postgresql-common 181+deb9u2 / etc / apt / apt.conf.d / 01autoremove-postgresql

// File installed by postgresql-common. Currently not updated automatically,
// but might be in future releases.
//
// We mark all PostgreSQL packages as NeverAutoRemove because otherwise apt
// would remove the old postgresql-x.y package when the "postgresql" meta
// package changes its dependencies to a new version, rendering the old
// database cluster inaccessible. As access to the cluster might depend on
// other modules (like datatypes), we use a pretty wide pattern here. We might
// tighten this to match only actually used PostgreSQL versions in the future.

APT
{
  NeverAutoRemove
  {
    "^postgresql-";
  };
};