Re: Bottlenecks with large number of relation segment files

(2013/08/05 20:38), Florian Weimer wrote:
> On 08/05/2013 10:42 AM, John R Pierce wrote:
>> On 8/5/2013 1:01 AM, KONDO Mitsumasa wrote:
>>> When we open file, ext3 or ext4 file system seems to sequential search
>>> inode for opening file in file directory.
>>
>> no, ext3/4 uses H-tree structures to search directories over 1 block
>> long quite efficiently.
>
> And the Linux dentry cache is rather aggressive, so most of the time, only the
> in-memory hash table will be consulted.  (The dentry cache only gets flushed on
> severe memory pressure.)
Are you really? When I put large number of files in same directory and open,
it is very very slow. But open directory is not.
So I think it's only directory search. Not file search in same directory. And I
heard before it.

Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center