[Pvfs2-developers] bstream bucket spreading

[Sam Lang]

Yes,  The bstream macro never used the coll_id.
-sam

On Jan 21, 2008, at 2:24 PM, Rob Ross wrote:

> New versions will still be able to find bstream files for files  
> created by old servers? -- Rob
>
> On Jan 18, 2008, at 12:42 PM, Pete Wyckoff wrote:
>
>> slang at mcs.anl.gov wrote on Fri, 18 Jan 2008 11:51 -0600:
>>> On Jan 17, 2008, at 3:26 PM, Pete Wyckoff wrote:
>>>
>>>> I just noticed this bit in trove-dbpf/dbpf.h.  The code carefully
>>>> builds ((<collid> << 24) | <handleid>) then does a modulo against
>>>> a power of 2, effectively stripping off all but the low bits of
>>>> the handleid.
>>>>
>>>> The collid is not used in the hash at all.  Just in case anybody
>>>> thought this was important.  I've ever only used one collection per
>>>> server.
>>>>
>>>
>>> KEYVAL_GET_BUCKET is left over from the days when we did a keyval  
>>> DB per
>>> file.  With just one keyval DB now, we don't use that macro --  
>>> there's no
>>> where in the code it gets called -- so you could safely remove it  
>>> if you
>>> want.
>>>
>>> As for BSTREAM_GET_BUCKET, that's funny that the coll-id isn't  
>>> used in the
>>> hash, but it turns out not to matter.  The buckets end up as  
>>> directories
>>> that allow us to keep the bstream directories smaller, but here  
>>> too, all
>>> those directories are within a directory for the entire  
>>> collection.  Go
>>> ahead and pull out the coll_id bits of the hash if you want.
>>
>> I killed the extranneous stuff.  Maybe it'll save somebody else some
>> head scratching in the future.
>>
>> 		-- Pete
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>