UKOUG 2008 – Monday

I arrived on the Monday morning for the UKOUG this year, as I figured I’d sleep best at home. The train was packed and it was £46 to stand all the way. And there I was hoping for a nice hour or so to go over the presentation a final time 😦

Oracle 10g Streams: Data Replication – Kirtikumar Deshpande

I’ve always thought streams was more complicated than dataguard. I still think that after this talk, but DBMS_STREAMS_ADM.MAINTAIN procedures seem to make streams a little bit easier to set up.

Streams is a free option with Enterprise Edition. Streams is a solution for data sharing.

3 functional components of streams


Asynchronously captures locally or at downstream database

Extracts changes from the redo stream

changes are formatted as a Logical Change Record (LCR)

DML LCR has row change, object name, owner type of DML, SCN. Most importantly OLD and NEW values for columns.

DDL LCR object name, owner, type of DDL, SCN, DDL text

propagation (staging)

capture publishes messages into an in-memory staging area: streams pool of SGA

Messages remain in staging area until consumed by all subscribers


Apply engine will directly apply the DML or DDL represented by the LCR.

automatic conflict resolution.

Rule based configuration

rules govern capture, staging and apply

Demo of streams being set up with the SCOTT schema using DBMS_STREAMS_ADM.MAINTAIN_TABLES

even less information required when using DBMS_STREAMS_ASM.MAINTAIN_SCHEMA

set _job_queue_interval = 1 (10g recommendation)

streams_pool_size = 200M (minimum set at source and destination)

for wans set SDU

streams uses data pump, dataguard, & advanced queueing.

In chat later in the day, Martin Bach mentioned that streams was still prone to lots of bugs and perhaps was not all that reliable.

Introduction to ASM & ZFS – Me

Well it went ok, but I thought I was a little flat at the beginning. It was a small audience and the stage was also quite a small creaky affair.

Good discussion sprung up amongst the audience around 1/2 way through, though as Doug Burns points out, the question about the SAN was a little bit odd.

Some really nice feedback from Joel Goodman at the end with some tips for improvement.

FAN – Bernhard De Cock Buning

A really small turnout for this, maybe a post lunch thing. Bernhard’s talk was based around quite a few demos, but unfortunately about half way through his laptop gave up the ghost. He stoically carried on, but I think the lack of demos really took the wind out of his sails – what an unfortunate time to have a laptop failure!

Thank Goodness for Dataguard – Rachel Slade

Rachel runs the DBA team at Oxford Brookes, which is just up the road from Nominet, and incidentally where my partner works. Her talk was a good user group talk, in that it consisted of her real world experiences rather than what *should* happen.

Essentially during maintenance/power outages brookes suffered some problems with their storage meaning that had to utilise their dataguard instance. They are really just using dataguard as a “hot” offsite backup, and essentially performed rman backups to recover then rolled forward using the archivelogs found at their DR site.

I personally felt this architecture lacks a little innovation, i.e. Brookes has no potential to failover/switchover to their DR site,  but Rachel was stressing the point of keeping it simple and they have seen a return on their dataguard investment.

The Best Way – Tom Kyte

Tom is such an engaging speaker that the time just flies past when he is on stage. The best bit for me, was the cartoon on questioning authority – always question, question, question – I was just saying that to my partner the other day that this is how one should always be and it’s the attitude I want the kids to have.

Come to think of it, I pretty much constantly here why, why, why at home!


2 thoughts on “UKOUG 2008 – Monday

  1. Streams is not difficult to set up, but its difficult to troubleshoot and there are many different issues that tend to come up.
    If you worked with logical standby, its a similar story.

    I heard you gave a great presentation 🙂

  2. Hi Chen,

    Thanks for reading!

    On streams I’ve heard a few people complain about it being a little bit buggy, I’ve a project coming up that could either be active dataguard, or streams. I’m really keen to go with active dataguard rather than streams – even if I have to wait a bit longer (prefer to go with 11gR2).

    ach, on the talk, definitely came across as nervous to begin with.



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