Re: Cache
| From: | Richard Lynch | Date: | Tue, 17 May 2005 01:29:33 +0000 |
| Subject: | Re: Cache | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-215351@lists.php.net to get a copy of this message | ||
On Mon, May 16, 2005 12:09 pm, Evert | Rooftop said:
> $id1 $id2 and $id3 are when they are combined unique
>
> * Is there a chance of collision when MD5 is used on the id's and the
> ids are long strings
Yes. I think it's like 1 in 2 billion odds.
If you can concatenate $id1$id2$id3 and get a guaranteed unique string,
why not just use that as your unique string?
There are, of course, several good reasons NOT do, which may or may not
apply to your case:
Exposing the id's would be a security flaw.
Concatenating all three id's isn't really unique, after all. (EG all
three are integer IDs from MySQL.)
The concatenation of all three is WAY too long.
> * Is serialize the fastest way to serialize ;) ?
Probably, but not serializing at all, and stuffing the data directly into
shared memory would perhaps be faster, at least as I vaguely understood
the results of a thread on serialization on this very forum from a month
or two ago. (Check archives for "serialize" "shared memory" and "Rasmus
Lerdorf" who weighed in with a succinct explanation of how to avoid
serialization if that performance hit was really a problem (unlikely as
that was))
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