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From Robert Newson <robert.new...@gmail.com>
Subject Re: perfomance?
Date Wed, 24 Mar 2010 11:20:12 GMT
It's a code change to increase the chunk size, it's not currently a
configuration setting. When I was testing this I increased it to 64k
and 128k, it didn't make much difference (it's quite possible I didn't
do it correctly, though I did verify that I had larger chunks of
attachment data in the file).

B.

On Wed, Mar 24, 2010 at 11:13 AM, Vasili Batareykin <john2do@gmail.com> wrote:
>> I have measured the difference between serving static files from
>> apache2 vs. attachments from couchdb. It's always faster to do so via
>> apache2, and, on average, couchdb was 2-4 times slower at serving the
>> same data as apache2.
>>
>
> in my case nginx vs couchdb 10x slowdown. on static files.
>
>
>>
>> This doesn't surprise me. Attachments are interleaved in chunks so
>> that concurrent writers do not block each others progress (since only
>> one process can append to a file at a time). So reading a file from
>> couchdb involves seeking to those chunks (and they're small, 4k or
>> less) and then sending them. As Randall points out, apache2 can just
>> call sendfile().
>>
>
> couchdb eats CPU not io. on small (two attachments, 800kb file size on disk)
> db.
> i don't know about real work(#/sec) with 50k+ files and 20Gb size of pics
> (80Gb in db?)
>
> can i change size of this chunk? to 32,64kb or 128? yes i know about
> overhead on disk.
>

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