couchdb conflict resolution
Hello, I am very interested in understanding how conflict resolution works in couchdb: Is there a technical overview, somewhere, of how a node decides which revision wins? After a conflict is resolved, are old revisions discarded? Any technical details, short of slogging through the code, would be very welcome. Thanks, Aaron
Re: couchdb conflict resolution
Here is some high level text on it. https://issues.apache.org/jira/browse/COUCHDB-988 On Feb 15, 2011, at 10:14 AM, Aaron Boxer boxe...@gmail.com wrote: Hello, I am very interested in understanding how conflict resolution works in couchdb: Is there a technical overview, somewhere, of how a node decides which revision wins? After a conflict is resolved, are old revisions discarded? Any technical details, short of slogging through the code, would be very welcome. Thanks, Aaron
Re: couchdb conflict resolution
On Tue, Feb 15, 2011 at 5:14 PM, Aaron Boxer boxe...@gmail.com wrote: I am very interested in understanding how conflict resolution works in couchdb: Is there a technical overview, somewhere, of how a node decides which revision wins? After a conflict is resolved, are old revisions discarded? Any technical details, short of slogging through the code, would be very welcome. I'm not sure if this is the right level of detail for your purposes, but I found http://guide.couchdb.org/draft/conflicts.html very interesting. -- Stefan
Re: couchdb conflict resolution
Thanks, Stefan! I did see this already. Good for a high level view; but I am looking for the gory details. Cheers, Aaron On Tue, Feb 15, 2011 at 2:18 PM, Stefan Kögl koeglste...@gmail.com wrote: On Tue, Feb 15, 2011 at 5:14 PM, Aaron Boxer boxe...@gmail.com wrote: I am very interested in understanding how conflict resolution works in couchdb: Is there a technical overview, somewhere, of how a node decides which revision wins? After a conflict is resolved, are old revisions discarded? Any technical details, short of slogging through the code, would be very welcome. I'm not sure if this is the right level of detail for your purposes, but I found http://guide.couchdb.org/draft/conflicts.html very interesting. -- Stefan
Re: couchdb conflict resolution
Thanks, Paul! This is exactly the level of detail and granularity I am looking for. GIT is mentioned a few times in this issue write-up. So, does couch now use a modified form of GIT revision tracking? On Tue, Feb 15, 2011 at 12:11 PM, Paul J. Davis paul.joseph.da...@gmail.com wrote: Here is some high level text on it. https://issues.apache.org/jira/browse/COUCHDB-988 On Feb 15, 2011, at 10:14 AM, Aaron Boxer boxe...@gmail.com wrote: Hello, I am very interested in understanding how conflict resolution works in couchdb: Is there a technical overview, somewhere, of how a node decides which revision wins? After a conflict is resolved, are old revisions discarded? Any technical details, short of slogging through the code, would be very welcome. Thanks, Aaron
Re: couchdb conflict resolution
On Tue, Feb 15, 2011 at 3:11 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks, Paul! This is exactly the level of detail and granularity I am looking for. GIT is mentioned a few times in this issue write-up. So, does couch now use a modified form of GIT revision tracking? Its similar in theory but you'd be a bit hard pressed to pick that out without an pretty good understanding of both. Its merely just a reference that they both use a form of inverted-merkle tree, but beyond that the similarities are generally thin.
Re: couchdb conflict resolution
Thanks. So, if I learn me some Erlang and read couch_key_tree.erl, I will understand how merging is done? Also, where is the code for generating a version id? appreciate the help, Aaron On Tue, Feb 15, 2011 at 3:33 PM, Paul Davis paul.joseph.da...@gmail.com wrote: On Tue, Feb 15, 2011 at 3:11 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks, Paul! This is exactly the level of detail and granularity I am looking for. GIT is mentioned a few times in this issue write-up. So, does couch now use a modified form of GIT revision tracking? Its similar in theory but you'd be a bit hard pressed to pick that out without an pretty good understanding of both. Its merely just a reference that they both use a form of inverted-merkle tree, but beyond that the similarities are generally thin.
Re: couchdb conflict resolution
On Tue, Feb 15, 2011 at 3:45 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks. So, if I learn me some Erlang and read couch_key_tree.erl, I will understand how merging is done? There is no merging. Conflicts are resolved by deleting one of the conflicted revisions. This being a major departure from the Git model. Also, where is the code for generating a version id? couch_db:new_revid/1 appreciate the help, Aaron On Tue, Feb 15, 2011 at 3:33 PM, Paul Davis paul.joseph.da...@gmail.com wrote: On Tue, Feb 15, 2011 at 3:11 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks, Paul! This is exactly the level of detail and granularity I am looking for. GIT is mentioned a few times in this issue write-up. So, does couch now use a modified form of GIT revision tracking? Its similar in theory but you'd be a bit hard pressed to pick that out without an pretty good understanding of both. Its merely just a reference that they both use a form of inverted-merkle tree, but beyond that the similarities are generally thin.
Re: couchdb conflict resolution
ahhh, ok. So key tree is used to detect conflict, and to reference different conflicted versions. Got it, thanks. On Tue, Feb 15, 2011 at 3:50 PM, Paul Davis paul.joseph.da...@gmail.com wrote: On Tue, Feb 15, 2011 at 3:45 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks. So, if I learn me some Erlang and read couch_key_tree.erl, I will understand how merging is done? There is no merging. Conflicts are resolved by deleting one of the conflicted revisions. This being a major departure from the Git model. Also, where is the code for generating a version id? couch_db:new_revid/1 appreciate the help, Aaron On Tue, Feb 15, 2011 at 3:33 PM, Paul Davis paul.joseph.da...@gmail.com wrote: On Tue, Feb 15, 2011 at 3:11 PM, Aaron Boxer boxe...@gmail.com wrote: Thanks, Paul! This is exactly the level of detail and granularity I am looking for. GIT is mentioned a few times in this issue write-up. So, does couch now use a modified form of GIT revision tracking? Its similar in theory but you'd be a bit hard pressed to pick that out without an pretty good understanding of both. Its merely just a reference that they both use a form of inverted-merkle tree, but beyond that the similarities are generally thin.
