I want split my database to multiple(sharding), What the best practice to alter my type of :db.type/ref attributes to type :db.type/long? According the [doc](http://docs.datomic.com/schema.html#Schema-Alteration), I must install a new attributes. eg. I have User & Account entity, now, I put the User and Account to difference db, the attribute :user/accounts can not still be type of :db.type/ref

Has anyone experienced difficulty getting a transactor running on AWS w/dyanmo db with version 0.9.5561.50 ?

@mgrbyte We had no issues with our transactor, we had issues with our peer, but it was a library conflict issue

what error are you seeing?

can a transaction function return txs as list-of-maps in addition to list-of-lists?

Yes

Transaction functions have macro-like evaluation

Transactor will keep expanding results until it reaches a fixed point

awesome.

did I mishear, or did someone say you should index all attributes by default?

The only cost is space and indexing time (when the transactor compacts the index), and you can always remove them later

so, that seems reasonable

@favila you can also add an index later on an attribute, right?

yes

Say, is there anything like a $DATOMIC/bin/transactor status command? Trying to script some dev tools around the dev transactor and can't see an obvious way to check whether it's running or not

I mean, there's always ps | grep datomic but I'm hoping for something slightly less janky

I do see a pidFile system property, but I can't seem to find the pid file in the dev transactor

@timgilbert why not just ask your process manager?

e.g for systemd, systemctl status datomic.service

or even is-active

(which gives a useful 0 exit code)

I would do that on my actual transactor server, but locally I'm just running a script to start it (os/x)

ah

Maybe I just need to add a pidfile argument in the config for local, though then I'll need to get the engineers to agree on a path

I don't think the pid is removed on death

although I guess a wrapper script could do it

Hmm, was afraid of that. I suppose for catastrophic failure it couldn't be anyways

Well, I'll mess around with it some

you could make a launchd agent too

although I don't know the details

I suppose so, but I'd need to get over my burning hatred of launchd first

http://tgk.github.io/2012/11/installing-datomic-transactor-with-launchd.html

that's for a daemon (system-wide) not an agent (user-specific)

but probably not very different

Yeah, I can enthusiastically state that I won't be editing any XML to get this little script working. 😉

But I do appreciate the suggestion

you can use the plist editor

I think I would probably attempt to get the dev transactor running in docker before going down that path

your call

I am enjoying my hatred of launchd too much to let go of it, unfortunately

an agreed-upon pid with a wrapper script that deleted the pid would probably work too

it's just nice to have job control and not have to keep a terminal open somewhere

That's true. I wind up doing a lot of my day-to-day work in-memory and then go from there to ddb, typically. But since I can't restore from ddb to in-memory, I'm starting to mess with the dev transactor more

ah. this may interest you then https://gist.github.com/favila/785070fc35afb71d46c9

It's old (from before mem db had logs)

nowdays I think you could just replay the log

Oh, interesting. I will definitely check it out

Looks like 0.9.5561.50 added a feature “health check endpoints for transactors and peer servers.” Details: http://docs.datomic.com/transactor.html#sec-1-1