1.Flashback query Depend on:content in undo tablespace 1.1Base syntax: 1: SELECT ... FROM ... AS OF TIMESTAMP TO_TIMESTAMP('...','yyyy-mm-dd hh24:mi:ss')
Oracle Import and Export
Chapter:SQL*Loader Lab1.Import text file to database assume text file is like this: 1: 60,CONSULTING,TORONTO
SQL explain plan and AWR
DBMS generates an explain plan for each SQL commands.What does explain plan work for? As is known,it can use ‘full table scan’ or ‘index’ access destinate data.Which method does DBMS choose?What is t
1.STANDARD AUDITING(FOCUS ON DBA)Standard auditing is enabled by default after installation.It records login,startup,shutdown information about database instance only.If I intend to enable auditing o
Manage Undo Tablespace
Every session has exclusive transaction which has specified undo segment.When you have performed some SQL operations,you can refer v$transaction to find some information about the related transaction.
Data Concurrent Experiment(Lock conflict)
There's a stage as below: There are 2 users ngreenberg and smavris,operating at the same time.Smavris' session seems stuck.All Commands are as below (in the order of time):ngreenberg)SQL> show user
Why does there exist DB_UNKNOWN directory on ASM disk?
Today I found a glitch about my database instance.When I browsed my files on ASM disks,I found this file,which path was '+DATA/DB_UNKNOWN/parameterfile/spfile.278.186024535'.I used 'ls -al' to see whi
How ASM instance reads initiator parameter file on ASM disk when startup?
As is known,ASM instance need to read initiator parameter file when startup.However,the diskgroups are not mounted at that time.How does ASM instance read it?Oracle ASM uses registry to locate initiat
Using Raw Devices in Oracle ASM
Q:When will you use raw devices in ASM?A: 1.There's no approximate asmlib for kernel of your host 2.You wanna promote I/O performance of database under your estimation compar