Reusing existing content db (or other db's?)

[grtjn]

If you point from two Roxy project to a shared content db, both will try to create, update, and delete that content db. You can trick one project by added a custom property, for instance shared-content-db, point to that in ml-config.xml for the http-server settings, and remove the content-db part entirely, but a small flag alike install-xcc=false might be more convenient..

One might also have a good reason to want to share a modules-db. A similar thing would account there. How about some extra flags:

• install-modules-db=false
• install-content-db=false

Maybe more?

[grtjn]

Hmm, slight rectification. The shared-content-db approach only works with install-xcc=false, and maybe a few other command/settings also rely on content-db being present. Perhaps better to keep using content-db setting, but do remove the entire content-db settings part from ml-config.xml. That should prevent it from being included in bootstrap and wipe.

[grtjn]

A slightly different approach could be something like this:

• shared-databases=${content-db},${extra-db}
• shared-servers=..
• shared-users=..
• shared-roles=..
• etc

[hutchkintoot]

+1 being able to do this would be really useful.

[grtjn]

Yet slightly different approach would be to add a shared="true" parameter inside ml-config.xml. It would make it get created at bootstrap (only if missing), and skipped on wipe. An extra param --wipe-shared would force wiping shared stuff..

[grtjn]

You can already get there partly, by specifying a content-db name that already exists, and then removing database + assignments for that database from ml-config. It won't get created, won't get wiped. It must exist upfront..

[dmcassel]

Would it be sufficient to document the "removing the database assignments" approach, perhaps on the Database Configuration wiki?

[grtjn]

I like the idea of having that shared=true flag in ml-config. It sounds versatile, and should be relatively easy to implement. But a section on that wiki sounds like a good idea too, and perhaps quickest to provide..

[grtjn]

Looking back over this and related tickets my current thinking is not in favor of having configs or flags that tell Roxy something is shared. The reason is that I think it would be confusing if the content-db section is still within ml-config, despite it not doing much, or maybe nothing at all. A shared=true flag can be overlooked easily, but if the content-db section is completely removed, no confusion about whether that project creates/configures the db or not..

I opened this wiki to document the approach in more detail: https://github.com/marklogic/roxy/wiki/Using-an-existing-Content-Database

Same principle should also work for the other db's..