On Fri, Mar 8, 2024 at 4:22 PM David Gauthier <dfgpostg...@gmail.com> wrote:
> Here's the situation.... > > - The DB contains data for several projects. > - The tables of the DB contain data for all projects (data is not > partitioned on project name or anything like that) > - The "project" identifier (table column) exists in a few "parent" tables > with many child... grandchild,... tables under them connected with foreign > keys defined with "on delete cascade". So if a record in one of the parent > table records is deleted, all of its underlying, dependent records get > deleted too. > - New projects come in, and old ones need to be removed and "archived" in > DBs of their own. So there's a DB called "active_projects" and there's a > DB called "project_a_archive" (identical metadata). > - The idea is to copy the data for project "a" that's in "active_projects" > to the "project_a_arhchive" DB AND delete the project a data out of > "active_projects". > - Leave "project_a_archive" up and running if someone needs to attach to > that and get some old/archived data. > > The brute-force method I've been using is... > 1) pg_dump "active_projects" to a (huge) file then populate > "project_a_archive" using that (I don't have the privs to create database, > IT creates an empty one for me, so this is how I do it). > 2) go into the "project_a_archive" DB and run... "delete from par_tbl_1 > where project <> 'a' ", "delete from par_tbl_2 where project <> 'a' ", > etc... leaving only project "a" data in the DB. > 3) go into the "active_projects" DB and "delete from par_tbl_1 where > project = 'a' ", etc... removing project "a" from the "active_projects DB. > > Ya, not very elegant, it takes a long time and it takes a lot of > resources. So I'm looking for ideas on how to do this better. > > Related question... > The "delete from par_tbl_a where project <> 'a' " is taking forever. I > fear it's because it's trying to journal everything in case I want to > rollback. But this is just in the archive DB and I don't mind taking the > risk if I can speed this up outside of a transaction. How can I run a > delete command like this without the rollback recovery overhead ? > >(I don't have the privs to create database, IT creates an empty one for me, so this is how I do it). That's a shame. You can do something similar with tablespaces Template your existing schema to create a new schema for the project (pg_dump -s) Create tablespace for this new project and schema You can then move the physical tablespace to cheaper disk and use symbolic links or... archive and/or back it up at the schema level with pg_dump -n ...as long as you don't put anything in the public schema all you are really sharing is roles otherwise a bit like a separate database
