Re: tablespace calculating

Small correction

As Mark and Dale's posts state you have 29 not 30 char columns and their length is 20 not 30 bytes.

This brings the row size down by 40% or so. I would still maintain the broad approach outlined below of best guessing and then adjusting after 3 months or so if necessary.

More generally you will probably find it advantageous to consider using the varchar2(20) datatype which is a variable length character field. If you had billions of rows the storage saving might be quite significant.

--
Niall Litchfield
Oracle DBA
Audit Commission UK

"Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message
news:3bb07001$0$231$ed9e5944_at_reading.news.pipex.net...


> the number datatype takes anything up to 21 bytes to store (for really

> really big numbers). The char(30) columns will take 30 bytes each.

Therefore


> each row could contain up to

>

> 30*30  + 21  = 921 bytes of data. There is then a small overhead but to be

> honest given your example I'd assume each row took 1k to store. This

> overestimates and makes the maths easy your example gives a table size of

3m


> and 10k per day added.  In practice in fact what I do, rather than follow

> the various convoluted calculation measures that there are is

>

> 1. estimate the current size of the data. If you already have it in some

> other form then so much the better just see how much room it currently

> takes.

> 2. Add 25% for growth.

> 3. allocate 50% of data size for index storage, any more and you've

probably


> got your indexing wrong.

>

> The reason being that any estimate will be wrong and after a while (say 3

> months) you can see what the trend in storage actually is and adjust

> accordingly.

>

>

> --

> Niall Litchfield

> Oracle DBA

> Audit Commission UK

>

>

> "Paul Meier" <stefan.porges_at_berlin.de> wrote in message

> news:9opjuj$eb0q9$1_at_ID-109621.news.dfncis.de...

> > Hi and  good morning and thanks to kevin for the first hint,

> >

> > could somebody please help. I dont know, how to calculate the needed

> > tablespace.

> > Sample table with 30 columns( 1 - column Number and 29 columns

char(20) )


> >                     initial data = 3000 rows

> >                     average growth = 10 rows per day

> >

> > How many kb - tablespace should i furnish and why?

> >

> > Thanks a lot

> >

> > Paul

> >

> >

>

>