Comments for Oracloid Blog

Comment on v$object_usage empty? by Mariana

Mariana — Wed, 01 Feb 2012 20:12:32 +0000

Just one question. Does the index monitor depend on how the audit trail parameter is set?
Thanks!

Comment on Bind Variable Peeking with no Histograms by zinassswerzz

zinassswerzz — Thu, 05 Jan 2012 07:29:41 +0000

????!!! ? ????? ?????????? ?????, ? ??????? ???????? ? ????????? ???????? ?????? ???? ?? ??????????? (!) ??????? ??? ???????, ?? ????? ??? ?? ????????? ?????????, ? ???? ????????? - ????? ?????????? ?? ??? ????????, ??? ? ??? ???????? ???????????: http://t1234.ru/index-nat.htm !

Comment on HASH GROUP BY can give wrong result in Oracle 10.2 by Change behavior of GROUP BY clause in Oracle 10g. « Application DBA blog

Change behavior of GROUP BY clause in Oracle 10g. « Application DBA blog — Thu, 29 Dec 2011 03:40:49 +0000

[...] Alex had discussed about this behavior at his blog: http://www.oracloid.com/2006/05/hash-group-by-can-give-wrong-result-in-oracle-102/ [...]

Comment on Bind Variable Peeking with no Histograms by Odd Harry Ophaug

Odd Harry Ophaug — Wed, 14 Dec 2011 13:02:27 +0000

@Khurram
Is this really true? According to Oracle Support article “Adaptive Cursor Sharing Overview [ID 740052.1]” the parameter must NOT be set to false for ACS to work:
”
Apart from checking for a valid operator there are also a number of subsequent bind sensitivity checks that need to be performed before it can be marked as bind sensitive, if it fails any of these the cursor will not be marked as bind sensitive and adaptive cursor sharing would not occur.

If any of the following checks fail ECS will be disabled :-
- Extended cursor sharing is disabled
- The query has no binds
- Parallel query is used
- Certain parameters like (”bind peeking”=false) are set
- You are using a /*+ NO_BIND_AWARE */ hint
- Outlines are being used
- It is a recursive query
- The number of binds in a given sql statement are greater than 14
…
Odd Harry

Comment on Bind Variable Peeking with no Histograms by Khurram

Khurram — Wed, 14 Dec 2011 04:24:14 +0000

@Rakesh

I second to you that bind peeking occurs whether you have histogram or not till 10g , ACS for 11g will work only when you disable bind peeking by _optim_peek_user_binds.

Khurram

Comment on v$object_usage empty? by Behroz Bahrami

Behroz Bahrami — Tue, 13 Dec 2011 13:59:52 +0000

Thank you very much for sharing your knowledge as I have been trying to monitor Indexes for a User that we did not have its password and could also reset its password. But by creating V$ALL_OBJECT_USAGE it solved all my problems.

Comment on Oracle 10.2 RMAN Backup on NFS by Malinda Ramadhani

Malinda Ramadhani — Wed, 30 Nov 2011 06:33:45 +0000

Hi Alex,

try this this way to mount

vim /etc/fstab

malinda:/home/oracle/archivelog /home/oracle/archivelog nfs rw,bg,hard,nointr,tcp,vers=3,timeo=300,rsize=32768,wsize=32768,actimeo=0 0 0

Thanks

Comment on VLDB with ASM? by Alex Gorbachev

Alex Gorbachev — Fri, 28 Jan 2011 15:31:55 +0000

@Prakash,

I would like to emphasize that I do not do free consulting on the blog. The blog is created to help readers understand the technology and make right decisions. If your need expert help with a specific production problem we can do a proper analysis and solution as part of Pythian services.

I’m also quite busy these days and usually ignore the requests with “Kindly reply Sonnest by today”.

What you need to do is to understand the impact of the disks you are dropping and whether you still have enough capacity on your normal redundancy disk groups - not only to rebalance the data off the dropped disks but also to survive the failure of one of the disks that are left there. Based on your output, there are normal redundancy diskgroups with only two disks - you won’t be able to recover automatically from a disk failure in these diskgroups.

Comment on Oracle 10.2 RMAN Backup on NFS by Alex Gorbachev

Alex Gorbachev — Fri, 28 Jan 2011 15:00:18 +0000

@Mahesh: Before seeking for a solution, you need to find out what’s the bottleneck of your backup speed. It can be network infrastructure, CPU, low # of spindles, poor RAID choice and bunch of other reasons.

Comment on VLDB with ASM? by Prakash

Prakash — Fri, 28 Jan 2011 14:36:47 +0000

Alex;
Very impressive discussions here, thanks do much. I have a doubt as I’m required to drop 2 of the disks to from 2 diffrent existing normal redundancy diskgroup, in order to create another diskgroups with External rdunndancy. As I have my SAN storage(DS4700) configured with RAID 5, with proper failover capbilities. I’ve posted below my configuration for your perusal, kindly reply by today please.

SQL> ;
1 SELECT
2 NVL(a.name, ‘[CANDIDATE]‘) disk_group_name
3 , b.path disk_file_path
4 , b.name disk_file_name
5 , b.failgroup disk_file_fail_group
6 FROM
7 v$asm_diskgroup a RIGHT OUTER JOIN v$asm_disk b USING (group_number)
8 ORDER BY
9* a.name
SQL> /

DISK_GROUP_NAME DISK_FILE_PATH DISK_FILE_NAME DISK_FILE_FAIL_GROUP
—————————— —————————————- —————————— ——————————
ARCHDG /dev/rhdisk26 ARCHDG_0001 GROUP2
ARCHDG /dev/rhdisk25 ARCHDG_0000 GROUP1
DATADG1 /dev/rhdisk17 DATADG1_0001 GROUP2 — want to take out
DATADG1 /dev/rhdisk16 DATADG1_0000 GROUP1
DATADG1 /dev/rhdisk15 DATADG1_0003 DATADG1_0003 –want to take out
DATADG1 /dev/rhdisk14 DATADG1_0002 DATADG1_0002
DATADG2 /dev/rhdisk27 DATADG2_0002 DATADG2_0002
DATADG2 /dev/rhdisk28 DATADG2_0003 DATADG2_0003 ————– want to take out
DATADG2 /dev/rhdisk19 DATADG2_0001 GROUP2 ———–want to take out
DATADG2 /dev/rhdisk18 DATADG2_0000 GROUP1
INDEXDG /dev/rhdisk22 INDEXDG_0001 GROUP2
INDEXDG /dev/rhdisk21 INDEXDG_0000 GROUP1
TEMPDG /dev/rhdisk24 TEMPDG_0002 TEMPDG_0002— want to take out
TEMPDG /dev/rhdisk11 TEMPDG_0000 TEMPDG_0000
TEMPDG /dev/rhdisk13 TEMPDG_0001 TEMPDG_0001
[CANDIDATE] /dev/rhdisk23
[CANDIDATE] /dev/rhdisk7
[CANDIDATE] /dev/rhdisk8
[CANDIDATE] /dev/rhdisk9
[CANDIDATE] /dev/rhdisk20
[CANDIDATE] /dev/rhdisk12

21 rows selected.

SQL>

I’ve maked the disks , I’m willing to take out. Kindly reply Sonnest by today please.

Regards
Prakash