Re: Performance issue - Library cache lock

 We have stream_pool_size set as ~256MB.

 We killed the specific session and now one of the other sessions which was showing "enq:TQ DDL contention" just before entering into "reliable message wait" and executing below sql. What we are wondering about is that the export used to run daily without any issue , so why is it experiencing such an odd wait today and making the database flooded with concurrency?

 BEGIN sys.kupc$que_int.create_queues(:1, :2, :3, :4, :5); END;

On Fri, Feb 12, 2021 at 5:25 PM Shane Borden <sborden76_at_yahoo.com> wrote:

> This is some sort of a datapump job going on. Do you have enough
> streams_pool configured?
>
> Shane Borden
> sborden76_at_yahoo.com
> Sent from my iPhone
>
> On Feb 12, 2021, at 5:00 AM, Pap <oracle.developer35_at_gmail.com> wrote:
>
> 
>
> Hello All,
>
> We are seeing one of our database nodes flooding with "concurrency" wait
> i.e "library cache lock" and when going back to the start of the wait in
> ASH we are seeing the blocking session actually seems to be from one of the
> export sessions and it's from SYS too. The two sqls which were captured in
> ASH from that session are below. The second one is the one spending time on
> an event "reliable message" with current_obj# showing s '-1' and blocking
> others now. When we see the start of the issue, that session was showing
> current_obj# as index "AQ$_PROPAGATION_STATUS_PRIMARY" for quite a long
> time. Are there any bugs associated with such an issue? This table seems to
> be streams related but we don't use streams in this database, so not sure
> from where it's popping up.
>
> BEGIN
>
> SYS.KUPM$MCP.MAIN('SYS_EXPORT_TABLE_02', 'SYS', 0, 0);
>
> END;
>
> BEGIN sys.kupc$que_int.delete_queues(:1, :2); END;
>
>
>

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