What is php's behavior when connect to a db?

[zelzel.zsu@gmail.com]

What is php's behavior when connect to a db?

I've been told that php was once a dominant web programing language.
I've read a few chapters of a php book.

I was wonder what's php's performance.

Perl was once for a while a popular programming language for cgi.
But start very process per one web visit cause serioius problem to
system performance.

And then FASTCGI born.
I was impressed by its performance.

But recently i learn to do some php program which connect a mysql db.
It seems that the program run's very slow.

So, I have 2 questions:
1. does the os need to fork a php interpreter for every single web
request?
2. does the php connects to mysql all the time? that is does it need to
connect mysql
100 times when a user request the url 100 times?

If the answer if yes, i think that php's performance is unacceptable.


thanks.

[Erwin Moller]

Re: What is php's behavior when connect to a db?

zelzel.zsu@gmai l.com wrote:

Hi zeszel,
[color=blue]
> What is php's behavior when connect to a db?[/color]

depends on the database and the programmer.

[color=blue]
>
> I've been told that php was once a dominant web programing language.[/color]

once was?
It still IS.
:-)

[color=blue]
> I've read a few chapters of a php book.[/color]

good.
[color=blue]
>
> I was wonder what's php's performance.
>
> Perl was once for a while a popular programming language for cgi.[/color]

Yes, I did a lot of Perl too, but I am really happy I can do almost anything
in PHP nowadays.
At least I am able to read my own code.
;-)

[color=blue]
> But start very process per one web visit cause serioius problem to
> system performance.
>
> And then FASTCGI born.
> I was impressed by its performance.[/color]

Yes, that helped a lot.
I made Perl resident in memory, right?
And some precompiling-tricks too.
[color=blue]
>
> But recently i learn to do some php program which connect a mysql db.
> It seems that the program run's very slow.[/color]

Not good.
I expect PHP has little to do with that tough...
[color=blue]
>
> So, I have 2 questions:
> 1. does the os need to fork a php interpreter for every single web
> request?[/color]

How did you install PHP?
On which OS?
Did you install ISAPI under Windows?
etc.

Your question is a little hard to answer. :-)

In general: PHP is NOT slow, and can easily handle massive requests if the
underlying server is post-stoneage.
(Just my personal experience, based on PHP4/5 on RH8/FreeBSD/Windows2000
combined with IIS4/5/6 and Apache.)

[color=blue]
> 2. does the php connects to mysql all the time? that is does it need to
> connect mysql
> 100 times when a user request the url 100 times?
>
> If the answer if yes, i think that php's performance is unacceptable.
>[/color]

Well, why don't you read up bit at php.net?

*************** ***********
mysql_connect

(PHP 3, PHP 4, PHP 5)
mysql_connect -- Open a connection to a MySQL Server
Description
resource mysql_connect ( [string server [, string username [, string
password [, bool new_link [, int client_flags]]]]] )

Opens or reuses a connection to a MySQL server.

*************** ***********

In general: Do not worry about PHP's performance.
Worry about the databasequeries .

Most of the time people write bad repetive queries, and blame PHP.
I am not saying you do that, but I just see it a lot.
;-)


So if your site is very slow, try this:
- where does the script take up its time?
- isolate the part where the database is queried, and measure the time it
needs to complete your query.

You can use a crude microtime to measure roughly. It is enough to pinpoint
to the problemerea without complex debugging/profiling tools.

Works for me untill now in all cases.


Good luck.

Regrads,
Erwin Moller
[color=blue]
>
> thanks.[/color]