As some of you have noticed, we ran into disk space problems over the weekend due to the
size of the individual databases the database server currently has to manage. You can use
the following command to retrieve the current size of your own database (replace 'sXXXXXX'
with your user name):
For the project, the size of your database should not exceed the 750 MB mark.
You will not need the tables entry, comment, dbxref, go_term,
feature, and omim for the third assignment. Instead, you are expected to work
solely with the data in the database that you poplulated from the given data in the
second assignment. In order to release to storage space required by the data that
was loaded in the first assignment please drop the respective tables before you start
working on the last assignment:
DROP TABLE entry CASCADE;
DROP TABLE comment CASCADE;
DROP TABLE dbxref CASCADE;
DROP TABLE go_term CASCADE;
DROP TABLE feature CASCADE;
DROP TABLE omim CASCADE;
Note: You can always recreate the tables from the data on the Web in case of an
Note: If you have defined any views on the above tables, these views will be
deleted as well.
Furthermore, you can drop table ukweather after you completed the previous
two assignments. This should free up another +100 MB of disk space.
After dropping the above mentioned tables you should use VACUUM to reclaim
storage occupied by deleted tuples:
VACUUM [ table ]
In normal PostgreSQL operation, tuples that are deleted or obsoleted by an update are
not physically removed from their table; they remain present until a VACUUM is done.
Therefore it's necessary to do VACUUM periodically, especially on frequently-updated tables.
With no parameter, VACUUM processes every table in the current database. With a parameter,
VACUUM processes only that table.
After VACUUM check the size of your database again. It should not exceed
500 MB before you start with the last assignment. If your database is larger than
500 MB you might want to delete additional temporary tables that you created during
the previous assignment.