Re: Toasting more system-table columns - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Toasting more system-table columns
Date
Msg-id 19269.965332667@sss.pgh.pa.us
Whole thread Raw
In response to Re: Toasting more system-table columns  ("Mark Hollomon" <mhh@nortelnetworks.com>)
List pgsql-hackers
"Mark Hollomon" <mhh@nortelnetworks.com> writes:
> Tom Lane wrote:
>> pg_statistic to cope with long
>> min/max/common values (not sure about this).

> I would think pg_statistic would be a 'must'.

Well, it's not a "must" because the code copes fine now (there's a test
in there that simply drops pg_statistic tuples that won't fit).

Question is whether we need good selectivity estimation on columns where
the min/max/common values exceed 8K total (when represented in text form).
Or for that matter whether the estimates we derive from such values are
really useful ...
        regards, tom lane


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