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From Jason Smith <...@iriscouch.com>
Subject Re: Why are reads from CouchDB so slow? (1.5MB/s or thereabouts)
Date Fri, 23 Mar 2012 11:16:30 GMT
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

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