| Need help on resizing log buffer [message #167401] |
Wed, 12 April 2006 17:13  |
dbawannabe
Messages: 3
Registered: April 2006
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Junior Member |
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We have a database(Oracle 10g Release2) that has a log_buffer of 15M. I want to resize this to 5M. I used alter system to set the new value for the log buffer. I re-started the database. I queried the log_buffer size using show parameters command, the log_buffer is still 15M! Although the spfile is showing 5M. I even created a pfile from the spfile (made sure that the log_buffer parameter is set to 5M) and restart the database using the pfile. It still didn't work! What's going on? Any help is highly appreciated. Thanks!
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| Re: Need help on resizing log buffer [message #167409 is a reply to message #167405] |
Wed, 12 April 2006 18:42  |
dbawannabe
Messages: 3
Registered: April 2006
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Junior Member |
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We we're wondering about where that 15M came from too. We just noticed that the log buffer wait times are huge and when we checked the log_buffer size, it's 15M. Anyway, the issue here is not being able to resize the log_buffer. Yes, I know that 10g uses spfile that's why that's the first thing that I changed:
alter system set log_buffer=5242880 scope=spfile;
System was altered successfully. I then shutdown the database and start it again.
On sqlplus and Enterprise Manager, log_buffer is showing 15M. I opened spfile from the Enterprise Manager, log_buffer is changed to 5M. So, the spfile is updated but it didn't apply to memory.
So, I thought maybe it's not reading the spfile. I then created a pfile(init.ora) from the spfile and made sure that log_buffer in the init.ora is changed to 5M. I shutdown the database again and then start it using the init.ora file. I still got the same result, log_buffer is still 15M.
[Updated on: Wed, 12 April 2006 19:03] Report message to a moderator |
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| Re: Need help on resizing log buffer [message #167503 is a reply to message #167409] |
Thu, 13 April 2006 07:09 |
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Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille
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Senior Member
Account Moderator |
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quoting documentation:
LOG_BUFFER
Property Description
-------------------------------------------------------------------
Parameter type Integer
Default value 512 KB or 128 KB * CPU_COUNT, whichever is greater
Modifiable No
Range_of_values Operating system-dependent
Basic No
Long story short, LOG_BUFFER is no longer modifiable and is dependent on hidden parameter _ksmg_granule_size.
There are several related bugs reported on this. Please check metalink. One of the notable bug is a documentation error stating the default value calculation (as shown above). Parameter _ksmg_granule_size plays a major role here.
[Updated on: Thu, 13 April 2006 07:15] Report message to a moderator |
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