Re: ORA-12850 running ash_wait_chains against 19c database

Sending an update to this old thread:

I've worked around this ORA-12850 in 19c RAC now, it was about the GV$ PX slaves not being able to reproduce the required plan in a remote instance due to factored subquery materialization, so I just disabled that feature and now ash_wait_chains is not hitting this Oracle bug anymore. I just added INLINE hints to all WITH subqueries in the script, I didn't want to set the *_with_subquery* parameter as this would be an "alter session" and would affect any other queries you may run in your session too:

https://tanelpoder.com/posts/ora-12850-could-not-allocate-slaves-on-all-specified-instancs-error/

--
Tanel Poder
https://tanelpoder.com/seminar


On Thu, Jul 11, 2019 at 10:28 AM Chris Stephens <cstephens16_at_gmail.com>
wrote:



> i went as low as 11.2.0.4 to no avail. just looked at 10053 trace and

> about the only thing i noticed was "mesg=kxfxcp: slave join failed".

>

> On Thu, Jul 11, 2019 at 8:51 AM Andy Klock <andyklock_at_gmail.com> wrote:

>

>> > Chris Stephens <cstephens16_at_gmail.com> writes:

>>

>> > we recently installed 19c GI/RDBMS as a 3 node RAC cluster.

>> >

>> ...

>> > I did some googling and some searching on support.oracle.com to no

>> avail.

>> > I've got an SR open but was wondering if anyone else has hit this and/or

>> > has a solution to prevent the ORA-12850.

>> >

>> > Thanks in advance for any help!

>>

>>

>> I have not, but I'm also not on 19c. The assumption is that the CBO has

>> chosen a plan that requires more slaves than you have available. Perhaps

>> an adaptive plan or something? For a quick and dirty test, try

>> downgrading the optimizer for the

>> session and see what happens.

>>

>> Something like,

>>

>> alter session set optimizer_features_enable = '12.1.0.2'; -- or even

>> lower if you've left the adaptive features enabled

>>

>> Andy K

>>

>


--
http://www.freelists.org/webpage/oracle-l