readdir() or use a table in a db?

StevenJ

Not sure if this should be in code critique or general, but since I am looking for "what is the best" - then that is why it's in code critique...........mods feel free to move.

I am (very slowly) in the process of putting together my own gallery for my photographs & producing my own online blog. (why bother you might ask - when there is so many open source stuff anyway? I ask myself that all the time....)

anyway.

The way it works, I upload photographs using an iframe. I can repeatedly upload photograph after photograph. It resizes them as necessary, and stores a thumb in one dir and the max sized image in another. Before any of the images are available in the gallery, I must go to a form to add a photo to the gallery, and from here, I can click on an input field, and this opens up a window with the following php code.

<?php

$dir_handle = @opendir(THUMB_DIR) or die("Unable to open $path");

echo "Directory Listing of THUMB_DIR <br/>";
	$count = 0 ;
	$jpgArray = array () ;
//running the while loop
while ($file = readdir($dir_handle)) 
{	
	if($file!="." && $file!="..")
	{ 
		if(strstr($file, '.jpg')) {

			$jpgArray[$count] = $file ;
			$count = $count + 1 ;
		}
	}
}

	rsort($jpgArray) ;
	foreach ($jpgArray as $key => $image) {
		?><img src="images/thumbs/<?php echo $image ; ?>" onclick="opener.Test('<?php echo $image ; ?>')" /><br />
<?php echo $image ; ?> <br /> <?php
		}
?>

from this, I simply click on the image I want to associate with the form I have completed, and it returns the filename to the input field, and, displays a thumbnail on the form page (showing the correct image will be associated with the contents of the form)

My question is, is this better than having a table of filenames for each image?

The gallery would probably only have a maximum of 1000 images.

When there are 1000 images in the dir, then obviously the readdir() would take time to run, but would this be excessive? or would adding the filenames to a MySQL table be preferable and faster?

regards

johnpeace

StevenJ;10897540 wrote:
My question is, is this better than having a table of filenames for each image?

The gallery would probably only have a maximum of 1000 images.

When there are 1000 images in the dir, then obviously the readdir() would take time to run, but would this be excessive? or would adding the filenames to a MySQL table be preferable and faster?

regards

Building systems that have already been built/perfected is a perfectly good way to learn things.

I'm pretty sure readdir() will always be faster than a database connection->query->result.

Likewise, reading from/writing to the filesystem is faster than reading from/writing to a DB.

laserlight

johnpeace wrote:
I'm pretty sure readdir() will always be faster than a database connection->query->result.

Likewise, reading from/writing to the filesystem is faster than reading from/writing to a DB.

The problem with such comparisons is that they do not necessarily consider the extra (useful) work that the database engine does. Unless an in-memory database is used, accessing a database amounts to accessing the filesystem, but with the extra power of the database thrown in.

Weedpacket

And it also misses the fact that the filesystem is itself a (highly specialised) database maintained by the operating system.

NogDog

Also, while it may be true that the connection to a database adds some overhead, realistically that overhead is probably a total non-issue unless you are talking about huge amounts of traffic, and even then it's probably not much of an issue unless accessing a remote database server. And then even if you can precisely quantify what that overhead is, the question still remains whether the advantages of using the database will out-weigh whatever that overhead is: if the use of an efficient data design and SQL can give you the output you need in 100 milliseconds plus 50 milliseconds of connection overhead, you're still ahead of the game if a readdir() into an array followed by some custom parsing and sorting PHP functions takes a total of 200 milliseconds, then who cares about that database connection overhead?

Or to make a long story short: performance issues are seldom simple or obvious, and the only way to be really sure is via the use of well-designed performance tests. And when you get down to things where the entire script runs in under a second regardless of which method you use, ease of maintenance and scalability may well be more important than saving a vew milliseconds here or there.

foyer

I would just keep it the way you have it, oh except I would change this:

if(strstr($file, '.jpg'))

$jpgArray[] = $file;

You don't need to keep track of the array keys it will do it for you 🙂