minetestserver -migrate and postgresql?

[ExeterDad]

I finally managed to build a .deb package with postgresql support. Cmake bug upstream prevents postgresql detection.
I'm wanting to convert my sqlite map to postgresql with the -migrate option. I've done it without issues in the past with redis, but unsure how to go about it with postgresql. I'm not even sure if migration is supported yet with postgresql. If so, do I need to supply a connection string somewhere? Or would it use some sort of defaults?

Googling Minetest and postgresql yeilds sparse results as it seems very few people are using postgresql as their backend.

Insight would be greatly appreciated. Examples would be awesome as well.

Thanks!

[ExeterDad]

So apparently minetestserver does support migrating from sqlite to postgresql. Yeay!!!

After much fiddling with various conversion tools without any luck, I went for it with my local instance of our server. Good thing I did as there was MUCH trial and error while I was figuring it out. I'm going to outline what I did for others (or even myself) to get it working for them. I know nothing about postgresql other than I learned today so feel free to pick this tutorial apart so I may edit this post.

Our server is running Debian Jessie completely Vanilla, with only what is required to build and run minetest server so your results may be quite different than mine.

First off, you need minetestserver with postgresql support intalled. I had already built and rolled minetest in a .deb package for easy install and clean removal. I just need to install it for the first time but not start it yet:

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sudo dpkg -i minetest_0.4.15-dev-20170215_amd64.deb

Now install postgresql and client:

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sudo apt-get install postgresql-9.4

This installed:
postgresql-9.4
postgresql-client-9.4
postgresql-client-common
postgresql-common

Check to see if postgresql server is up and running. There will be a bunch of output if this command is run and the server is up:

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ps -ef | grep postgre

On a Debian box, user postres is created. In the *nix terminal we need to become that user and run the postgresql client to connect and create a user, password and database for our map.

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sudo -u postgres psql

The prompt will change appearance when you are in the client. Type \q to quit if you change your mind.

I'm now going to create a new database user "minetest" with a password of "12345" and give minetest all privs on a new database called "myworld". Use whatever you like... maybe not such a lame password though.

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postgres=# CREATE USER minetest WITH PASSWORD '12345';
postgres=# CREATE DATABASE myworld OWNER minetest;
postgres=# GRANT ALL PRIVILEGES ON DATABASE myworld TO minetest;

The postgres=# portion of the above lines is the client "prompt", don't type that part. Also note, the uppercase commands must be uppercase. The semi-colons ";" must not be omitted. If they aren't included, it will be assumed you are typing a extra long command.

Check to make sure the new database is there and owned by new user "minetest". List the databases with \l <--- backslash and a lowercase "L":

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postgres=# \l
                             List of databases
   Name    |  Owner   | Encoding | Collate | Ctype |   Access privileges   
-----------+----------+----------+---------+-------+-----------------------
 myworld  | minetest | LATIN1   | en_US   | en_US | =Tc/minetest         +
           |          |          |         |       | minetest=CTc/minetest
 postgres  | postgres | LATIN1   | en_US   | en_US |
 template0 | postgres | LATIN1   | en_US   | en_US | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
 template1 | postgres | LATIN1   | en_US   | en_US | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
(4 rows)

Hopefully everthing is good, now exit the client with \q

Now we create a connection string in our worlds world.mt file. Do not change the backend string from sqlite yet. The migration will do that for you when it's done.
So the top part of world.mt should look like this:

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gameid = minetest
backend = sqlite3
pgsql_connection = host=127.0.0.1 port=5432 user=minetest password=12345 dbname=myworld

Save world.mt and let's start minetestserver and begin the migration. Launch it with the --migrate option, and --world option. I always use the full path to the world directory in quotes when launching via cli. Your path will be different naturally. Mine is in my user directory. So I don't have to deal with permissions when editing stuff.

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minetestserver --migrate postgresql --world "/home/leeh/.minetest/worlds/myworld"

You should expect to see something like this if all went well:

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leeh@s103139:~$ minetestserver --migrate postgresql --world "/home/leeh/.minetest/worlds/myworld"
2017-02-16 21:08:37: WARNING[Main]: Couldn't find a locale directory!
2017-02-16 21:08:37: WARNING[Main]: Your PostgreSQL server lacks UPSERT support. Use version 9.5 or better if possible.
 Migrated 880260 blocks, 99.2227% completed.
2017-02-16 21:10:24: ACTION[Main]: Successfully migrated 887156 blocks
2017-02-16 21:10:24: ACTION[Main]: world.mt updated

Now you can start your server with your usual method and it should "just work"

Enjoy!

[googol]

Can rewrite your post to the wiki?
Interesting to redis too.