Hi, I wonder, how much space derby will use on disk for each row of a table, and how much space will be used for each field (column value).
Is it possible to give rules of the following kind: Every field of type INTEGER will take N bytes (N=4?), every field of type VARCHAR(X) will take I*X+J bytes (I, J =?), every field of type VARCHAR with NULL value will take K bytes, every row will take the sum of all field-widths plus L bytes, ... In case VARCHAR is UTF-8 encoded it will already help to say that the length of a field of that type is the length in UTF-8 encoding plus J bytes. I already found this [1] article but I am not sure that I quite understand it. I would conclude, that a field of type INTEGER would use 9 bytes, i.e. more than twice the number of bytes the value itself has... (1 byte for the status, 4 bytes for the fieldDataLength and 4 bytes for the fieldData (of type INTEGER). What is the length of a CompressedInt, by the way? From the article I don't really understand the relation row <-> record and column-value <-> field. Thanks in advance, Karl [1] http://db.apache.org/derby/papers/pageformats.html
