Re: snapshot data: can oracle somehow compress it?

I can't think of any clever design tricks that would help. However Oracle 9
allows for data segment compression
which can reduce storage dramatically
by keeping (loosely speaking) a single
copy of repeated column items on a
block by block basis.

This is only appropriate for readonly
data, though, so if you can set up a
system where your data set is partitioned and older partitions can be made readonly, then you could find that it gives you a big data storage benefit, with no apparent
structural complexity, but an extra cost in CPU to unpack the data when required.

--
Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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<pete_at_mynix.org> wrote in message
news:1049841141.76713.0_at_despina.uk.clara.net...


> We have an app that stores daily snapshots of data, such as:

>

> day1, a1, b1, c1

> day2, a1, b1, c1

> day3, a1, b1, c2

> day4, a1, b1, c2

>

> etc

>

> In general, much of the data won't change between two days.

Therefore


> storing full snapshots is extremely wasteful w.r.t. diskspace.

>

> I was wondering/thinking that Oracle should be able to store such

> snapshots more intelligently while creating the illusion of daily

full


> snapshots:

>

> In the example above it might be physically stored as:

>

> from-day1, to-day2, a1, b1, c1

> from-day3, to-day4, a1, b1, c2

>

> i.e. as long as no column except for the date column changes, all

> dates could be captured in a single physical record with a from/to

> range for the date.

>

> Currently we do such things manually, but that is quite tedious and

> prone to errors.

>

> Is there some feature or option in Oracle to do this for us?

>

>

> --

> Peter Mutsaers, Dübendorf, Switzerland.