RE: A VLDB contest

From: Luca Canali <Luca.Canali_at_cern.ch>
Date: Wed, 30 Aug 2006 09:29:26 +0200
Message-ID: <F9411E3A291FB5449991ED7E624D27F4017E4574@cernxchg20.cern.ch>

Hi Kevin,  

From my largest DB:  

POOL         NAME                            BYTES
------------ -------------------------- ----------

shared pool ASM extent pointer array 185352360

I imagine this memory is strictly related to X$KFFXP, correct me if I am wrong.

Thanks,
L.

PS:
From the same DB:

SQL> select sum(TOTAL_MB) from v$asm_diskgroup_stat;

SUM(TOTAL_MB)

---

     24398576

Does this mean that Oracle is using on average 9 bytes per extent ?

---

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Kevin Closson Sent: Wednesday, August 30, 2006 1:39 AM To: Bobak, Mark; ORACLE-L
Subject: RE: A VLDB contest

Right, the ASM instance gives the pointer array info to the consumer instances where it is cached in the shared pool.  

I've not seen one iota of discussion on this list about how Oracle maps a data block to an extent within an ASM diskgroup. Must not be an interesting topic?  

It is indeed using these pointers. Such mapping is never free. Volume managers have always had to do that--but have always stored such mappings in kernel memory. No FUD intended here. I just wanted to get people curious about the topic.    

---

	From: Bobak, Mark [mailto:Mark.Bobak_at_il.proquest.com] 
	Sent: Tuesday, August 29, 2006 4:30 PM
	To: kevinc_at_polyserve.com; ORACLE-L
	Subject: RE: A VLDB contest
	
	
	I don't have an 'ASM extent pointer array' at all in my ASM

instance....          

	  1  select * from v$sgastat
	  2  where name like '%ASM%'
	  3* order by bytes
	SQL> /
	 
	POOL         NAME                            BYTES
	------------ -------------------------- ----------
	shared pool  ASM rollback operations          2592
	shared pool  ASM map operations               3360
	shared pool  ASM db client                   11840
	shared pool  ASM buffer object               37288
	shared pool  ASM file                        75328
	
	 
	 
	In my database instance that relies on ASM, however.....
	 
	 
	  1   select * from v$sgastat
	  2   where name like '%ASM%'
	  3* order by bytes
	SQL> /
	 
	POOL         NAME                            BYTES
	------------ -------------------------- ----------
	shared pool  ASM rollback operations          2592
	shared pool  ASM map operations              16856
	shared pool  ASM file                        19200
	large pool   ASM map operations hashta      393216
	shared pool  ASM extent pointer array      9527624
	
	 
	-Mark
		 

	-- 
	Mark J. Bobak 
	Senior Oracle Architect 
	ProQuest Information & Learning 

	Ours is the age that is proud of machines that can think and

suspicious of men who try to. --H. Mumford Jones, 1892-1980          

---

        From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Kevin Closson

	Sent: Tuesday, August 29, 2006 7:24 PM
	To: ORACLE-L
	Subject: A VLDB contest
	
	


	Does anyone actually have ASM "put to the test" as they say?
Anyone 
	have huge ASM extent pointer array areas within their shared
pool? Anyone 
	have "ORA-4031-creeping syndrome" ? 

	For instance: 
	         select * from v$sgastat; 
	POOL         NAME                            BYTES 
	------------ -------------------------- ---------- 
	 shared pool ASM extent pointer array 287097144 

	Anyone see 1GB or more? 



	Kevin Closson 
	Chief Architect, Oracle Database Solutions 
	PolyServe, Inc 
	kevinc_at_polyserve.com 
	http://www.polyserve.com/oracle_consolidation.php
<http://www.polyserve.com/oracle_consolidation.php>  
	http://www.polyserve.com/oracle_rac_clusters.php

<http://www.polyserve.com/oracle_rac_clusters.php>

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Received on Wed Aug 30 2006 - 02:29:26 CDT