It's hard to do this automatically, because there could be a need for user intervention. There are three ingredients.
there is a file PG_VERSION, containing 10, 13, or whatever else. The script has to decide what to do based on that.
The command is pg_upgrade: 2x bindir and 2x datadir are mandatory, then first do --check to see if it works, then remove it and maybe use --link to make hardlinks. The hardlink variant is quicker, but there is no way back. So, a question here is, should this be done with a safety net or not. I would say yes.
move the current data dir to data-10 for version 10
execute pg_upgrade (first with --check) but without--link, targeting data
if it works, get rid of the backup in data-10 – otherwise remove data, report the problem, and rename data-10 to data and start the DB as usual. Next time, it will attempt to upgrade again.
configuration files. I haven't checked what docker configures, but there were params we had to change in production. wal_keep_size is new, while wal_keep_segments was removed: sed -i "/^wal_keep_segments/d" {PG_DATA}/postgresql.conf.
Oh, and in general, that new data dir must be setup fresh by the same user as the original database. IDK which one docker has, mabye postgres ? In any case, step one for ne new data dir is initdb -U [username], or maybe just the default, and step two is to copy over postgresql.conf and pg_hba.conf – or well, maybe we just write new config files and forget about copying and changing lines.
It's hard to do this automatically, because there could be a need for user intervention. There are three ingredients.
PG_VERSION, containing10,13, or whatever else. The script has to decide what to do based on that.The command is pg_upgrade: 2x bindir and 2x datadir are mandatory, then first do
--checkto see if it works, then remove it and maybe use--linkto make hardlinks. The hardlink variant is quicker, but there is no way back. So, a question here is, should this be done with a safety net or not. I would say yes.data-10for version 10pg_upgrade(first with--check) but without--link, targetingdatadata-10– otherwise removedata, report the problem, and renamedata-10todataand start the DB as usual. Next time, it will attempt to upgrade again.wal_keep_sizeis new, whilewal_keep_segmentswas removed:sed -i "/^wal_keep_segments/d" {PG_DATA}/postgresql.conf.Oh, and in general, that new data dir must be setup fresh by the same user as the original database. IDK which one docker has, mabye
postgres? In any case, step one for ne new data dir isinitdb -U [username], or maybe just the default, and step two is to copy overpostgresql.confandpg_hba.conf– or well, maybe we just write new config files and forget about copying and changing lines.