Select max(id) causes AccessExclusiveLock?

[Edson Richter <edsonrichter@xxxxxxxxxxx>]

On table

create table MyTableName (
  id integer not null primary key,
  seqYear char(4),
  seqCount integer,
  ...)

Where id is primary key and (seqYear, seqCount) is a unique index.
Table facts: about 40 fields, 1 million records.

When I issue a

select max(id) from MyTableName


Postgres 9.2.7 is scaling a AccessExclusiveLock and causing large delays.

Is that expected? Is there a way to avoid the AccessExclusiveLock?

Thanks,

Edson


--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general