Delete performance

Is there a performance issue deleting rows of a table where one
field is toasted text?

I have a database with two different tables, and delete both based
on timestamp criteria. One is lightning fast, even for
thousands of rows, the other is very slow.

The first table has a timestamp criteria that is discrete, i.e.,
there are large number of rows with the same timestamp. This
table has no toasted fields. This deletes very quickly.

The second table has a timestamp value that is more of a
continuous function (only a few rows will share the same
second of time). A single field is toasted, and contains
2K to 15K characters. This deletes very slowly, like only
a couple of records a second. The table structure is pretty
simple:

Attribute | Type | Modifier
------------+--------------------------+----------
name | text | not null
parse_time | timestamp with time zone | not null
data | text |

Any hints as to what's going on? Postgresql 7.1.3,
HP-UX 10.20........

--
P. J. "Josh" Rovero Sonalysts, Inc.
Email: rovero@sonalysts.com www.sonalysts.com 215 Parkway North
Work: (860)326-3671 or 442-4355 Waterford CT 06385
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