PostgreSQL feels like Oracle minus lots and lots and lots of administration overhead. You don't have to create table spaces, it just uses files in your Unix volume. Installation takes 30 seconds if you use a Debian package or RPM, from deciding to install, to being in psql (the equivalent of sql*plus).From a DBA perspective, Postgres still has live backups, multi-gigabytes data sets, fine-grained locking, and the like.From an application construction perspective, Postgres does not have a lot of the bells and whistles that Oracle does: it doesn't automaticallly integrate with foreign data sources, it doesn't have a JVM or a web server built in.Of the items you mentioned:pl/sql: pgsql has a procedural language that is reminiscent of Oracle's.query optimization: you can build indices, e.g. CREATE INDEX foo ON function(table.colume) will build an index on that function's output.packages - ?data dictionary - ?. If you mean whether the database can be self-describing, there is a COMMENT ON command that survives dump/reload.Dynamic performance views - ?unusual indexes - this is pgsql's bread and butter.index-organized tavles - see pgsql's CLUSTER and VACUUM.I've installed both postgres and oracle. Postgres has far, far fewer sharp edges. There are fewer features that would appeal to your average bank, but it's good enough for about 85% of the installations I can imagine.