I’ve run into the wait “kksfbc child completion” a few times over the past but found very little written about it. I don’t have an explanation, but I have something that might be as good – a way to reproduce it. By being able to reproduce I at least test theories about it. I ran a tight loop of
insert into t value(1);
See anything strange? I put “value” instead of “values” so the insert errored out. Thus causing parsing every execute. So this wait seems to be related to parsing. Could run further tests by correcting and adding a different litteral value to the insert to see what kind of waits might result.
Another tell tale sign that there was an error was that I also recieved “SQL*Net break/reset to client” which is a sign of an error in the sql statements that the application is attempting to execute.
oracle-l response was:
From: K Gopalakrishnan <kaygopal_at_gmail.com>
Date: Sun, 11 Feb 2007 02:00:45 -0500
Message-ID: <3b0f44a10702102300h3b9120dh139c030da47878e@mail.gmail.com>
David,
kks is Kompilation Layer function to Find the Bounded Cursor. Typically related to parsing (hard) which sometimes calls kksscl to scan the child list on those cursors when the cursors are shared.
Dion Cho says:
It’s literal meaning is “waiting till building the child cursor completes”, which is naturally related to the hard parse issue and multiple children problem. The main reasons are known to be massive hard parses or library cache bugs.
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