Yudi,
It's been a couple of years since I last worked with PostgreSQL and
I will admit that as an open source db. It's rather good and more like
Oracle than any other, but there are differences that can be troublesome.
1) the root of a PostgreSQL database is a filesystem location.
From there your rather limited in what you can do by the size of the
mount point. You can create a number of "databases" which are analogous
to tablespaces, but they cannot span mount points. Most troublesome in
my view is the PostGres community's overwhelming demand that the
database be owner by postgres and the executable's by root. There are
ways to get around this but as soon as you do it gets harder to get
support from the community and those commercial vendors that provide
support. The argument is that with the executables under root it's
harder for someone to mess with them. My issue here is that every
machine has a root account that is every hacker's target, and once your
logged in as root you own everything on the machine. I've seen where a
hacker got access to a login prompt on a web server and tried for a long
time to connect as oracle. The problem was it did not exist so all he
did was activate an alarm.
2) Everything in PostgreSQL is case sensitive, so MYTABLE is
different from MYtable and mytable. I've also seen that at the column
level where there was a SEQ_no and a SEQ_NO column in the same table.
3) What we call REDO in Oracle is implemented very differently in
PostGres. Make sure you have the vacuum deamon on and scheduled at a
reasonable interval.
4) Stored PLSQL is rather different as well. You have to specify
the language the function/procedure is written in with the "LANGUAGE
PL/SQL;" identifier.
5) In the version I was working with Partitioning was nonexistent.
6) Their equivalent of OEM is not web enabled.
7) Recovery is similar, but different and definetly needs practice,
so have a as play system available.
8) There are a number of books on PostgreSQL 15 & 16 on Amazon. I
HIGHLY recommend you obtain one that covers the version your working on
and than develop some use cases for your own edification
Richard Goulet.
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