Year: 2016

Database Links in Oracle

A database link is a schema object in one database that enables you to access objects on another database.

SQL> desc dba_db_links
 Nombre                                                                                     ¨Nulo?   Tipo
 —————————————————————————————— ——– ————————————————————-
 OWNER                                                                                      NOT NULL VARCHAR2(30)
 DB_LINK                                                                                    NOT NULL VARCHAR2(128)
 USERNAME                                                                                            VARCHAR2(30)
 HOST                                                                                                VARCHAR2(2000)
 CREATED                                                                                    NOT NULL DATE

Use the below query to find the db links available for a database:


set lines 152
col owner for a15
col db_link for a30
col username for a15
col host for a30

select owner,db_link,username,host,CREATED
from dba_db_links;

spool db_link_test.sql

select ‘select count(*) from tab@’||db_link||’;’
from dba_db_links;

spool off

spool db_link_output.log

@db_link_test.sql

spool off

=================


How to Test if a DB link is working fine?

select ‘ connect ‘||owner||’/’||owner||’1’||chr(10)||
‘select count(*) from tab@’||db_link||’;’
from dba_db_links;

select distinct owner
from dba_db_links;

R12.2 Filesystem Layout

  • File System 1 (FS1)–Stores a complete copy of all  Applications and Middle Tier code
  • File System 2 (FS2)–Stores a complete copy of all Applications and Middle Tier code 
  • File System Non-Editioned (FS_ NE)–Stores data that is written or read from the file system,Report Outputs,Log Files etc.

FS1 and FS2 Rotate Run and Patch Designation

How to Put Concurrent Requests in Hold Status?

During some scheduled maintenance activities, oracle apps database administrator would require to keep the Pending Jobs on Hold before bounce and release them after the scheduled activity.
This process help to bring down Concurrent Manager quickly and the pending jobs are preserved for running after the maintenance is complete.

1) Create table apps.conc_req_on_hold as select * from fnd_Concurrent_requests where PHASE_CODE=’P’ and hold_flag=’N’;
2) select count(*) from apps.conc_req_on_hold
3) update fnd_Concurrent_requests set hold_flag=’Y’ where PHASE_CODE=’P’ and hold_flag=’N’ and request_id in (select request_id from apps.conc_req_on_hold);

NOTE: You have to commit if select & update are same number of records. Otherwise rollback and try again till the numbers are same

4) Commit;

To Release hold on Concurrent Requests patching, run the below sql :

5) update fnd_Concurrent_requests set hold_flag=’N’ where request_id in (select request_id from apps.conc_req_on_hold);

6)Commit the changes

 commit;


ONE NODE RAC Features in Oracle Database 11g Edition

•Available
from 11gr2, Express Edition.
•High
availability feature.
•Provides
Cold failover Solution.
•Automates
instance relocation incase of instance failure or fault in the first node.
•Facilitates
rolling upgrade for single instance database.
•Live
migration of instances across servers.

•Uses omotion
utility to migrate the instance.

Query to Find Free Space in a Tablespace

undefine tbsp
set lines 152
set echo off

col tablespace_name for a20
select utbs.tablespace_name,
round(utbs.mb) “Allocated Used/Unused MB”,
round(Ftbs.mb) “Allocated_Free MB”,
round((100/utbs.mb)*Ftbs.mb) “%Allocated_Free MB”,
decode(sign(round(utbs.Maxmb-utbs.mb)),-1,0,round(utbs.Maxmb-utbs.mb)) “Space_AutoExtensible MB”,
Ftbs.MaxBytes “MaxChunk MB”
from
(select ddf.tablespace_name,sum(ddf.bytes)/1048576 MB,sum(ddf.maxbytes)/1048576 MaxMB
from dba_data_files ddf
group by ddf.tablespace_name) Utbs,
(select dfs.tablespace_name,sum(dfs.bytes)/1048576 MB,max(dfs.bytes)/1048576 MaxBytes
from dba_free_space dfs
group by dfs.tablespace_name) Ftbs
where utbs.tablespace_name=ftbs.tablespace_name
and utbs.tablespace_name like ‘%&&TBSP%’
order by round(Ftbs.mb)
/