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transactional Lock type TX TM, UL (merged 2) [message #413691] Fri, 17 July 2009 01:40 Go to next message
casttree
Messages: 83
Registered: August 2008
Member
I am trying to understand more for transactional lock type TM, TX, and UL.

Looks like if I lock one table in exclusive mode, (like lock table emp in exclusive mode" in two sessions , we can get TM lock. Can we get the lock type TX and UL easily?

Thanks,
Re: transactional Lock type TX TM, UL (merged 2) [message #413694 is a reply to message #413691] Fri, 17 July 2009 02:05 Go to previous messageGo to next message
Michel Cadot
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Registered: March 2007
Location: Nanterre, France, http://...
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You get a TX lock as soon as you modified a row, for instance.
You get a UL lock using DBMS_LOCK package.

Regards
Michel
Re: transactional Lock type TX TM, UL (merged 2) [message #413853 is a reply to message #413691] Fri, 17 July 2009 17:17 Go to previous messageGo to next message
casttree
Messages: 83
Registered: August 2008
Member
Thanks, how about the lock type in RAC?

If I login Rac Inst 1 as scott and "lock table EMP in exclusive mode" and then login RAC Inst2 and "lock table EMP in exclusive mode" , they should issue the block session?

also one more question for SQ lock, any examples for SQ lock?

Thanks,
Re: transactional Lock type TX TM, UL (merged 2) [message #413885 is a reply to message #413853] Sat, 18 July 2009 01:07 Go to previous message
Michel Cadot
Messages: 64153
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Quote:
how about the lock type in RAC?

No change. Locks are holding marks on database objects, it does not matter you have one or many instances.

Quote:
how about the lock type in RAC?

You get a SQ lock when you ask for a sequence number and Oracle has to generate new numbers in cache and update sys.seq$.

Regards
Michel

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