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https://issues.apache.org/jira/browse/COUCHDB-3314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15928227#comment-15928227
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Jan Lehnardt commented on COUCHDB-3314:
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This is cool stuff. My comment applies to both this and COUCHDB-3315.
1. the use-case we are trying to preserve here (create doc X on db A and db B
and not have a conflict when A and B replicate.) is _very_ rare. Deterministic
revisions are mostly relevant on later revs (especially on mobile/PouchDB sync).
2. I’m totally comfortable with billing 3.0 features as: we are trading
permanent deletes and cluster purge for the rare use-case of deterministic
initial revisions.
3. I’m less confident with adding a switch that will force users into trouble
past the point where they can do anything about it (e.g. you can’t purge
because you didn’t 0-…-create a year ago).
4. it’d be nice if we can keep an escape hatch open that would be in line with
existing semantics, I’m imagining a 2-ABC… _rev with new_edits=false, that
could create an initial doc rev with a deterministic revision. ([~rnewson]
tells me this is currently broken, but would be worth a fix in this context)
5. I don’t think we should introduce the 0- hack.
> Add an option in doc creation APIs to specify a random value for an initial
> doc revision
> ----------------------------------------------------------------------------------------
>
> Key: COUCHDB-3314
> URL: https://issues.apache.org/jira/browse/COUCHDB-3314
> Project: CouchDB
> Issue Type: New Feature
> Components: Database Core, HTTP Interface
> Reporter: Mayya Sharipova
>
> Currently the initial revision of a document is deterministic. For instance,
> anyone that has created an empty document probably recognizes the revision
> starting with "1-967a00dff...". In order to account for situations when a
> document is continually purged and recreated we're going to add randomness to
> this initial revision by specifying a 0-$rev in the request coordinator. We
> will then include this in the revision generation but drop the 0-$rev entry
> from the revision's path.
> Thus, the new API will look like this:
> acurl -X PUT
> https://http://adm:[email protected]:5984/test-db/newdoc1?rev=0-adfdafa123 -d
> '{}'
> And similarly for _bulk_docs
> For a user who wants to create a doc, then purge it, and then re-create, it
> is recommended to recreate it with another random revision.
> It is important to note that the 0-$rev only affects document creation. Once
> a document exists, updates to the document will continue to update their hash
> in the same deterministic fashion. Ie, once a document exists, identical
> updates will result in identical revisions.
> _________________
> The following changes need to be made in the code:
> 1. API changes to allow to specify random rev in doc PUT requests, _bulk_docs
> 2. Internals:
> 2.1 Use a new revision here:
> https://github.com/apache/couchdb-couch/blob/master/src/couch_db.erl#L886
> 2.2 Don't include provided 0-$rev entry to the revision's path (find wherever
> new_revid is called from; could be 2-3 places)
> 2.3 Reject a 0-$rev during replication
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