Oracle X$ tables – Part 1 – Where do they get their data f

Oracle X$ tables – Part 1 – Where do they get their data from? by Tanel Poder Posted on January 10, 2014 It’s long-time public knowledge that X$ fixed tables in Oracle are just “windows” into Oracle’s memory. So whenever you query an

Oracle X$ tables – Part 1 – Where do they get their data from?

by Tanel Poder Posted on January 10, 2014

It’s long-time public knowledge that X$ fixed tables in Oracle are just “windows” into Oracle’s memory. So whenever you query an X$ table, the FIXED TABLE rowsource function in your SQL execution plan will just read some memory structure, parse its output and show you the results in tabular form. This is correct, but not the whole truth.

Check this example. Let’s query the X$KSUSE table, which is used by V$SESSION:

SQL> SELECT addr, indx, ksuudnam FROM x$ksuse WHERE rownum 391513C4