I’m trying to calculate the size of a few tables as stated here, but I can’t find the block header size variable
How do I get it? Is it some kind of formula?
I’m using Oracle 10g
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I’m trying to calculate the size of a few tables as stated here, but I can’t find the block header size variable
How do I get it? Is it some kind of formula?
I’m using Oracle 10g
This site has a good discussion on the format of the block header: http://www.adp-gmbh.ch/ora/concepts/db_block.html. Basically the block header = fixed header + transaction header + table directory + row directory. Here are the individual pieces:
fixed header = 57 bytes
transaction header = between 23*inittrans and 23*maxtrans
table directory = 4*number of tables (usually 1 unless you’re using clusters)
row directory = 2*stored rows
In short while you can come up with a rough estimate, it’s not a fixed size for each data block.