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Constraints and Indexes

Here is an interesting discussion on Constraints and Indexes.


Oracle PreConfigured Templates

A quick post to list the Oracle PreConfigured Templates :

Oracle VM Templates that can be used for Test/Development *and* Production setup on Oracle VM

Oracle VirtualBox VMs for Developers -- as VirtualBox can be easily installed on desktops


SSDs for Oracle

Gwen Shapira has investigated SSDs and Flash and published her findings as "De-Confusing SSD (for Oracle Databases)".   The post *and* the comments are worth a read.


ROWIDs from an Index

Earlier today there was a question : "can i use rowid as a column in index columns ?"

It's clear that you cannot index the ROWID :

SQL> connect hemant/hemant
SQL> create table obj_list_tbl as select * from dba_objects;

Table created.

SQL> select rowid from obj_list_tbl where object_id between 1001 and 1005;


Grid and RAC Notes

This is a place-holder for miscellaneous notes on 11gR2 Grid and RAC.
09-Nov-11 : Location of Voting disk

If the voting disk exists on ASM you cannot add CFS votedisks. You must replace your ASM voting disk with the CFS votedisks. Apparently, both location types cannot be used concurrently ?

[root@node1 crs]# crsctl query css votedisk
## STATE File Universal Id File Name Disk group

Oracle's Best-Of-Breed Strategy

Mark Hurd talks to IDG Enterprise about Oracle's Best-Of-Breed Strategy.


Tablespace Recovery in a NOARCHIVELOG database

Following up on my previous blog, I show a Tablespace Restore and Recovery for a NOARCHIVELOG mode database.

This is possible only if all the redo is still available in the online redo logs. !
Do not attempt this if the online redo logs have suffered enough switches that the log that was current during backup and the subsequent transaction(s) has been overwritten.
First, I create a new tablespace :

SQL> connect / as sysdba
SQL> archive log list

CTAS in a NOARCHIVELOG database is a NOLOGGING operation

Normally, a CTAS (CREATE TABLE ... AS SELECT ....) operation generates redo and logging. However, if the database is in NOARCHIVELOG mode, Oracle silently converts it to a NOLOGGING operation.

This also means that a CTAS in a Test database (that is NOARCHIVELOG mode) will run faster than a CTAS in a Production database (that is ARCHIVELOG mode) , allowing for differences in server and I/O performance.
Here is a demonstration :
I first create a Tablespace and run a Backup, with the database in NOARCHIVELOG mode :

Index Organized Table(s) -- IOT(s)

Here is a very useful series of write-ups on Index Organized Table(s) by Martin Widlake.

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