Sfaturi Oracle / Tips and tricks OracleDBA: octombrie 2012

2012-10-31

HDDs spin continuously and large numbers are needed to meet the aggregate demand of enterprise applications where I/O is the typical bottleneck. A typical high-end HDD supports 144GB of data, 300 IOPS and consumes 20W of power. Adding RAID protection overheads, over 1,000 drives and 20kW are required to support I/O rates of 220,000 IOPS and transfers of 1 GByte/sec. Violin achieves this performance with just 20 flash memory modules (VIMMs) consuming less than 300W of power.

Violin resolves these bottlenecks by reducing latency from 5ms to 200 microseconds, a 25x improvement which significantly increases CPU utilization. This dramatically lowers the need for server memory and CPUs while enabling more efficient virtualization and server consolidation..

PCIe flash cards are faster than SSDs, but are tied to individual servers.

Legacy storage systems featuring SSDs are designed to integrate flash memory within existing HDD enclosures and use software-based RAID controllers. This retrofitting approach results in (delivered) costs of approximately $200 per GByte (RAID-1) and performance in the 10-30K IOPS range with latency typically around 2ms or more. Violin Memory Arrays, on the other hand, can easily integrate into the existing storage network. Costs are now below $20 per GByte and price/performance effectively increases by 500% or more.

2012-10-30

virus politia romana

http://forum.softpedia.com/topic/890694-virus-politia-romana/

how to have identity from sql server in oracle

http://nuijten.blogspot.ro/2012/10/oow-2012-little-things-make-me-happy.html

x int default s.nextval primary key
where s is a sequence

In sqlserver you would have

The following SQL statement defines the "P_Id" column to be an auto-increment primary key field in the "Persons" table:

CREATE TABLE Persons
(
P_Id int PRIMARY KEY IDENTITY,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255)
)

2012-10-29

2012-10-26

how to estimate the size of an index

http://connormcdonald.wordpress.com/2012/05/30/index-size/
explain plan for create index IX on MY_TABLE ( bet_account_num );

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2012-10-25

ORA-20000: Statistics collection failed for all objects in schema

Bug 11808462 - dbms_stats raises ora-20000: statistics collection failed for all objects in database [ID 11808462.8]

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2012-10-23

ASM after SAN upgrade

Alert: After SAN Firmware Upgrade, ASM Diskgroups ( Using ASMLIB) Cannot Be Mounted Due To ORA-15085: ASM disk "" has inconsistent sector size. ID 1500460.1

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2012-10-22

ing in SWISS

2012-10-15

nttexp

ORA-7445 [nttexp] in Alert Log Every 60-Seconds [ID 1491340.1]

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Elvetia simply surprising

Jungfraujoch - on top of the world

2012-10-13

ntcontab.c

Installation of 11.2.0.3 : ntcontab.c:7:23: error: sys/types.h: No such file or directory. The package :glibc-headers already installed. Steps to identify and resolve the error. [ID 1404742.1]

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4031 KGLH0

ORA-04031 Due To Excessive Growth In KGLH0 Heaps [ID 1351675.1]

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2012-10-11

lant

“Când îi vezi cum zâmbesc fericiţi pentru că le-a mai crescut un pic salariul sau le-a mai scăzut un pic dobânda, te prefaci că nu le auzi zăngănitul lanţurilor de la picioare. Şi până la urmă, dacă lor li se pare că pot zburda cu bila de ocnaş legată de picior, cine eşti tu să le spui că nu vor fi liberi niciodată ?"

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