been echoed back or as soon as I am done building the query? should I then exit the script after that? whats the proper syntax?

rincewind456

MarkBad311 wrote:
I have a related question. About the mysql_close() do I close it after the results have been echoed back or as soon as I am done building the query? should I then exit the script after that? whats the proper syntax?

You can call it as soon as you have finished querying the DB, but it's usual to close at the end of the php script, the difference in time is going to be negligable.

Syntax here.

Plasma

Im pretty sure PHP closes any open connections at the end of your page.

Also, in regards to your queyr:

SELECT * FROM table;

Thats asking mysql to return back ALL columns of ALL rows.

If there are 1000 rows in your database, mysql is sending 1000 rows worth of data back to the page each time its loaded.

If you only require a specific number of rows, or only access specific fields, you should alter your query:

SELECT id, name FROM table LIMIT 5

For example.

Roger_Ramjet

Never used mysql_close() and never likely to because:

"Freeing resources

Due to the reference-counting system introduced with PHP 4's Zend Engine, it is automatically detected when a resource is no longer referred to (just like Java). When this is the case, all resources that were in use for this resource are made free by the garbage collector. For this reason, it is rarely ever necessary to free the memory manually by using some free_result function. "

If your server does begin to suffer under the load you may want to benchmark connections against persistent connections mysql_pconnect() - but persistent connections have their own special problems.