Bug#986975: libgdal28: please add Breaks: libgdal20

[Sebastiaan Couwenberg]

On 5/19/21 9:29 PM, Dennis Filder wrote:
> The error message I get when trying to dump a
> database from the old 11 cluster is:
> 
>   pg_dump: error: query failed: ERROR:  could not access file "$libdir/postgis-2.5": No such file or directory
> 
> Is that fact communicated somewhere?  Or are postgis users just
> expected to know this? 

PostGIS users are expected to know this. This is an infamous issue with
PostGIS as an extension to PostgreSQL which makes it pretty shit
compared to MySQL/MariaDB which has geometry support out of the box.

The upstream docs only support upgrading the PostgreSQL database with
the same version of PostGIS (because the version is embedded in the
extension filename):

"
 Install the new version of PostgreSQL and the same version of PostGIS
 you are using in your old database. You need to match the PostGIS
 version so that the dump file function definitions reference an
 expected version of the PostGIS library.
"

 https://postgis.net/workshops/postgis-intro/upgrades.html

Because this is not possible during a distribution upgrade where both
the version of PostgreSQL and the version of PostGIS change, you need to
resort to hacks to make the upgrade work:

 http://blog.cleverelephant.ca/2016/08/postgis-upgrade.html

Or just recreate the databases from scratch. It has the benefit that you
don't need twice the amount of disk space, you can just drop the old
cluster and use the disk space for the new cluster only.

Kind Regards,

Bas

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