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From Mark Hahn <>
Subject Re: following fast doc updates
Date Tue, 25 Sep 2012 21:41:12 GMT
> Alternatively, you could use two dbs.

I came up with two are three schemes that require twice the number of
writes.  It bothers me to double the number of writes, although maybe it

Right now I'm implementing a scheme where a hash is saved in ram for every
doc id and "change type" with the version number of that change.  A "change
type" table is also kept in the doc with the version number that the
changed happened in.  By comparing the two version numbers I can detect
each unique change, even when multiple have occured.

Boy this is a pain.  If somone can come up with a simpler scheme to catch
each unique change it would be appeciated.

On Tue, Sep 25, 2012 at 12:02 PM, Paul Davis <>wrote:

> Alternatively, you could use two dbs. One db you could write "change
> requests" to (each request as a new doc) and then listen for changes
> on that and apply them in that logic. This also has that added benefit
> that you could do the timestamped dbname pattern for your changes feed
> dbs to (possibly depending on use case) remove some of the cruft
> buildup.
> On Tue, Sep 25, 2012 at 1:31 PM, Mark Hahn <> wrote:
> >> The _changes feed only ever shows leaf revisions
> >
> > AARRGGHH.  I am so screwed.  I have been working on a scheme that relies
> on
> > tracking every change.  And as everyone knows there is normally no way to
> > find out what changed in a doc.  I am going to have to add a history of
> > changes to each doc which it not only wasteful, but a pain to implement.
> >
> > Thanks for taking the trouble to give me bad news.
> >
> >
> > On Tue, Sep 25, 2012 at 10:19 AM, Adam Kocoloski <
> >wrote:
> >
> >> On Sep 24, 2012, at 5:16 PM, Mark Hahn <> wrote:
> >>
> >> > If I update a particular doc multiple times rapidly, is each update
> >> > guaranteed to show up in a continuous changes feed?  I am worried that
> >> the
> >> > change feed will be optimized to just show the latest value of a doc
> with
> >> > multiple updates.  This would break my logic.
> >>
> >> Your worries are justified.  The _changes feed only ever shows leaf
> >> revisions (i.e., latest updates to branches of the edit tree).  Regards,
> >>
> >> Adam

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