Re: [PERFORM] Select max(foo) and select count(*) optimization

[Mark Kirkwood]

if this situation persists after 'analyze certificate', then you need to:

increase the statistics target 'alter table certificate alter column 
certificate_id set statistics 100' 

or

'vacuum full certificate'

i.e : there are lots of (dead) updated or deleted tuples in the 
relation, distributed in such a way as to throw off analyze's estimate.

regards

Mark

D'Arcy J.M. Cain wrote:

Well, I did this:

cert=# select relpages,reltuples from pg_class where relname= 'certificate';
relpages |  reltuples
----------+-------------
  399070 | 2.48587e+07
(1 row)
Casting seemed to help:

cert=# select relpages,reltuples::bigint from pg_class where relname= 
'certificate';
relpages | reltuples
----------+-----------
  399070 |  24858736
(1 row)

But:

cert=# select count(*) from certificate;
[*Crunch* *Crunch* *Crunch*]
 count
----------
19684668
(1 row)
Am I missing something?  Max certificate_id is 20569544 btw.

 



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