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RE: Rebuilding MLOG tables

From: Sarnowski, Chris <>
Date: Thu, 12 Jun 2003 12:48:36 -0700
Message-ID: <>

I don't think it will do quite what you want it to, since the 'alter table move' statements are DDL so will release the lock.

I just tried this experiment in 2 SQLPlus windows:

SQL 1.1> lock table blah in exclusive mode; returns with
Table(s) Locked.

SQL 2.1> insert into blah values (1);
(this waits)

SQL 1.2> alter table summ_snapshot move tablespace tools_data; returns with
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT specified

but this is enough to release the first lock, because 2.1 now returns with 1 row created.

On the other hand the move should be harmless. I see someone else has given a response with the same ultimate moral, but I'll still post, to point out the lock behavior.

> -----Original Message-----
> From: Stephen Lee [mailto:[EMAIL PROTECTED]
> Sent: Thursday, June 12, 2003 3:55 PM
> To: Multiple recipients of list ORACLE-L
> Subject: Rebuilding MLOG tables
> Among some of the "Rube Goldberg" applications around here,
> is one that has
> multiple replication clients that subscribe to a master. For whatever
> reason, we might have a client not update for a while and the
> MLOG table(s)
> get big. Then, after that, every update has to read up to
> sky-high high
> water mark. From the looking around we have done, the thing
> to do to get
> the HWM back down without rattling replication seems to be
> (during a time
> when we know no updates are going into the master):
> lock table xyz in exclusive mode;
> alter table mlog$_xyz move tablespace over_there;
> alter table mlog$_xyz move tablespace back_here; (optional, I suppose)
> rollback; (release the lock)

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Author: Sarnowski, Chris

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Received on Thu Jun 12 2003 - 14:48:36 CDT

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