Oracle Scratchpad

July 4, 2013

12c trivia

Filed under: 12c,Infrastructure,Oracle — Jonathan Lewis @ 4:51 am BST Jul 4,2013

Weighing in at a massive 54 characters – the longest parameter name in 12c is:

  • _adaptive_scalable_log_writer_disable_worker_threshold

Followed very closely by (you guessed it)

  •  _adaptive_scalable_log_writer_enable_worker_threshold

Update (June 2017)

And now the even longer (56 characters):

  • _sqlexec_join_group_aware_hj_unencoded_rowsets_tolerated

Update (Jan 2022)

In 19.11 the new record (57 characters) for a parameter name now goes to:

  • _bug30346330_hang_sess_enq_wait_blocked_session_threshold

In a new category we have the longest description (224 characters),  which is for parameter:

  • _kxdbio_disable_offload_opcode

whose description, at 53 characters more than the runner-up) is:

  • KXDBIO Disable offload for the set opcodes. Value is a Bitmap of 0x00000001- disable cell to cell data copy offload 0x00000002 – disable disk scrubbing offload to cell 0x00000004 – disable offloaded writes to cell


There are a lot of “_bug%” parameters in the latest updates of 19c (the first one appeared in, possibly taking over as a substitute for the fix_control mechanism (though there are still 1,556 fix controls in










  1. _adaptive_scalable_log_writer_enable_worker_threshold what the function or role of this parameter parameter

    Comment by feras — July 4, 2013 @ 9:06 am BST Jul 4,2013 | Reply

    • I wasn’t planning to say anything about them – there are 3,333 parameters to worry about and once you get started it’s hard to stop – but the descriptions are:

      Increase in redo generation rate as a percentage
      Percentage of overlap across multiple outstanding writes

      I mentioned the new log writer slave processes a few days ago, I think these parameters tell Oracle when to start or stop dispatching writes to the slaves based on work rates and some measure of how close to each other in the log files the writes are.

      Comment by Jonathan Lewis — July 4, 2013 @ 9:23 am BST Jul 4,2013 | Reply

  2. Hi,

    Thanks for the blog, I use it a lot.

    I was wondering if you have come across my issue as well: I can not re-create the same schema/application on a stand alone, non-container/pluggable 12c at all. Also any attempt to drop either the original (healthy) schema or the “clone” (incomplete – because the process fails during creation) fails too.

    They both generate the same error :”ORA-04043: object SYS_PLSQL_1FDD532D_2935_1 does not exist.”

    The schema does contain packages relying on “versioned” types for pipelined functions, so it feels like it should be a case of “issue 3” mentioned here ( but I’ve got no synonyms. Also no references of the missing type, or its other “versions” can be traced in dba_dependencies …

    I wonder if Oracle has introduced a limitation, in favour of picking up (or actually forcing developers to use) pluggable DBs, and create one pluggable DB per application (previously “schema”).

    What do you think?


    p.s. By the way, I have not been able to import any schemas (whether created originally in 12c, or exported from an 11g schema) into 12c …

    Comment by Babak Tourani — July 19, 2013 @ 4:15 pm BST Jul 19,2013 | Reply

    • Babak,

      I haven’t looked at anything like your scenario – but my default position is: “things break when you mix features” (pluggable and versioning might, by themselves, be sufficient to find holes – but I haven’t got that far yet, I’m still breaking simple things ;).

      If you haven’t tried it already, I would try to write a script creating the smallest possible schema where the problem appeared, and ship it to Oracle.

      U would be a little surprised if Oracle had tried to force developers to use a pluggable DB per application – especially since it’s a licensed option – but all things are possible (sometimes by accident).

      You’ll have to be a little more specific about the import problem – viz: exactly how you did the export, how you did the import, and what you did in between. That’s one that might be more appropriate as a question on the OTN General Questions forum:

      Comment by Jonathan Lewis — July 24, 2013 @ 1:18 pm BST Jul 24,2013 | Reply

  3. […] one of these parameters is now the record holder for “longest parameter name”, the longest description belongs to a hidden parameter that […]

    Pingback by 19c Trivia | Oracle Scratchpad — January 12, 2022 @ 11:06 am GMT Jan 12,2022 | Reply

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