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From Paul Davis <paul.joseph.da...@gmail.com>
Subject Re: Some CouchDB internals questions?
Date Tue, 15 Mar 2011 19:32:00 GMT
On Tue, Mar 15, 2011 at 2:53 PM, Zdravko Gligic <zgligic@gmail.com> wrote:
>> Have you compacted your db and views?
>
> Yes
>
>> There's unfortunately no direct way to calculate a upper threshold, it
>> really depends on your method for inserting as well as how often you
>> compact.
>
> Once both (docs and view) are compacted, is the resulting size at all
> dependent on how the docs and/or views were created in the first place
> (one at a time or in bulk or whatever) ?
>

I think to get the absolute minimum post-compaction size you need to
compact twice. I haven't done lots of extensive testing on this, but
last I recall the basic logic was the first time can end up writing
docs in a somewhat randomish ordering depending on how they were
inserted.

>> This is due to the tail append storage which will orphan data
>> in the file as it writes new records to the various internal data
>> structures.
>
> My 1,500 docs are taking up almost 15 meg (roughly 1/4-1k docs with 2
> views + 1 view with doc re-emit) and I believe were around 50meg
> before compactions.
>

More importantly, what was the datasize post-compaction though? If
your main db is 15Meg, and you have a view that re-emits the doc, I'd
expect you to have a total size of at least 30Meg. Depending on what
you're emitting in the other two views getting closer to that 50 isn't
hugely out of the question.

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