Install PostgreSQL into pgsql conda environment.

[yakutovicha]

fixes #48

[csadorf]

@yakutovicha Looks like you need to update the branch?

[yakutovicha]

@yakutovicha Looks like you need to update the branch?

and downgrade PostgreSQL :)

[csadorf]

@yakutovicha Looks like you need to update the branch?

and downgrade PostgreSQL :)

Indeed, it is actually not quite clear to me what exactly this PR is trying to achieve. To my understanding it is perfectly fine to use the OS-provided distribution of PGSQL as our main database process, we just need the second installation for the migration. However, this PR seems to generally install PGSQL via conda. Why?

[yakutovicha]

Indeed, it is actually not quite clear to me what exactly this PR is trying to achieve. To my understanding it is perfectly fine to use the OS-provided distribution of PGSQL as our main database process, we just need the second installation for the migration. However, this PR seems to generally install PGSQL via conda. Why?

Well, I wrote the motivation in the issue. The only thing that I could add is that PGSQL=10 is not available in Ubuntu 20/22.

[csadorf]

Well, I wrote the motivation in the issue. The only thing that I could add is that PGSQL=10 is not available in Ubuntu 20/22.

But aren't you replacing the main database installation here which we actually want to be a newer one that is supported by Ubuntu 20/22?

[yakutovicha]

Well, I wrote the motivation in the issue. The only thing that I could add is that PGSQL=10 is not available in Ubuntu 20/22.

But aren't you replacing the main database installation here which we actually want to be a newer one that is supported by Ubuntu 20/22?

I would like to downgrade the PGSQL to version 10 because this version is used in all stable AiiDAlab images out there. Once this PR is merged I am going to immediately release a new aiida-prerequisites image and make a PR to aiida-core. Once a newer version of AiiDA is released, we can base the aiidalab-docker-stack on top of it without any problems.

At the same time, I will continue solving the migration issue.

I hope that makes sense

[csadorf]

I hope that makes sense

Unfortunately, not. You say that this effort is part of #44 which is about creating the migration. Why would we need to downgrade for that? We only need a second installation with an older version, no?

Further, you convinced me yesterday that we should press forward with the migration and that trying to get back into a good state on the aiidalab image does not really make sense. Especially since we can always create a new aiidalab image release by simply basing it on an older version of the aiida-core image (e.g. via aiidalab/aiidalab-docker-stack#270).

So we don't need to downgrade the database for the migration nor for creating a new aiidalab release. 😕