Postgis 2.1 error after update [closed]

Question

After a usual update progress - "apt-get upgrade" - I can not connect with qGIS to my PostGIS DB anymore.

Error in the qGIS logfile:

Your database has no working PostGIS support. 
Erroneous query: SELECT postgis_version() returned 7 [ERROR:  could not load library "/usr/lib/postgresql/9.3/lib/postgis-2.1.so": liblwgeom-2.1.2.so: cannot open shared object file: No such file or directory]
Retrieval of postgis version failed

After asking for my version using SELECT PostGIS_full_version(); This occured:

ERROR:  could not load library "/usr/lib/postgresql/9.3/lib/postgis-2.1.so": liblwgeom-2.1.2.so: cannot open shared object file: No such file or directory 
CONTEXT:  SQL statement "SELECT postgis_lib_version()" 
PL/pgSQL function postgis_full_version() line 19 at SQL statement

How can I fix that?

Thats my environment: xUbuntu 14.04, PostgreSQL 9.3, Postgis 2.1, QGIS 2.3,

Answer 1

As you can read here it could be a bug of the upgrade procedure.

Waiting for fixing I advise you to can follow the workaround:

apt-get remove postgresql-9.3-postgis-2.1 liblwgeom-2.1.3 liblwgeom-2.1.2 postgis

The actual versions can be other than in the example. Use commands like this to find the packages to remove:

dpkg -l | grep liblwgeom
dpkg -l | grep postgis

Followed by:

apt-get install postgresql-9.3-postgis-2.1

Answer 2

Check if the specified files do exist. According to the messages, apparently the postgis library does not exist. Try reinstalling postgis again.

Remember to backup your database frequently.