Installation scenarios of Postgres 8.4.8

Failure scenarios related to the database backup and restore operation in
upgrade installation of postgres 8.4.8
Failures during the database backup operation
The upgrade installation of the products such as SFM supporting postgres 8.4.8 may sometimes
involve situations where the products are upgraded from the version containing postgres 7.4.2 to the
corresponding higher version having postgres 8.4.8 version. In such an instance, the upgrade
installation is expected to perform the database backup and restore operations automatically to
ensure that the user data is not lost during the change in the supported version of the postgres
database.
However sometimes, the automatic backup and restore operations are not performed successfully
which can be attributed to many reasons like failed database connection, exceptions etc.
The installation of the product however ensures that appropriate error message or NOTE(s) are
provided under different scenarios to the end-user to take the manual steps if required for updating
the database. Under no failure scenario, the end-user data is expected to be lost during the upgrade
installation.
NOTE: Under certain scenarios, the installation fails to perform the backup and restore operations for
the end-user. Under such cases, when the automatic backup/restore operation fails, user may perform
certain manual steps to restore the data later. However failing to do so will provide the end-user with
the empty database. User will not be able to see the older data in such scenario.
Failures during the database backup due to missing binaries and data availability
In this upgrade scenario, the binaries of the already existing lower version of the postgres (ie, 7.4.2) are
missing from the test setup but the data part is available. In such a scenario, the data recovery is
handled manually using the backup and restore steps. Since the binary files (<DB_PATH>) for the
postgres 7.4.2 are missing, taking the automatic backup of the postgres 7.4.2 database files will not be
feasible. If the installation seeks such a case, a suitable NOTE is provided to the end-user to inform that
there is a potential risk of losing the important user data (the events in the database).
The detail of the NOTE is displayed below:
Cannot take the database dump because postgres binaries are missing in the current installation.
Continuing with installation without data backup. Data recovery may require additional manual steps.
Installing the product with the version 8.4.8 on the system where already the data related to the
postgres 7.4.2 version is available but the binaries are missing, the installation will give the above
described information in the form of a NOTE to the end-user and the data related to the postgres
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