Re: Should I CLUSTER on PRIMARY KEY

Robert James wrote:
> I would like to CLUSTER a table on its PRIMARY KEY.  Now, I haven't
> explicitly defined and named an index for this table - but the primary
> key defines one.   How can I tell Postgres to CLUSTER on it?

Get the index name:

\d tablename

Right at the bottom it will have the index names:

Indexes:
     "a_pkey" PRIMARY KEY, btree (a)


then cluster:

# cluster tablename using a_pkey;
CLUSTER


> Also: If I define an index on a PK, will Postgres make a second one, or
> realize its redundnant?

Depends how you define it (I think). What's your create table statement
look like?

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