Re: Auto-clustering?

you are right, I must have missed it...

Table "public.u"
Column | Type | Modifiers
--------+-----------------------------+-----------
id | integer |
t | timestamp without time zone |
d | text |
Indexes:
"u_d" btree (d)
"u_id" btree (id)
"u_t" btree (t)

filip(at)filip=# select oid, relname, pg_Relation_size(oid) from pg_class where
relname in('u','u_id','u_t','u_d');
oid | relname | pg_relation_size
-------+---------+------------------
64283 | u | 15187968
64289 | u_id | 6758400
64290 | u_t | 6086656
64291 | u_d | 16482304

filip(at)filip=# CLUSTER u USING u_t;
CLUSTER
filip(at)filip=# select oid, relname, pg_Relation_size(oid) from pg_class where
relname in('u','u_id','u_t','u_d');
oid | relname | pg_relation_size
-------+---------+------------------
64283 | u | 12115968
64289 | u_id | 3391488
64290 | u_t | 3391488
64291 | u_d | 8216576
(4 rows)

So CLUSTER is effectively CLUSTER + REINDEX... nice.

W dniu 17 grudnia 2010 10:41 użytkownik Marti Raudsepp <marti(at)juffo(dot)org>napisał:

> 2010/12/17 Filip Rembiałkowski <filip(dot)rembialkowski(at)gmail(dot)com>:
> > regarding clustering: it does not help with index bloat.
>
> I'm almost sure it does, CLUSTER re-creates all indexes from scratch
> after copying the tuples.
>
> Regards,
> Marti
>