[Refdb-devel] upgrading the main database

[Markus H. <mar...@mh...>]

Hi,

the current SVN version (revision 167) implements a first stab at the
main database upgrading mechanism required for smooth upgrades of
packages and ports. It is currently only implemented for
SQLite/SQLite3, but the implementation for MySQL and PostgreSQL is
mainly monkey business. I'll try to add that code during the next
week.

In addition to the standalone and daemonized ways of running refdbd
there is an additional mode now. You can use it to either check the
database connection or to upgrade an existing main database. In both
cases refdbd will evaluate <prefix>/etc/refdb/refdbdrc as usual, so
you may get away using the existing connection parameters.

To check the connection to the database engine and to read out the
version of the main database, run something like this:

refdbd -c -D sqlite3 -e 0 -l 7 -i /path/to/db 2>&1|grep "version:"

refdbd will display some messages and exit. Similarly, to upgrade an
existing main database, run something like this:

refdbd -a -D sqlite3 -e 0 -l 7 -i /path/to/db

David, if you use the latter in your Debian package postinstall
script, you may have to explicitly name the database engine and the
default database location as shown here because the user may have
changed these settings in refdbdrc after the package was installed. Of
course you'd run it without dumping the debug log messages to the
screen.

In order to make the upgrades possible in future releases I've
versioned the refdb dump files. That is, refdb.dump.sqlite(.in) was
renamed to refdb.2.dump.sqlite(.in) and so on. Future releases will
probably have to provide several dump files of older database versions
in order to allow upgrades from these older versions.

Please give the upgrade code a try. I use a 0.9.7 version to create
the database and to add a few styles. Then I try to upgrade it with
the current SVN version. Finally I read out the styles with
the SVN version. So far the tests looked ok.

regards,
Markus

-- 
Markus Hoenicka
mar...@ca...
(Spam-protected email: replace the quadrupeds with "mhoenicka")
http://www.mhoenicka.de