Re: what's "enq:TX - contention

Several options, for example:

session 1 - execute some dml without commit

session 2 - alter tablespace X read only;

The tablespace cannot go read only until all current transactions commit - so session 2 picks the oldest current transaction and waits on it using a TX mode 4.

The wait in 10g will show as "TX - contention"

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

• Original Message ----- > Date: Thu, 29 Nov 2007 16:05:00 +0800 > From: "Eagle Fan" <eagle.f_at_gmail.com> > Subject: Re: what's "enq:TX - contention" > > any comments? > Thanks > > On Nov 27, 2007 12:19 AM, Eagle Fan <eagle.f_at_gmail.com> wrote: >
  >> hi:
  >>
  >> In 10g, oracle has four TX wait events:
  >>
  >> 1. enq:TX - row lock contention
  >> 2. enq:TX - index contention
  >> 3. enq:TX - ITL
  >> 4. enq:TX - contention
  >>
  >> I know the first three ones' meanings.
  >>
  >> But what does the last one "enq:TX - contention" mean? I know it means
  >> other TX enqueue types. But what's the *other* TX enqueues?
  >>
  >> Could anybody give me some examples? We have insert sql causes this TX
  >> contention.
  >>
  >> I searched metalink and oracle-l, but most doc/threads are discussing the
  >> first three ones.
  >>
  >> Thanks a lot.
  >>
  

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