Flush DNS Cache

To flush DNS cache? Easy like that:

# Linux
1) Flush DNS – “Auto”

service nscd restart

2) Flush DNS – “Manual”

service nscd stop
rm /var/db/nscd/*
service nscd start

# Windows
1) Flush DNS

ipconfig /flushdns

For quick referece: http://www.cyberciti.biz/faq/rhel-debian-ubuntu-flush-clear-dns-cache/



Adding datafile hang on “enq: TT – contention”

Yesterday a colegue asked me about “enq: TT – contention” event on his session that is adding a a datafile in a tablespace wich run out of space in a Database.
I’ve faced this situation another time and decided to document it.

Oracle refer Bug 8332021 : CANNOT ADD A DF WHEN SESSIONS ARE REPORTING ORA-1653 ON for this situation.

The pointing solutions are:
– “Apply Patch 8332021”
– “Alternatively, you can upgrade to or higher as the patch is included in the patch set.”

The not documented workaround (just for you, by Matheus :D) is:
– Cancel session adding datafile.
– Extend any datafile to resume sessions waiting (in resumable state).
– Readd datafile.
This extend action relieves the blocks and will allow you to add the datafile.