Re: Strange trace files generated in RDBMS 19.6.

FYI.. the problem was related to In-Memory...and was fixed with

ALTER SYSTEM SET "_inmemory_dynamic_scans"=DISABLE;

Explanation here :
https://docs.oracle.com/en/database/oracle/oracle-database/18/inmem/in-memory-column-store-architecture.html#GUID-4DDD1A53-D634-4201-B46F-626DAE16A447

A lightweight thread is an execution entity that helps to parallelize full table
scans. It is “lightweight” because it does not incur the higher memory overhead of Oracle processes.

Note:
A lightweight thread used by IM dynamic scans is not the same as a regular thread in the multithreaded Oracle Database model.

Lightweight threads share the resources of the parent foreground or PQ process,
called the table scan process, that coordinates the scan of a set of IMCUs. Threads maintain their own independent flow of execution. The database can parallelize scans by prioritizing threads and executing them asynchronously.

For eligible queries, the process allocates a pool of threads. Resource Manager
automatically determines the number of threads in the pool based on the CPU count in the database host and the current load on the system.

*The pool of threads remains available to the session for subsequent queries unless the idle time reaches an internal threshold, at which point the database terminates the threads. *
^---(*) the threads terminate themselves

Communication between threads occurs exclusively within a process. For this reason, contention does not occur at the database instance level.

We shall file a bug report to avoid the excessive trace file generation that really makes no sense here, it is not an error condition, it is an informational trace file.

regards.

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