Re: Image library

That was my original idea - and to take things to extremes, you might even want to recurse directories: using only a couple of recursiveness levels (1-1000/1-1000/1-1000.jpg) would ensure 1 bil. files without getting more than 1000 in any singe directory. The really nice thing about this approach is that you can start with a single level and in the unlikely event you get more than 1 mil. (you wish! :)) then you can add another in no time, with a down time of probably ten minutes. In a slightly different train of thoughts, since this approach is so flexible, I'd recommend going for 500 files per directory - that's a limit which guarantees no slowdown. (And yes, I've read Jay's argument, but I have heard so many counter-arguments throughout time that I personally prefer to stay on the safe side - it's no big deal after all). Just my 2c, obviously. Bogdan Justin French wrote:

So hash them into groups of 1000 images???? 1-1000 1001 - 2000 2001 - 3000 etc etc, and just name the files 1.gif, 2.jpeg, etc etc Justin French on 22/08/02 12:41 AM, Scott Houseman (ScottH@JamWarehouse.com) wrote:

Hi there. So what you are suggesting is using an AUTO_INCREMENT field, possibly the image's Primary Key as an identifier for that image file., which is fine by me, but surely one should store files across directories, as 10000 images in a single directory might slow down access to those images in the filesystem, or not so? Thanks for your input. Regards -Scott

-----Original Message----- From: DL Neil [mailto:PHPml@DandE.HomeChoice.co.uk] Sent: 21 August 2002 04:31 To: php-general@lists.php.net; Bogdan Stancescu Subject: Re: [PHP] Image library Scott (confirming Bogdan), Libraries of all types have had this concern for years - even though books are uniquely identified by ISBN, that is still not good enough for library purposes (eg multiple copies of a single title). So they, exactly as Bogdan suggests, use an "Accession" number sequence - which can be implemented very neatly in MySQL (from PHP) as an AUTO_INCREMENT field. Regards, =dn

I've seen this kind of random approach several times and I keep wondering why not counting the files instead. Yes, it may take a little longer when uploading but I personally think the safety of the approach is worth the insignificant speed sacrifice. Bogdan Scott Houseman wrote:

Hi all. This confirms what I suspected. The hash algrithm: I have a directory structure: dirs 0 - f, and within each of

these, the same

dir structure 0 - f. When an image gets uploaded into the library, do an md5sum of

the file, take

the first 2 chars of that hash and there's your path. e.g $PICDBPATH.'/a/7/a7b8be10b0e69fe3decaa538f1febe84' I'm not sure what the mathematical randomness of this is, but I'm sure

it's

pretty random, and the chances of collision should be virtually null, the only time you should

overwrite a

file is if you upload the exact same file(?) Is there a better way of doing this? Cheers -Scott

-----Original Message----- From: Justin French [mailto:justin@indent.com.au] Sent: 21 August 2002 03:25 To: ScottH@jamwarehouse.com; PHP General Subject: Re: [PHP] Image library on 21/08/02 9:45 PM, Scott Houseman (ScottH@JamWarehouse.com) wrote:

Which way would be the most efficient/fastest to access images

from an image

library. A) Store image files in a hash directory structure AND storing

each file's

information in a mysql table OR B) Storing image information in mysql table AND storing the

image in a BLOB

field in that table.

From all accounts I've read on this list, a database is not

usually faster than a filesystem. And for large amounts of files, like 1000's, a hash will speed it up more.

The way I see it, considerations to be taken into acount: - Is it quicker/better to retrieve image from table & then stream out

to

browser OR simply direct the browser to the file? i.e <IMG SRC="/imagelib/image.php?iImageID=10"> OR <IMG SRC="/imagelib/5/f/10"> - Will a database OR filesystem be more scalable i.e. which

wil perform

better when there are 10000 images in the libary?

Filesystem should be quicker. You need to think about how

you hash the

files up for the most even spread of files in each directory I guess. Justin

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