Checkpoint in RAC 2007-12-03 - By Ahmed kdnl
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Thanks Dan for update,
According to my example in the origninal post ,the datafile and control file
will have latest SCN which is T2 ,so it has to apply the redo from T2 since T2
is greater than T1.
Please put some points on it ?
Dan Norris <dannorris@(protected)> wrote:
Checkpoints are instance events, not database events, so in the case
outlined below, instance2 would have to start recovery at the point T1 in
instance1's redo logs and recover from there. As you may know, instance
recovery incurs a certain amount of time where the GRD is frozen and
transactions must wait until it is unfrozen before they can continue. Therefore
, the amount of time required for recovery will affect the behavior of the
database. Moral of the story: take care to ensure that checkpoints happen often
enough to keep that window "short" (as defined by you and your application).
Someone please correct me if I've gone off the path somewhere.
Hope that helps.
Dan
-- -- Original Message ----
From: Ahmed kdnl <sulkdnl@(protected)>
To: oracle-l@(protected)
Sent: Wednesday, November 28, 2007 1:07:01 AM
Subject: Checkpoint in RAC
Hi
Anyone put some points on how checkpoint happening in RAC?
For example intance1 checkpointed at time T1 and instance2 checkpointed at
time T2
Now in case of instance1 failure ,how instanace2 does the recovery of
instance1.
From which checkpoint time, it will read and apply redo,T1 or T2?
Thanks in advance
Syed
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<div>Thanks Dan for update,</div> <div> </div> <div>According to my
example in the origninal post ,the datafile and control file will have
latest SCN which is T2 ,so it has to apply the redo from T2 since T2 is
greater than T1.</div> <div>Please put some points on it ?</div> <div> <
/div> <div><BR><BR><B><I>Dan Norris <dannorris@(protected)></I></B>
wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT:
5px; BORDER-LEFT: #1010ff 2px solid"> <STYLE type=text/css><!-- DIV {margin
:0px;} --></STYLE> <DIV style="FONT-SIZE: 10pt; FONT-FAMILY: arial,helvetica
,sans-serif"> <DIV style="FONT-SIZE: 10pt; FONT-FAMILY: arial,helvetica,sans
-serif">Checkpoints are instance events, not database events, so in the case
outlined below, instance2 would have to start recovery at the point T1 in
instance1's redo logs and recover from there. As you may know, instance
recovery incurs a certain amount of time where the GRD is frozen and
transactions must wait until it is unfrozen before they can continue.
Therefore, the amount of time required for recovery will affect the behavior of
the database. Moral of the story: take care to ensure that checkpoints happen
often enough to keep that window "short" (as defined by you and your
application). <BR><BR>Someone please correct me if I've gone off the path
somewhere.<BR><BR>Hope that helps.<BR><BR>Dan<BR><BR> <DIV style="FONT-SIZE:
12pt; FONT-FAMILY: times new roman,new york,times,serif">-- -- Original
Message ----<BR>From: Ahmed kdnl <sulkdnl@(protected)><BR>To: oracle-l
@(protected)<BR>Sent: Wednesday, November 28, 2007 1:07:01 AM<BR>Subject:
Checkpoint in RAC <BR><BR> <DIV>Hi</DIV> <DIV> </DIV> <DIV>Anyone put
some points on how checkpoint happening in RAC?</DIV> <DIV> </DIV> <DIV
>For example intance1 checkpointed at time T1 and instance2 checkpointed at time
T2</DIV> <DIV>Now in case of instance1 failure ,how instanace2 does the
recovery of instance1.</DIV> <DIV>From which checkpoint time, it will read
and apply redo,T1 or T2?</DIV> <DIV> </DIV> <DIV> </DIV> <DIV
>Thanks in advance</DIV> <DIV>Syed</DIV> <div></div> <HR SIZE=1> Get easy,
one-click access to your favorites. <A href="http://us.rd.yahoo.com/evt=51443/
*http://www.yahoo.com/r/hs" target=_blank rel=nofollow>Make Yahoo! your homepage
.</A> </DIV><BR></DIV></DIV></BLOCKQUOTE><BR><p> 
<hr size=1>Be a better sports nut! Let your teams follow you
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