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From Jonathan Williamson <...@netcopy.co.uk>
Subject Re: Why are reads from CouchDB so slow? (1.5MB/s or thereabouts)
Date Fri, 23 Mar 2012 11:37:13 GMT
# ping 127.0.0.1
...100 pings...
100 packets transmitted, 100 received, 0% packet loss, time 99004ms
rtt min/avg/max/mdev = 0.021/0.028/0.144/0.013 ms

On Fri, Mar 23, 2012 at 11:21 AM, CGS <cgsmcmlxxv@gmail.com> wrote:
> ...also, it would be nice to know how you inserted the documents and if
> they have attachments (at that size, I suppose they have). Could you also
> provide a result from ping 127.0.0.1 for response time fluctuations?
>
> CGS
>
>
>
>
> On Fri, Mar 23, 2012 at 12:16 PM, Jason Smith <jhs@iriscouch.com> wrote:
>
>> Hi, Jonathan.
>>
>> Can we start by identifying how fast you think **is** reasonable. What
>> speeds were you expecting? And on what grounds do you base that
>> expectation?
>>
>> (For example, perhaps connecting and fetching one row from MySQL?)
>>
>> On Fri, Mar 23, 2012 at 11:06 AM, Jonathan Williamson <jon@netcopy.co.uk>
>> wrote:
>> > Hi everyone,
>> >
>> > I posted this question on Stack Overflow and Jason Smith suggested I
>> > try this group instead.
>> >
>> >> I have a CouchDB (1.1.1) server running that contains a lot of
>> documents in the 400-600KB size range.
>> >>
>> >> If I time fetching a full document from the database (not from a view,
>> just the raw document) it takes 200-400ms to complete which equates to
>> around 1.5MB/s throughput.
>> >>
>> >> If I write the same data to raw files on disk they load in 10-20ms
>> (around 25-50 MB/s).
>> >>
>> >> I'd expect CouchDB to have some overhead, but an order of magnitude
>> (and some) seems crazy for what is essentially a read!
>> >>
>> >> Can anyone shed some light onto why this might be the case?
>> >>
>> >> Update: As requested below, a timing from curl:
>> >>
>> >> # time curl http://localhost:5984/[dbname]/[documentname]
>> >>
>> >> real    0m0.684s
>> >> user    0m0.004s
>> >> sys     0m0.020s
>> >>
>> >> The fetched document was 642842 bytes. I've tested it on both a
>> standard 1TB harddisk and an EC2 instance (EBS volume) with similar results.
>> >
>> > There was some discussion about the post which can be found here:
>> >
>> http://stackoverflow.com/questions/9807200/why-are-reads-from-couchdb-so-slow-1-5mb-s-or-thereabouts
>> >
>> > Thanks,
>> >
>> > Jon.
>>
>>
>>
>> --
>> Iris Couch
>>



-- 
Jon

Jonathan Williamson
Systems Architect
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