Re: oracle database-startup time
From: joel garry <joel-garry_at_home.com>
Date: Fri, 26 Nov 2010 10:03:15 -0800 (PST)
Message-ID: <fcf3d231-b40b-4ea1-a1d4-1c524854e7e7_at_r21g2000pri.googlegroups.com>
On Nov 23, 2:32 am, Noons <wizofo..._at_yahoo.com.au> wrote:
> alex123 wrote,on my timestamp of 23/11/2010 5:36 AM:
>
> >>> I wanted to know what oracle database startup time depends on? Does
> >>> size of database matter or it is constant on the same machine?
>
> >> What do you mean by "database startup" time?
>
> > Time of executing command 'startup' (when database is shut down)
>
> If you have a very large SGA (tens of Gigabytes) and you are not using hugepages
> - or its equivalent in your OS - then it will take some time to startup, no
> matter what. In our Power6 IBm it takes 90 seconds to allocate all page tables
> for an SGA of 35GB. If I use hugepages, it takes 2 seconds. That's how much
> difference it makes.
>
> If the startup follows a shutdown abort then it will also be slow, depending on
> how many redo log files you have and how busy with changes the database was at
> the time of the shutdown. Other than shutdown abort, the size of redo logs has
> almost no impact on startup time. We use 1GB redos and it makes no difference
> whatsoever.
>
> Size of database is mostly immaterial. Other than size of undo and redos in the
> case above.
Date: Fri, 26 Nov 2010 10:03:15 -0800 (PST)
Message-ID: <fcf3d231-b40b-4ea1-a1d4-1c524854e7e7_at_r21g2000pri.googlegroups.com>
On Nov 23, 2:32 am, Noons <wizofo..._at_yahoo.com.au> wrote:
> alex123 wrote,on my timestamp of 23/11/2010 5:36 AM:
>
> >>> I wanted to know what oracle database startup time depends on? Does
> >>> size of database matter or it is constant on the same machine?
>
> >> What do you mean by "database startup" time?
>
> > Time of executing command 'startup' (when database is shut down)
>
> If you have a very large SGA (tens of Gigabytes) and you are not using hugepages
> - or its equivalent in your OS - then it will take some time to startup, no
> matter what. In our Power6 IBm it takes 90 seconds to allocate all page tables
> for an SGA of 35GB. If I use hugepages, it takes 2 seconds. That's how much
> difference it makes.
>
> If the startup follows a shutdown abort then it will also be slow, depending on
> how many redo log files you have and how busy with changes the database was at
> the time of the shutdown. Other than shutdown abort, the size of redo logs has
> almost no impact on startup time. We use 1GB redos and it makes no difference
> whatsoever.
>
> Size of database is mostly immaterial. Other than size of undo and redos in the
> case above.
Missed the OP, but perhaps googling DBA_HIST_INSTANCE_RECOVERY may come up with some explanations of the various settings that may be used to limit startup time.
jg
-- _at_home.com is bogus. http://www.cio.com/article/639363/Oracle_Awarded_1.3_Billion_in_SAP_LawsuitReceived on Fri Nov 26 2010 - 12:03:15 CST