Re: a fast bloat measurement tool
Abhijit Menon-Sen <ams@2ndquadrant.com>
From: Abhijit Menon-Sen <ams@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2014-04-03T04:33:20Z
Lists: pgsql-hackers
At 2014-04-02 20:10:54 -0400, robertmhaas@gmail.com wrote: > > I think it might underestimate free space relative to tuples because > the free space map isn't guaranteed to be completely correct. But I > guess you knew that already... Yes, and tuple_len is already a slight overestimate (because it counts the line pointer array as live tuple space for skipped pages). But for the speedup it provides, I believe the result is still useful. I'll mention the potential for free-space inaccuracy in the README. -- Abhijit