Tuesday 28 October 2008

Cloud computing

These two buzz words "cloud computing" have been in my attention lately and I really wanted to find out what they stand for. I got a classic and short definition from Wikipedia:

"Cloud computing is Internet-based ("cloud") development and use of computer technology ("computing"). "
see full definition....

It seems like it is time for the internet to prove what it stands for, the ultimate computer!?

Yes, from the look of things, all of the applications and databases of humankind are going to be on the internet. At the office we will not have "server rooms" any more, but just PCs with Internet browsers. Developers, will be the only kind of IT people that will stay back in the office, they will sit very near to the boss together with Business Analysts and IT Managers. Modern day developers of the future will be using the browser, and rapidly building applications, maybe with "declarative programming". Is it already hapenning? If you look at the business model of companies like Salesforce where they market concepts like "No Software!" and Software as Service (SaaS) and Oracle's hosted rapid application development environment called Oracle Apex one can easily start seeing The Clouds gathering in the sky. How about the Greenplum the Mega-Giga Titanic Datawarehouse for everyone on the Internet. A datawarehouse internet appliance where everyone can put their datawarehouse and access it from anywhere on the earth on a browser and do analysis. No Servers, No hardware, No Software just a login to a workspace on the internet and that's it. Everything you need, tools, spreadsheets will be there on the internet wating for you.

I wonder what will happen to all those other IT guys, SysAdmins, DBAs. Will they lock them up in huge data centres somewhere in the countryside? Will they be needed at all?

Tom Kyte an Oracle Expert was asked a smilar question on his website and here is Thomas Kyte's comment on Cloud Computing.

Or is it going to be as Tom Kyte says that with 'Cloud Computing', databases will just get larger and larger.

Monday 27 October 2008

Monitor the time an RMAN backup takes

To see what RMAN is doing now, and see what SID is doing what sort of work, and how much it has got left to do, use the following SQL. This script is good when you are trying to see how much work an RMAN Channels have got left to do. It is good to watch with the RMAN backup script log (tail -f) as the backup is hapenning. For both scripts you have to lonig as SYSDBA on the instance where the BACKUP
is or RESTORE hapenning.

SELECT sid, 
       ( sofar / totalwork ) * 100 pct_done 
FROM   v$session_longops 
WHERE  totalwork > sofar 
       AND opname NOT LIKE '%aggregate%' 
       AND opname LIKE 'RMAN%' 


---------- --------- ---------- ---------- ----------
       100 27-OCT-08    1554952    1364978 87.7826454

To watch the success or failure of an RMAN job in the past, or even when it is hapenning, you can use the dynamic v$ view v$rman_status. The following query will show you a history of your BACKUP and RESTORE operations. By changing the where start_time > sysdate -1 clause you control how much in the past you want to look at. I am using this on Oracle 10g, I don't know if it is available on Oracle 9i and before.

SELECT To_char(start_time, 'dd-mon-yyyy@hh24:mi:ss') "Date", 
FROM   v$rman_status vs 
WHERE  start_time > SYSDATE - 1 
ORDER  BY start_time 


Date                 STATUS                  OPERATION                         MBYTES_PROCESSED
-------------------- ----------------------- --------------------------------- ----------------
27-oct-2008@11:40:11 FAILED                  RMAN                                             0
27-oct-2008@11:40:29 COMPLETED               BACKUP                                       11812
27-oct-2008@12:06:30 COMPLETED               BACKUP                                       23112
27-oct-2008@12:41:45 COMPLETED               BACKUP                                         160
27-oct-2008@12:42:28 FAILED                  CONTROL FILE AUTOBACKUP                          0
27-oct-2008@17:24:28 RUNNING                 RMAN                                             0
27-oct-2008@17:24:43 COMPLETED               DELETE                                           0
27-oct-2008@17:24:51 COMPLETED               CATALOG                                          0
27-oct-2008@17:25:16 RUNNING                 RESTORE                                  22082.875