PGA_AGGREGATE_TARGET

 PGA_AGGREGATE_LIMIT can be set to 0 either in a parameter file or dynamically after startup. If a value of 0 is specified, it means there is no limit to the aggregate PGA memory consumed by the instance.

Oracle GG, how to skip a failing transactions? The Replicat is in ABBEND mode

 >START REPLICAT replicate_name SKIPTRANSACTION

How to install oracle 19c in silent mode? This is useful to overcome the Xterm issue

 ./runInstaller -silent -ignorePrereqFailure -waitforcompletion -responseFile /u01/app/oracle/soft/install/response/db_install.rsp -debug

How to shrink datafiles, when you need to rebuild tables/indexes, or move LOBs around

 Below are 2 links with very good explanations, thanks to Jonathan Lewis!!!

https://jonathanlewis.wordpress.com/tablespace-hwm/

https://jonathanlewis.wordpress.com/2010/02/06/shrink-tablespace/

These help when you get:

ORA-03297: file contains used data beyond requested RESIZE value

but there is a lot of free space in the datafile, just not compacted.