the id version reflects an internal detail. The scheme for deriving replication ids changes over time but to prevent redo-from-start, we'll look for values generated with older versions of the scheme in the event of a miss (a missing _local checkpoint doc).
Is it necessary to CC Filipe's work email address? His apache.org address should receive this. B. On 20 June 2013 18:51, Robert Newson <[email protected]> wrote: > _replicate was always a blocking call, and then we added continuous > replication. Obviously it then makes no sense to wait for "the end". > > B. > > > On 20 June 2013 18:41, Jens Alfke <[email protected]> wrote: >> The wiki docs for _replicate don’t say so, but in practice the call appears >> to be synchronous unless the ‘continuous’ property is set. That is, it >> doesn’t return a response until the replication completes, and in fact the >> response JSON includes a bunch of statistics about the replication. >> >> I didn’t know this when I implemented TouchDB, so I made _replicate always >> asynchronous. (It made more sense to me, especially since my client code >> needed to be able to track the progress of a replication using >> _active_tasks, which meant it needed a response ASAP so it could get the >> task ID.) >> >> I’m amending this now for Couchbase Lite, but I’d like to make sure I know >> the semantics. Is it true that it’s always synchronous unless >> continuous=true, and then it’s asynchronous? >> >> Also, is there any description somewhere of what the properties in the >> synchronous response mean? Some are obvious, some less so. Here’s an example >> from 1.2: >> >> { >> "history": [ >> { >> "doc_write_failures": 0, >> "docs_read": 18, >> "docs_written": 18, >> "end_last_seq": 19, >> "end_time": "Thu, 20 Jun 2013 16:58:13 GMT", >> "missing_checked": 18, >> "missing_found": 18, >> "recorded_seq": 19, >> "session_id": "1cef7405d0e61fb0decc89323669a012", >> "start_last_seq": 0, >> "start_time": "Thu, 20 Jun 2013 16:58:13 GMT" >> } >> ], >> "ok": true, >> "replication_id_version": 2, >> "session_id": "1cef7405d0e61fb0decc89323669a012", >> "source_last_seq": 19 >> } >> >> I’m particularly curious (a) why “history” is an array, and (b) what >> “replication_id_version” means. >> >> —Jens
