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Date: Sat, 7 Jul 2012 14:06:34 +0000 (UTC)
From: "Nick North (JIRA)" <jira@apache.org>
To: dev@couchdb.apache.org
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 =?utf-8?Q?d_document_ids_including_the_database_identity?=
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    [ https://issues.apache.org/jira/browse/COUCHDB-1373?page=3Dcom.atlassi=
an.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=3D13=
408678#comment-13408678 ]=20

Nick North commented on COUCHDB-1373:
-------------------------------------

Bumping this as there were no comments on my pull request https://github.co=
m/apache/couchdb/pull/28 which was intended to address it. If I'm going abo=
ut this the wrong way, then please do let me know so that I can improve my =
approach. Many thanks.
               =20
> Time-order=E2=80=8Bed document ids including the database identity
> ----------------------------------------------------------
>
>                 Key: COUCHDB-1373
>                 URL: https://issues.apache.org/jira/browse/COUCHDB-1373
>             Project: CouchDB
>          Issue Type: Improvement
>          Components: Database Core
>            Reporter: Nick North
>            Priority: Minor
>              Labels: uuid
>         Attachments: 0001-Add-etap-for-jira-1373.patch, 0002-utc_id_suffi=
x.patch, 0003-utc_id_suffix.patch, couch_uuids.patch, utc_machine_id.patch
>
>
> This suggestion is for an enhancement to the document id generation algor=
ithms in CouchDb. I am new to CouchDb, and this question addresses an old i=
ssue (https://issues.apache.org/jira/browse/COUCHDB-465) so please forgive =
me if I am retreading old ground.
> My application has a number of mutually replicating CouchDb instances and=
 I would like document ids to be monotonically-increasing per-instance, and=
 globally unique, and for the instance where the document was created to be=
 determinable from the id. (To be more accurate - I don't need to know anyt=
hing about the instance itself; just whether any two documents originated f=
rom the same instance.) The utc_random algorithm is not far from meeting th=
ese requirements, as ids are monotonic and almost certainly globally unique=
. However, the instance cannot be determined from the id, and there is a ti=
ny chance of an id clash between two instances. Both of these issues could =
be solved if the random part of the id could be replaced with a suffix that=
 is fixed in the ini file for each instance.
> To address this I have a modified version of couch_uuids.erl introducing =
a new utc_machine_id algorithm which reads a machine_id string from the ini=
 file and then generates ids using an internal utc_suffix method that just =
appends the string to the usual utc 14-byte string. utc_random then also us=
es the utc_suffix method, but its suffix is the usual random byte string.
> However, it is obviously a nuisance to have to maintain a non-standard di=
stribution, so I wondered if there is enough call for this sort of thing to=
 make it a part of the standard distribution? If there is, I'd be very happ=
y to make my code available for discussion/modification/inclusion. If there=
 are good reasons why this is a bad idea, then I'd also be very interested =
to hear them so that I can rethink my ideas. (It happens that the privacy a=
nd guessability concerns raised in the original discussion do not apply in =
my case.) If this question has been beaten to death, then I'm sorry for bot=
hering the group, and would be grateful if someone could point me to the di=
scussions so that I can understand the issues.

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