Re: Why is restored database faster? - Mailing list pgsql-performance

Dennis, Shridhar, and Neil,

Thanks for your input.  Here are my responses:

I ran VACUUM FULL on the table in question.  Although that did reduce "Pages"
and "UnUsed", the "SELECT *" query is still much slower on this installation
than in the new, restored one.

  Old server:
 # VACUUM FULL abc;
  VACUUM
  # VACUUM VERBOSE abc;
  NOTICE: --Relation abc--
 NOTICE: Pages 1526: Changed 0, Empty 0; Tup 91528; Vac 0, Keep 0, UnUsed 32.
     Total CPU 0.07s/0.52u sec elapsed 0.60 sec.
 VACUUM

  New server:
 # VACUUM VERBOSE abc;
  NOTICE: --Relation abc--
  NOTICE: Pages 1526: Changed 0, Empty 0; Tup 91528; Vac 0, Keep 0, UnUsed 0.
    Total CPU 0.02s/0.00u sec elapsed 0.02 sec.
 VACUUM

max_fsm_pages is at its default value, 10000.

People don't have the practice of dumping and restoring just for the purpose of
improving performance, do they?

Neil asked how much disk space the database directory takes on each machine.
 What directory is of interest?  The whole thing takes up about 875 MB on each
machine.

-David