Jai
I couldn't follow all the details of your calculation. I would have
expected to see a calculation for the number of rows per block. Once you
know how many rows you can pack into a block, then you can estimate the
number of blocks you will need. Maybe you have it in there and I just
Are you actually going to use the formula ?
And I thought that Oracle had dropped the formua from recent versions
of its RDBMS documentation [8.1 and upwards].
The only real way you can get an approximation [not the exact projection]
of the size is to load some data and then analyze the tables.
Jai,
The formula you are using is reasonably accurate, but not very useful.
One of the main problems I have found with this approach is that the number
of rows is not usually known. The business side and designers might have
an idea of data sizes, but the reality is that most times they are
The voice of reason! Thanks Dan. How many times have I been asked for an
estimate of an index size (including every tiny overhead and spare byte)
without knowing how many rows will be inserted.
So they need an exact calculation based on a very rough estimate.
As a result my calculation method has
Daniel - Excellently put. The other factor you can usually only estimate is
the row size, until you get some test data. The old engineer in me says that
if you can only guess at the row size and number of rows, then don't pretend
the exact formula is going to do much for you. I started with a
Dear All,
I have a task on hand to size a database for our application. I have used the Oracle rule to find out the rowsize of rows in a table.
1.Space available for the data (SAD) = data block size block header size = db_block_size kcbh ub4 ktbbh (initrans -1)* ktbit kdbh
2.
