PostgreSQL is an Object Relational DataBase Management System. It is Free Software available from http://www.postgresql.org It is thought that all PostgreSQL releases higher than 7.0 work fine with PyKota. Usually PostgreSQL's default configuration is not optimal, but works even on small machines. To achieve better performance, you'll want to modify some settings. For example, here's what I've put in my 'postgresql.conf' file on my Dual-PIII 1Ghz machine with 1 Gb RAM with PostgreSQL 7.4.x : - 'shared_buffers=16384' - 'sort_mem=131072' - 'vacuum_mem=131072' - 'effective_cache_size=32768' - 'log_statement=false' *IMPORTANT :* Don't try to modify these settings if you don't understand what they do. Please give a look at http://www.varlena.com/GeneralBits/Tidbits/perf.html and http://www.postgresql.org/files/documentation/books/aw_pgsql/hw_performance/ for more details. Finally, if you've got several thousand users which you plan to delete in a single shot, increasing the 'max_expr_depth' value (PostgreSQL 7.x) or the 'max_stack_depth' value (with 8.x) may be required. And don't forget : whenever you modify PostgreSQL's configuration files, you have to restart PostgreSQL.