Why are you getting so many gigantic tracefiles with Oracle 12c?

40 gigs of tracefiles per day? No problem, Oracle 12c can generate that for you!

This might be because of the new “feature”

What a nice surprise!

You can see in the tracefiles

—– Cursor Obsoletion Dump sql_id=490jdsadiwssa —–

You can find a support note at My Oracle Support:

MOS Note:1955319.1;
Huge Trace Files Created Containing “—– Cursor Obsoletion Dump sql_id=%s —–“

Oracle introduced an enhancement for a bug in Oracle 12.1.0.2 for dumping more information about obsoleted parent cursors and child cursors after parent cursor has been obsoleted

There’s an underscore parameter to control this dumping.

alter system set “_kks_obsolete_dump_threshold” = <N>;

You can use value 0 to disable cursor dumping entirely, otherwise specify  a value for N, which  tells to generate a dump only after how many times the cursor has been invalidated.