ORA-600 [kggsmGetString:1]

Hi all!
So, checking on this error, found the following relevant reference: ORA-600 [kggsmGetString:1] (Doc ID 1541187.1).
Once it was during a SQL running, the only match could be Bug 17235420 – ORA-600 [kggsmGetString:1] with adaptive cursor sharing (Doc ID 17235420.8).

The problem?
No detailed information, no workaround, only patches to apply. The only information is “ORA-600 [kggsmGetString:1] can occur in 12c if adaptive cursor sharing is used.

So, checking on SQL Plan details, could see it’s using the following adaptive optimizations:

Note
-----
   - dynamic statistics used: dynamic sampling (level=2)
   - statistics feedback used for this statement
   - this is an adaptive plan (rows marked '-' are inactive)
   - 2 Sql Plan Directives used for this statement

MOS note Recommendations for Adaptive Features in Oracle Database 12c Release 1 (Adaptive Features, Adaptive Statistics and 12c SQL Performance)” ID 2312911.1 recommends to apply Oct 2017 BP or one-off patches to disables adaptive statistics only.

In this case, the easiest solution is to disable both, adaptive plans, as this release only has one parameter to control that – optimizer_adaptive_features which defaults to TRUE.

And it’s online:

SQL> show parameter adaptive

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
optimizer_adaptive_features	     boolean	 TRUE
optimizer_adaptive_reporting_only    boolean	 FALSE
parallel_adaptive_multi_user	     boolean	 TRUE
SQL> alter system set optimizer_adaptive_features=false scope=both;

System altered.

SQL> show parameter adaptive

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
optimizer_adaptive_features	     boolean	 FALSE
optimizer_adaptive_reporting_only    boolean	 FALSE
parallel_adaptive_multi_user	     boolean	 TRUE

After that, issue solved. ORA-600 didn’t repeated.

Hope it helps!

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