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Home -> Community -> Mailing Lists -> Oracle-L -> Re: production database on aix won't be open, help
Yup. FYI, this is what Metalink says:
A final new feature for
specifying bounded recovery time
is the use of fast-start
parallel rollback. In prior
versions of Oracle, although
database recovery time was
reduced because Oracle could
open the database after the
instance roll-forward process
completed, the transaction
rollback could still take a long
time, particularly for parallel
DML operations, because rollback
had to happen serially. In
Oracle8i, you can specify the
FAST_START_PARALLEL_ROLLBACK
parameter to low or high to
allow SMON to use parallel-query
slaves for parallel rollback,
thus speeding up the rollback
process. Monitoring parallel
rollback can be accomplished
using the V$FAST_START_SERVERS
and V$FAST_START_TRANSACTIONS
views.
And on Technet:
Fast-start parallel rollback is mainly useful when a system has transactions that run a long time before committing, especially parallel INSERT, UPDATE, and DELETE operations. When SMON discovers that the amount of recovery work is above a certain threshold, it automatically begins parallel rollback by dispersing the work among several parallel processes: process 1 rolls back one transaction, process 2 rolls back a second transaction, and so on. The threshold is the point at which parallel recovery becomes cost-effective, in other words, when parallel recovery takes less time than serial recovery.
One special form of fast-start parallel rollback is intra-transaction recovery. In intra-transaction recovery, a single transaction is divided among several processes. For example, assume 8 transactions require recovery with one parallel process assigned to each transaction. The transactions are all similar in size except for transaction 5, which is quite large. This means it takes longer for one process to roll this transaction back than for the other processes to roll back their transactions.
In this situation, Oracle automatically begins intra-transaction recovery by dispersing transaction 5 among the processes: process 1 takes one part, process 2 takes another part, and so on.
You control the number of processes involved in transaction recovery by setting the parameter FAST_START_PARALLEL_ROLLBACK to one of three values:
FALSE Turns off fast-start parallel rollback.
LOW Specifies that the number of recovery servers may not exceed twice
the value of the CPU_COUNT parameter.
HIGH Specifies that the number of recovery servers may not exceed four
times the value of the CPU_COUNT parameter.
Regards
Raj
"Danisment
Gazi Unal To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
(ubTools)" cc:
<dunal_at_ubTool Subject: Re: production database on aix won't be open, help
s.com>
Sent by:
root_at_fatcity.
com
June 19, 2002
04:27 PM
Please
respond to
ORACLE-L
Hello Rajesh,
You are definitly right. But, as I know Deffered Transaction Rollback feature is intruduced with 7.3.
Also,
there is a good enhancement in 8i which enables SMON to use parallel query
slaves automatically to complete
rollback operation. Current threshold for that is 100 rollback blocks.
Rajesh.Rao_at_jpmchase.com wrote:
> Sorry, but does Oracle not do the rollback in the background, reading
> records from undo$. This is a feature called fast warmstart, introduced
> with 8.0. During an instance recovery, a roll forward is done, and the
> database opened for normal operations. A rollback is done in the
> background.
>
> Raj
>
>
> "Charlie
> Mengler" To: Multiple recipients of
list ORACLE-L <ORACLE-L_at_fatcity.com>
> <charliem_at_mwh cc:
> .com> Subject: Re: production
database on aix won't be open, help
> Sent by:
> root_at_fatcity.
> com
>
>
> June 19, 2002
> 01:28 PM
> Please
> respond to
> ORACLE-L
>
>
>
> It might be that Oracle is simply trying to rollback a _BIG_ uncommitted
> transaction.
> Once in the past I had a similar problem. The fix was amazingly simple. I
> increased
> the size of the TEMP tablespace. I suspect that if you are really,
really,
> really
> patient Oracle eventually will wake from its slumber & begin normal
> operations.
>
> HTH & YMMV,
>
> HAND!
>
> chal_ping wrote:
> >
> > oracle-lHi, grurus:
> > This is a production database 8.1.7.2 on aix 4.3.3, there are
17
> instances running on the same box.
> > I shutdown immediate the database and it hangs.After wait for
one
> hour, i do a shutdown abort. When i startup again, it failed to open the
> database , just hangs at this stage like:
> > Sun Jun 16 09:36:40 2002
> > SMON: enabling cache recovery
> > SMON: enabling tx recovery
> > And the sql*plus window hangs at : database mounted, but never
> showed open.
> > From another shell prompt, i sqlplus internal and query the
> instance, it showed instance open in read write state!
> > But from remote node via listener, client process showed 0134:
> oracle not available.
> > I once met such kind of questions on sun solaris, it is because
> of solaris bug.But never heard of this kind on AIX. Oracle support
suggest
> reboot the server, but as there is 16 other instance on it, it is not the
> solution.
> > Can anyone help?
> > Great thanks.
> >
> > --
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author:
> INET: Rajesh.Rao_at_jpmchase.com
>
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-- Danisment Gazi Unal http://www.ubTools.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: Rajesh.Rao_at_jpmchase.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Wed Jun 19 2002 - 16:15:24 CDT
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