Latest postfix update breaks hash-based aliases.db (potentially other .db files too?)

[d1zzyg]

OS: Ubuntu 8.04.4 LTS
Package: 2.5.1-2ubuntu1.4

Errors were reported during the update:
  postfix/postfix-script: fatal: the Postfix mail system is already running [fail]
  invoke-rc.d: initscript postfix, action "restart" failed.
  dpkg: error processing postfix (--configure):
   subprocess post-installation script returned error exit status 1
  dpkg: dependency problems prevent configuration of postfix-ldap:
   postfix-ldap depends on postfix (= 2.5.1-2ubuntu1.4); however:
    Package postfix is not configured yet.
  dpkg: error processing postfix-ldap (--configure):
   dependency problems - leaving unconfigured
  dpkg: dependency problems prevent configuration of postfix-pcre:
   postfix-pcre depends on postfix (= 2.5.1-2ubuntu1.4); however:
    Package postfix is not configured yet.
  dpkg: error processing postfix-pcre (--configure):
   dependency problems - leaving unconfigured
  Processing triggers for libc6 ...
  ldconfig deferred processing now taking place
  Errors were encountered while processing:
   postfix
   postfix-ldap
   postfix-pcre

Whenever postfix is restarted, the following errors are shown in /var/log/mail.err:
  Jun 22 09:50:04 colossus postfix/local[30997]: fatal: open database /etc/mail/aliases.db: Invalid argument

The *original* version of the aliases.db file gives (file /etc/postfix/aliases.db):
  /etc/postfix/aliases.db: Berkeley DB (Hash, version 8, native byte-order)
... whereas *after* the update it shows version 9.

TEMPORARY FIX: Changing the default_database_type to btree fixes aliases.db, kills the mail.errors and allows postfix to run normally.

[Scott Kitterman (kitterman)]

https://launchpadlibrarian.net/71523987/postfix_2.5.1-2ubuntu1.3_2.5.1-2ubuntu1.4.diff.gz

There's nothing in the update that could cause that. It looks like what you have is a postfix configuration problem unrelated to the package update.