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Date: Tue, 23 Apr 2013 10:28:45 +0200
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 <CAL+Y1ntbRoKqNveDtwH21nPH+LTVG+WdwZscSNsak+=wWG+NuA@mail.gmail.com>
Subject: Re: Problem with restart of continuous replication
From: Dave Cottlehuber <dch@jsonified.com>
To: user@couchdb.apache.org
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On 23 April 2013 09:01, Calle Arnesten <calle.arnesten@codekick.com> wrote:
> Hi,
>
> I have a two-way continuous replication set up between two servers with C=
ouchDB. About a week ago we had a DNS problem that caused the machines to n=
ot to be able to communicate for almost 2 hours. My assumption was that Cou=
chDB would automatically try to restart the replication. When I double-chec=
ked this a day or two later, replication was only restarted for one way and=
 not both. After rebooting the machine the replication started working both=
 ways again.
>
> Now my question is: Was my assumption wrong that replication should be re=
started automatically? If not, what could be the cause of it not working? T=
he machine that it happened to have CouchDB 1.2.1 installed.

replication will retry a certain number of times and then give up if
the connection does not work, 10 by default.

See http://wiki.apache.org/couchdb/Replication#New_features_introduced_in_C=
ouchDB_1.2.0
for the details.

> Also, do you have any recommendations on how to monitor that replication =
works and notify by mail when it doesn't?

I'd suggest one of 2 things, not having used either personally -


use the replicator DB mentioned in the above link, and monitor the
state of that named document:

GET /_replicator/my_replication_task

You'll get something back like this:

{
   "_id": "my_replication_task",
   "_rev": "2-539eca65da0cfbd416fb335dcc5129c2",
   "source": "http://somewhere.iriscouch.com/mydb/",
   "target": "mydb",
   "create_target": true,
   "continuous": true,
   "owner": "admin",
   "_replication_state": "error",
   "_replication_state_time": "2013-04-22T18:31:44+02:00",
   "_replication_id": "f1bdf920b49bb9156b2c3147f30d18c3"
}

Which seems self-explanatory.

The other option is to GET /_active_tasks

[
    {
        "checkpointed_source_seq": 307493,
        "continuous": true,
        "doc_id": "my_replication_task",
        "doc_write_failures": 0,
        "docs_read": 0,
        "docs_written": 0,
        "missing_revisions_found": 0,
        "pid": "<0.300.0>",
        "progress": 70,
        "replication_id": "1d1f73e98957aa03e3fa9291e05ed7e0+continuous",
        "revisions_checked": 3962,
        "source": http://somewhere.iriscouch.com/mydb/",
        "source_seq": 461843,
        "started_on": 1366705545,
        "target": "mydb",
        "type": "replication",
        "updated_on": 1366705552
    }
]

Which for a continuous replication should always be present.

A+
Dave