Importance of VIP
Real Application Clusters in 10g, however, don’t particularly want you to connect to physical IP address associated with network interface.
Doing so means IP packets are routed to a physical MAC address, so that if that address ever ceases to exist (such as when a server dies), we have to wait for TCP/IP networking protocol itself to work out that packets are undeliverable.
That can take up to 10 minutes, and would mean failover in a RAC can potentially be very slow.
Instead, Oracle wants users to connect to a Virtual IP Address (VIP). That’s an IP address that’s bound to a software-controlled MAC address and since it’s software controlled, the software can arrange for failures to be handled a lot quicker than plain old TCP/IP stack (in seconds, usually).
The VIP for a RAC node is quite often the normal, real IP address plus one so, in my case, that would imply a VIP of 192.168.1.111. I won’t be needing this until it comes time to installing the Oracle software, but it’s good to plan ahead.
Even if check fails you can continue the installation,by configuring vipca seaparately , even if that IP does not exist (no need that you own that ip).
Metadata API (DBMS_METADATA)
Prior to Oracle9i metadata could only be extracted using SQL statements, export utilities and the OCIDescribeAny interface, all of which are limited:
* The SQL approach is limited in that as versions change, so must your scripts.
* Using export with ROWS=N and an import with SHOW=Y will produce the text to allow you to recreate a schema, but it can require considerable editing.
* The OCIDescribeAny interface is limited in the objects it supports.
To solve these issues Oracle9i has introduced the DBMS_METADATA package which can be used to retrieve object definitions as XML or SQL DDL: Read more…
Our preferred v$sqlarea query is to actually report on physical disk I/O per statement execution. Hit ratios are informative but sometimes misleading. Logical I/O is less relevant. If the statement executes 1,000,000 logical I/Os but still only takes less than one-tenth of a second, who cares? It is the total physical I/O that consumes nearly all the time and identifies the potentially incorrect SQL. For example:
Read more…
System Parameters Purpose: Reports all system parameters, including the hidden ones
Read more…
I have seen this issue on number of SAP systems. I will compile a procedure I followed here.
Read more…
undo_retention parameter will not guarantee a RETENTION unless you define a RETENTION GUARANTEE CLAUSE on tablespace level
Read more…
1> What resource is currently in high demand?
select active_session_history.event
, sum ( active_session_history.wait_time + active_session_history.time_waited ) ttl_wait_time
from v$active_session_history active_session_history
where active_session_history.sample_time between
sysdate – 60 / 2880
and sysdate group by active_session_history.event
order by 2
Read more…
The easiest approach is to use an Oracle utldtree.sql script. This will be located in the %ORACLE_HOME%\rdbms\admin\ directory.
Read more…
Please chnage “like” string for filtering results for a specific SQL statement.
set linesize 150;
set pagesize 1000;
BREAK ON hash_value SKIP 1;
spool 1_sql.lst;
select hash_value,to_char(snap_time,’DD-MON-YY HH24:MI:SS’),snap_id,piece, sql_text from STATS$SQLTEXT a, stats$snapshot b where hash_value in (
select hash_value
from STATS$SQLTEXT where sql_text like ‘SELECT%VBELN%KUNNR%ZZCURRENT_OWNER%VBKA%’)
and b.snap_id=a.last_snap_id
order by snap_time,hash_value,piece;
spool off;
Read more…
Long running operations such as imports and batch processes sometimes fail because the server is unable to allocate more extents for an object. This may be because the object has reached max_extents or there isn’t sufficient room in the tablespace for the object to expand. In previous releases the operation would have to be rerun, possible with some manual cleanup necessary. In Oracle9i operations that would fail due to space allocation problems can be suspended and restarted once the problem is fixed.
* Resumable Mode
* Timeout Period
* AFTER SUSPEND Trigger
* Views
* DBMS_RESUMABLE Package
* Restrictions
Read more…
Oracle trace events are useful for debugging the Oracle database server.
The following two examples are simply to demonstrate syntax. Refer to later notes on this page for an explanation of what these particular events do.
Read more…
2 Oracle databases – A & B. Server A is available and need to be replicated on server B. We will use rman to backup datafiles including control file and archive logs.
Read more…
To setup rda collection at cluster
Read more…
Physical WRITES from the time Instance Started
Read more…
Case 1 : EM console is working at Node 1. Node 1 is shutdown , services failover to Node 2 but oemctl doesn’t failover to Node 2
Read more…
Oracle support referred me to Metalink Note 139642.1 to downgrade Enterprise Edition (EE) to the
Standard Edition (SE). They said we can not just downgrade the software, this will not get rid of EE. I MUST export / import, in order to go from EE to SE.
Read more…
For more details visit metalink note 259301.1 & download showcrs shell script
[oracle@ora02 ~]$ crs_stat -t
Name Type Target State Host
————————————————————
ora….SM1.asm application ONLINE ONLINE ora01
ora….01.lsnr application ONLINE ONLINE ora01
ora….a01.gsd application ONLINE UNKNOWN ora01
ora….a01.ons application ONLINE UNKNOWN ora01
ora….a01.vip application ONLINE ONLINE ora01
ora….SM2.asm application ONLINE ONLINE ora02
ora….02.lsnr application ONLINE ONLINE ora02
ora….a02.gsd application ONLINE UNKNOWN ora02
ora….a02.ons application ONLINE UNKNOWN ora02
ora….a02.vip application ONLINE ONLINE ora02
ora.prod.db application ONLINE ONLINE ora01
ora….prod.cs application OFFLINE OFFLINE
ora….od1.srv application ONLINE UNKNOWN ora01
ora….od2.srv application ONLINE UNKNOWN ora02
ora….d1.inst application ONLINE ONLINE ora01
ora….d2.inst application ONLINE ONLINE ora02
Read more…
Tweet
