Re: Zero dead tuples, when significant apparent bloat

On Tue, Dec 10, 2013 at 5:05 PM, John Melesky
<john(dot)melesky(at)rentrakmail(dot)com>wrote:

> It seems clear that there were dead tuples, since the table size shrank to
> an eighth of its previous size. Why did analyze not pick that up?
> Am I missing something?
> This is a very large database, so we want to introspect against live/dead
> tuple percentage to minimize the tables we run a VACUUM FULL against.
>

If you willing to install the pgstattuple[1] extension, what does the
output say? Note, there is some overhead on larger tables (disk I/O
primarily)

select * from pgstattuple('your table');

Also, check the output from bloat query at
https://wiki.postgresql.org/wiki/Show_database_bloat

[1] http://www.postgresql.org/docs/current/static/pgstattuple.html