Re: Determining right size for max_fsm_pages on large

Vivek Khera writes:

> how many actual pages of data (and index) do you have?  you want to
> see how many relpages you're relations are using in the pg_class
> view.

In 1 database:
select relname,relpages,reltuples from pg_class order by reltuples desc
limit 7;
             relname              | relpages |  reltuples
----------------------------------+----------+-------------
 pg_toast_988195_index            |   148159 | 3.87392e+07
 pg_toast_988195                  |  9551848 | 3.87391e+07
 pg_toast_988154_index            |   123991 | 3.24807e+07
 pg_toast_988154                  |  8113192 | 3.24807e+07
 msgrcpnts_mssgid_recpttp_recptid |    11192 | 2.52415e+06
 messagerecipients                |    16078 | 2.52415e+06
 messagerecipients_pkey           |     6375 | 2.52415e+06



In another:
select relname,relpages,reltuples from pg_class order by reltuples desc
limit 7;
          relname          | relpages | reltuples
---------------------------+----------+------------
 pg_toast_2352480          | 14902626 | 3.0651e+07
 pg_toast_2352480_index    |   222896 | 3.0651e+07
 archiveque_host           |    11848 |     831494
 archiveque_messageid      |    13223 |     831494
 archiveque_pkey           |     4732 |     831494
 archiveque                |   161097 |     831494
 archiveque_archive_que_id |     5119 |     831494


>  i would venture to say if you have deleted rows in every
> single page, you'd want at least one entry per page of your table(s).

So about 15 million according to the above?

> once you're done with your migration, you should consider running a
> cluster on the big tables

Plan to.
Data will divide nicely by dates. All searches will
have date parameters.

After the migration is done and it is stable I should bring the value down?