[TYPO3-core] TYPO3 md5 hashes - exemplified in bug#4363

[Martin Kutschker]

Dmitry Dulepov schrieb:
> Hi!
> 
> Martin Kutschker wrote:
> 
>> This bug is more a DB/DBAL issue:
>> http://bugs.typo3.org/view.php?id=4363
>>
>> Buuut, why does TYPO3 has the habit to truncated md5 hashes? I mean, 
>> they have a certain length on purpose.
>>
>> What will break if we try and use the full length hash whenever 
>> possible? IMHO those extra bytes are well spent for any cache index.
> 
> Indexes may be not used by mysql. Mysql often decides not to use long 
> indexes.

Hm, this might be a problem with the other issue (see below).

But this has to be checked: where does TYPO3 build indices based in md5 
hashes and whole long does the key get. As the hash will be pretty much at 
start of the key it won't matter much.

Eg
hashcol,intcol,stringcol - if necessary the part of the stringcol of the 
index can be shortened quite easily.

So I don't think we'll run into an issue here.

> In my opinion truncated md5 is not valid thing. It is like truncating 
> password: the less symbols the more chances to get the same in another 
> entry.

That's what I meant with "they have a certain length on purpose" :-)

Masi