Amardeep Sidhu's Tech blog

Just a quick note about change in the way the compute nodes are patched starting from version 11.2.3.1.1. For earlier versions Oracle provided the minimal pack for patching the compute nodes. Starting with version 11.2.3.1.1 Oracle has discontinued the minimal pack and the updates to compute nodes are done via Unbreakable Linux Network (ULN). Now there are three ways to update the compute nodes: You have internet access on the Compute nodes. In this case you can download patch 13741363, complete the one time setup and start the update. ...

There was an interesting issue at one of the customer sites. Few tables in the database were altered and the dependent objects became invalid. But the attempts to compile the objects using utlrp.sql or manually were failing. In all the cases it was giving the same error: SQL> alter function SCOTT.SOME_FUNCTION compile; alter function SCOTT.SOME_FUNCTION compile * ERROR at line 1: ORA-00604: error occurred at recursive SQL level 1 ORA-01422: exact fetch returns more than requested number of rows ORA-06512: at line 27 SQL> At first look it sounded like some issue with the dictionary as the error in case of every object (be it a view, function or package) was the same. ...

Sometimes you may need to run GoldenGate on some different machine than the one that hosts the database. It is very much possible but some kind of restrictions apply. First is that the Endian order of both the systems should be same and the second is the bit width has to be same. For example it is not possible to run GoldenGate on a 32 bit system to read from a database that runs on some 64 bit platform. Assuming that the environemnt satisfies the above two conditions; we can use the LOGSOURCE option of TRANSLOGOPTIONS to achieve this. ...

Just a quick note/post about the significance of COMPRESS and TCPBUFSIZE parameter in performance of a GoldenGate Extract Pump process. COMPRESS helps in compressing the outgoing blocks hence helping in better utilization of the bandwidth from source to target. GG is going to uncompress the blocks before writing them to the remote trail file on the target. Compression ratios of 4:1 or better can be achieved. Of course, use of COMPRESS may result in increased CPU usage on both the sides. ...

Hybrid Columnar Compression (HCC) is a new awesome feature in Exadata that helps in saving a lot of storage space in your environment. This whitepaper on Oracle website explains this feature in detail. Also Uwe Hesse has an excellent how to use all this post on his blog. You can see the compression levels one can achive by making use of HCC. It is very simple to use feature but one needs to be aware of few things before using HCC extensively as otherwise all your storage calculations may go weird. Here are few of the things to keep in mind: ...

The last post was just like that. It was this GoldenGate issue that woke me up from the deep sleep to do a post after a long time :P . Well it was a simple schema to schema replication setup using GoldenGate. We were using the SCN method (Metalink Doc ID 1276058.1 & 1347191.1) to do the intial load so that there is no overlvapping of transactions and the replicat runs with minimum issues. Even after following this method, the replicat was hitting ...

Came across this small oddity that documentation of 10.2 and 11.2 states that expdp by default takes consistent image of the database. But actually it is not so. You need to use flashback_scn/flashback_time for that. Metalink doc 377218.1 explains the scenario. Comments Comment by Chris Fischer on 2011-11-04 19:47:12 +0530 I’ve been warning my customers about this for years. “Shut down all db access before taking a schema or full expdp!” ...

It was a 10g (10.2.0.5 on HP-UX 11.23 RISC) database which was recently upgraded from 9.2.0.8. The CPU and memory utilization was going really high. After tuning few of the queries coming in top, CPU usage was coming within accetable limits but the memory usage was still high. There was a total of 16 GB of RAM on the server and the usage was above 90%, constantly. One of the reasons behind high usage was increase in the SGA size. It was increased from 2.5 GB (in 9i) to around 5 GB (in 10g). Another major chunk was being eaten by OS buffer cache. While looking at the memory usage with kmeminfo:[bash]Buffer cache = 1048448 4.0g 25% details with -bufcache[/bash] ...

Very simple issue but took some amount of time in troubleshooting so thought about posting it here. May be it proves to be useful for someone. Scenario was: Oracle is installed from “oracle” user and all runs well. There is a new OS user “test1” that also needs to use sqlplus. So granted the necessary permissions on ORACLE_HOME to test1. Tried to connect sqlplus scott/tiger@DB and yes it works. But while trying sqlplus scott/tiger it throws: ...

Some time back, I was at a client where the customer complained that no one was able to log in to the database. It was Oracle 10.2.0.4 running on HP-Ux. I logged in to the database and checked the wait events: [sql]SQL> @wait EVENT COUNT(*) ---————————————————————- ———- wait for possible quiesce finish 1 Streams AQ: qmn coordinator idle wait 1 Streams AQ: qmn slave idle wait 1 Streams AQ: waiting for time management or cleanup tasks 1 SQL*Net message to client 1 smon timer 1 pmon timer 1 jobq slave wait 4 rdbms ipc message 11 SQL*Net message from client 27 resmgr:become active 322 ...