finding out actual tuple size

Hi All,

1. I have been reading and the max size of a tuple is 8K.
I have also read that I can it to a larger size in some config file.  Where is
this file? is it called pg_config.h and is the variable called BLKSZ??

2. Is there a way I can find the actual size of the tuple? Do you go into each
column and find the length of each value and sum it up? I am out of ideas..

if someone knows how please shine some light on my situation..

thanks

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Linh Luong