creating leaf sets node location incorrectly

[glenndavy]

when replicating between 2 boxen, passing a provider connection string that has more than just the dbname, fails to register correctly.

For eg on node2:

londiste3 someini.ini create-leaf node2 dbname=my_clone --provider "dbname=my_master host=db-master user=just_me"

creates a node_location entry on my_clone.pgq_node.node_location for node1 of "dbname=my_master".

Similarly (and I'm not sure at what point) node1 has a node2 entry for node_location of "dbname=my_clone".

In order to get things working, I just manually add a step and update the node_location column with correct db connection details.

I'm happy to drill in a bit and see if I can fix this (good chance to learn some python) and shoot you a pull request, however can you confirm my understanding of how this should work is correct?

[markokr]

Both of connect strings should have host= also in connect string. Giving connect string without it is usually a bug.
Not always - toy installations in single machine - but on real installaltions its a bug.

So perhaps Londiste should throw error in such cases?

[glenndavy]

Hi Markokr, sorry for my delayed response.
well the problem I'm having is not that it doesn't enforce passing in a 'host=' but that when I do pass in a host parameter, it is ignored and so I have to set it my self by updating node_location. So, if the error checking is based on the data written into pgq_node.node_location, not data passed in via --provider, then, yep that works from my pov.

[martinmarques]

This is an actual issue. Same experience here. Created the leaf with the --provider="dbname=mydb host=myhost" but no host added to the provider.
Maybe tomorrow I can try to get a patch.

[markokr]

I added error for that case. But then people complained who had testenv in single machine. So I downgraded it to warning:

self.log.warning('No host= in public connect string, bad idea')

Although it could probably be better worded.

[andrewsw-janrain]

seeing this bug too. It's not a matter of whether to warn or not on missing host= in public connection string, but that the public connection string is not faithfully inserted into the database at the time the leaf node is created.

given the following command line:

londiste3 test_slave.ini create-leaf node2 dbname=test --provider="dbname=test host=vm1 user=db_user password=secret"

I expect:

select node_location from pgq.node_location where node_name = 'node1'; 

to return:

dbname=test host=vm1 user=db_user password=secret

but instead it returns just:

dbname=test

and replication fails until I manually fix that up in the database.

edit: note that "node1" is the node name for the provider in the create-leaf call above.

[justizin]

I find it interesting that it's suggested in this thread that skytools should warn on missing host= in the public connection string, while in fact the example configurations all work only on a single machine, leaving all of the interesting not-the-same-machine situations to be resolved by the reader.

[markokr]

Following improvements are now done:

• warning on connect string without host=
• public_node_location= config param, so the connect string does not need to be given on command line.
• doc/howto/londiste3_simple_rep_howto.txt has host= param in command line examples.

What else should be improved so common user would not get confused?

What else is needed to close this bug?