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#1 (**permalink**) 02-28-2008, 07:37 AM

I am using RAND() in rapid sequence, possibly on different connections.
I expected to get different numbers from RAND(). I didn't. I get the same
number within a given timeframe - it's like it's driven entirely by
microtime.
Am I stuck?

I need different numbers for images. The only solution I can think of is to
get 'the next image' from the database. to make it look random. but that's
not very random.

any ideas?

#2 (**permalink**) 02-28-2008, 07:37 AM

On Sat, 22 Apr 2006 18:47:49 -0700, Jim Michaels wrote:
> I am using RAND() in rapid sequence, possibly on different
> connections. I expected to get different numbers from RAND(). I
> didn't. I get the same number within a given timeframe - it's like
> it's driven entirely by microtime. Am I stuck?
>
> I need different numbers for images. The only solution I can think of
> is to get 'the next image' from the database. to make it look random.
> but that's not very random.
>
> any ideas?

Generate your random number on the application level? Use an
autoincrement column instead of a random one? Start with telling us what
problem you're trying to solve rather than telling us your not-working
solution. That is, "I want to have a unique file name I can give to an
image associated with information stored in a table" instead of "RAND()
isn't random enough, so I can't make a file name out of it and guarantee
uniqueness".

--
100. Finally, to keep my subjects permanently locked in a mindless trance, I
will provide each of them with free unlimited Internet access.
--Peter Anspach's list of things to do as an Evil Overlord

#3 (**permalink**) 02-28-2008, 07:37 AM

"Peter H. Coffin" <hellsop@ninehells.com> wrote in message
news:slrne4m0fr.mnd.hellsop@othin.ninehells.com...
> On Sat, 22 Apr 2006 18:47:49 -0700, Jim Michaels wrote:
>> I am using RAND() in rapid sequence, possibly on different
>> connections. I expected to get different numbers from RAND(). I
>> didn't. I get the same number within a given timeframe - it's like
>> it's driven entirely by microtime. Am I stuck?
>>
>> I need different numbers for images. The only solution I can think of
>> is to get 'the next image' from the database. to make it look random.
>> but that's not very random.
>>
>> any ideas?
>
> Generate your random number on the application level? Use an

tried that. same problem. no solution yet. microsecond resolution of
uniqid() isn't fast enough to give me random images. this must be cached in
memory at the server or something.

> autoincrement column instead of a random one? Start with telling us what
> problem you're trying to solve rather than telling us your not-working

Trying to generate multiple random images by a onsie-script that selects one
hopefully unique image (from an existing table of images that has id
numbers) on a web page. At the very least, they should be different images
from each other, so they *could* be sequential if I can't get random to
work.

> solution. That is, "I want to have a unique file name I can give to an
> image associated with information stored in a table" instead of "RAND()
> isn't random enough, so I can't make a file name out of it and guarantee
> uniqueness".
>

#4 (**permalink**) 02-28-2008, 07:38 AM

"Jim Michaels" <NOSPAMFORjmichae3@yahoo.com> wrote in message
news:fKKdnXFcNOVJsNHZnZ2dnUVZ_uWdnZ2d@comcast.com. ..
>
> "Peter H. Coffin" <hellsop@ninehells.com> wrote in message
> news:slrne4m0fr.mnd.hellsop@othin.ninehells.com...
>> On Sat, 22 Apr 2006 18:47:49 -0700, Jim Michaels wrote:
>>> I am using RAND() in rapid sequence, possibly on different
>>> connections. I expected to get different numbers from RAND(). I
>>> didn't. I get the same number within a given timeframe - it's like
>>> it's driven entirely by microtime. Am I stuck?
>>>
>>> I need different numbers for images. The only solution I can think of
>>> is to get 'the next image' from the database. to make it look random.
>>> but that's not very random.
>>>
>>> any ideas?
>>
>> Generate your random number on the application level? Use an
>
> tried that. same problem. no solution yet. microsecond resolution of
> uniqid() isn't fast enough to give me random images. this must be cached
> in memory at the server or something.
>
>> autoincrement column instead of a random one? Start with telling us what
>> problem you're trying to solve rather than telling us your not-working
>
> Trying to generate multiple random images by a onsie-script that selects
> one hopefully unique image (from an existing table of images that has id
> numbers) on a web page. At the very least, they should be different
> images from each other, so they *could* be sequential if I can't get
> random to work.
>
>> solution. That is, "I want to have a unique file name I can give to an
>> image associated with information stored in a table" instead of "RAND()
>> isn't random enough, so I can't make a file name out of it and guarantee
>> uniqueness".
>>
>
>

found the solution. the browser was cacheing the image and therefore giving
me duplicates. the random number generator in the DB is fine. I don't have a
"microtime" problem with it. All my thinking was bogus. I've been wrong
before.

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RAND() generating same number in rapid sequence