Cristina M wrote: > I posted to the general list, and didn't receive any replies. > Therefore, I am trying this list now, hopefully this is the right > mailing list for this type of questions. > > I am trying to compute the no of pages of a table. I am using the formula : > > pages = ( columns width + 28) * no. of rows / block size
Keep in mind that if you have varchar(1000) and store 30 bytes of text, it will use 30+4, not 1000+4. Very long attributes may be compressed and/or stored in a side table called the TOAST table; only a pointer to it remains on the base table (which is some 20 bytes long I think). Also keep in mind that there's a lot of space lost to alignment considerations, so don't expect things to match down to the last byte. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
