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From Paul Davis <>
Subject Re: Some basic couchdb questions
Date Sat, 04 Apr 2009 15:20:47 GMT
On Sat, Apr 4, 2009 at 3:04 AM, howard chen <> wrote:
> Some quick questions:
> 1. How many DB can be created in a single couchdb server?

More than 500,000 have been created. Not sure what the current maximum
reported number is.

> 2. Are there any length limit on key & value of a document?

HTTP post bodies are limited in size by mochiweb to something like
4GiB which indirectly limits CouchDB document sizes. The amount of
available RAM is also a limit. A single member on the document should
not be limited in size. Map/Reduce key values are not limited in size.
Results returned from reduce functions should stay relatively small in
size. growing at less than approximately log(# keys reduced).

> 3. WIll there be max. number of documents?

Nothing enforced directly by couchdb. The only limit should be the
relative hardware limits.

> 4. I found that when inserting large ammount of rows into couchdb, it
> is quite slow (e.g. due to UTF-8 conversion, due to HTTP call...etc),
> are there any way to improve?

What versions of Erlang and CouchDB and how are you inserting data?

If you're not at least on 0.9 and one of the last two or three
releases of Erlang you should upgrade both. Also, make sure that
you're using bulk docs to load your databases on initial import. Also,
for extra bonus points, sort all of your documents before loading,
though this is least important.

Paul Davis

> Thanks.

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