RE: Rollback too small... on analyze???

  • From: "Michael Kline" <mkline1@xxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 16 Feb 2004 08:27:42 -0500

On some of the tables we are talking some 180+ million rows.

There is probably along the line of 16gb of rollback segs.

They do parallel on some of the things, this table I think
they do degree 4, but they change things all the time.

We've been experimenting with various options.

They do have nologging turned on. We have up to 20 parallel
servers.

It's batch job after batch job that combines records from
tables that are perhaps even larger than this to about
8-10 tables from which they make cubes and the like.

Maks.

> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Ryan
> Sent: Saturday, February 14, 2004 9:48 AM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: Re: Rollback too small... on analyze???
>
>
> it does. turn autoextend on for your rollback tablespace to get around the
> problem. Analyze is basically doing a bunch of selects and DML.
> Both require
> rollback.
>
> how many records exist in the table originally? You can radically speed up
> your load by doing
>
> create table /*+ parallel (number) */ <table_name> nologging
> as select
> insert table joined to previous table.
>
> Then drop the old table, rename new table to old table, then issue your
> index creation as dbms_jobs. Can be MUCH faster.
>
> I dont recommend loading just 5 million records at a time. Turn autoextend
> on for your rollback tablespace and do a big insert select. The
> cursor thing
> is lame. I hate that.
>
> see my comments below...
> ----- Original Message -----
> From: "Michael Kline" <mkline1@xxxxxxxxxxx>
> To: <oracle-l@xxxxxxxxxxxxx>
> Sent: Saturday, February 14, 2004 9:28 AM
> Subject: Rollback too small... on analyze???
>
>
> > Oracle 8.1.7.4 on HP-UX.
> >
> > I've got a client trying to insert into large tables in batches of
> > 5 million rows which is taking about 20 minutes per 5 million. No
> > problem there.
> >
> > The problem seems to be that he runs an analyze compute statistics
> > afterwards and about 1 out of 5 times he gets a rollback segment
> > too small. I wouldn't think analyze uses rollback.. It happens
> > so infrequently and ALWAYS seems to work if they simply run it
> > again.
> >
> > What I suspect, though have no way to prove, is that the rollbacks
> > are still dumping out after the last batch of inserts and the
> > analyze gets a bit confused on this.
> >
> > I have suggested they put a 3-5 minute "wait" before they run
> > the analyze and see if that clears the problem up.
>
> dont do this. just turn autoextend on for your rollback tablespace. Its
> easier. you can always shrink it back down after your done.
> >
> > Is there any firm foundation to this?
> >
> > What might be cause this?
> >
> > The only other process running at the time was another insert
> > batch on a different table.
> >
> >
> > Michael Kline, Principal Consultant
> > Business To Business Solutions, LLC
> > Richmond, VA
> > 804-744-1545
> >
> >
> >
> >
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