Oracle Virtualization and Cloud Consulting
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High value IT jobs moving back to USA.

Not very good news for skilled people in India? TOI: IT firms to suffer as angry America wants its jobs back

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Reading an AWR -- 2

I have extracted this from an AWR report :

      

Elapsed Elapsed Time
Time (s) Executions per Exec (s) %Total %CPU %IO SQL Id
---------------- -------------- ------------- ------ ------ ------ -------------
277.8 1 277.85 97.6 14.9 59.4 8madvr3cvp929
Module: SQL*Plus
select count(*), sum(sale_qty), sum(discount_rate) from very_large_fact_table


CPU CPU per Elapsed

Oracle 11g RAC Essentials

PACKT Publishing had invited me to review the new 11g RAC book "Oracle 11g R1/R2 Real Application Clusters Essentials". This book, published in May 2011, is an update on the earlier book "Oracle 11g R1/R2 Real Application Clusters Handbook" published in June 2010.

More on COUNT()s -- 2

Continuing with my previous posts "Running a COUNT(Column) versus COUNT(*)" and"More on COUNT()s", I now go on to demonstrate some more "twists" :


SQL> drop table COUNT_ROWS_TBL ;

Table dropped.

SQL> create table COUNT_ROWS_TBL (Column_1 number, Column_2 number, Column_3 varchar2(100)) ;

Table created.

SQL> insert into COUNT_ROWS_TBL

More on COUNT()s

As a followup to my previous post "Running a COUNT(column) versus COUNT(*)", here's a demo of :
a. COUNT(column)
b. COUNT(constant)
c. COUNT(*)
d. COUNT(*) done via an Index

SQL> -- Create a test table with 3 columns
SQL> -- The first column happens to have a NULL value for every 10th row
SQL> -- Column_2 contains numbers, all greater than 0
SQL> -- so a query for "WHERE Column_2 > 0" retrieves ALL the rows

Data Quality Issues cannot always be addressed by programming

Here's an example of a data quality issue that SQL , PLSQL, Oracle Text etc cannot resolve for you :

http://forums.oracle.com/forums/thread.jspa?threadID=2259111&tstart=0

See my comments in the thread.
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Running a COUNT(column) versus COUNT(*)

Just a quick post about the recurring myths about COUNT operations in Oracle.
See the discussion in this forums thread.
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ENABLE ROW MOVEMENT with MSSM

As I demonstrated in my previous blog post "ENABLE ROW MOVEMENT" the ALTER TABLE ... ENABLE ROW MOVEMENT is not just for supporting the ALTER TABLE ... SHRINK SPACE.

Furthermore, unlike ALTER TABLE ... SHRINK SPACE which requires that the Table be created in a Tablespace with Segment Space Management AUTO ("ASSM"), ENABLE ROW MOVEMENT can be done for a table in a Segment Space Management MANUAL ("MSSM") Tablespace as well.


SQL> create tablespace MSSM

Virtathon Sessions Schedule

The Sessions Schedule for Virtathon has been published.

View it here.

(note : The published session times are US EDT (GMT -4))

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