Title: RE: Oracle Compress Option
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we have 2 gbit private interconnects of which only one is used at any
given time. Everyone else talks to the dbs using public network. Both are
active/active. On one instance luckily we have application partitioning one side
manages the feeds that come from every foot/bast/basketball, hockey and scores
of other games and processes them and sends it out to customers. Another side
takes this data plus people sitting to make corrections if any before it is fed
to video generators and goes on espn network broadcast. So it works
fine.
Other instances are legacy ... the active/active is more like a HA
configuration, lots of people connected on either side all the time lots of DML
activity going around all the time. We see more of a GC traffic ... but we are
experimenting with _fairness_threshold parameter to see if that will help. As
for performance issues, we encounter lots of BBW but unfortunately that is due
to business logic and can't be easily changed.
Otherwise we do fine.
Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot
com
All Views expressed in this email
are strictly personal.
QOTD: Any clod
can have facts, having an opinion is an art !
Hm, interesting...
How does your active-active config work, do you
have write activity on all nodes?
I'd be interested in any performance issues you
had or currently have...
Have you partitioned your application or data
usage somehow?
What kind of interconnect you're
using?
Tanel.
----- Original Message -----
Sent: Thursday, September 25, 2003 4:49
PM
Subject: RE: Oracle Compress
Option
Waleed, I get your point ...
We have 6 RAC instances that run active-active ... and compared to
availability requirements, we (incl management) decided that disk is
cheap.
I guess it is relative ...
Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot
com
All Views expressed in this
email are strictly personal.
QOTD: Any clod can have facts, having an opinion is an art !
Disk is not
cheap if you pay for high availability configuration. I compress
historical data on daily basis and was able to save 70 percent of the disk
space. Imagine the amount of savings for five TB.
Two major
issues:
1) Oracle
says updates will be slow on compressed tables, but I say don't even try
to update a compressed table, uncompress first otherwise you will end up
with a segment that is not good at all for scattered
reads.
2) You can
not add columns to the table when it's compressed, so if you compressed a
big table and need a new column you need to recreate the table without
compression. So adding many extra columns before compression is a good
idea.
It's mainly
good for data warehouses applications.
Regards,
Waleed
I think 9202 doesn't like to export compressed tables in
direct mode ... so watch out for that ... I implemented, tested and next
day reverted back to regular tables due to this export issue. Disk is
cheap.
A BAARF party member wannabe !!
Raj
--------------------------------------------------------------------------------
Rajendra dot Jamadagni at nospamespn dot com
All Views expressed in this email are strictly
personal.
QOTD: Any clod can have facts, having
an opinion is an art !
-----Original Message-----
From:
Mogens Nørgaard [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, September 24, 2003 10:05 PM
To: Multiple recipients of list ORACLE-L
Subject: Re: Oracle Compress Option
"Compress to impress?" by Julian Dyke is a good
presentation on this
topic (see for instance http://www.ukoug.org/calendar/jan03/jan30ab.htm).
I do have the article - 202 K with no compression, 147 K
with
compression :).
Let me know if you're interested, and I'll email it
directly to you.
Mogens
[EMAIL PROTECTED] wrote:
>Does anybody has any experience with Oracle 9I
compression option. I did some test on 9202 with a table of more 14
million rows. Table has total 7 indexes. Surprising both table and
indexes are using more space after compression. Before compression space
used is 13064MB and after compression 13184MB. In both the cases I did
export from source table and stored in two different tablespaces. Any
insight on that and any disadvantages of using that.
>
>Thanks
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