"Bruce Momjian" <bruce@momjian.us> writes:
> Tom Lane wrote:
>> Bruce Momjian <bruce@momjian.us> writes:
>> > I am thinking we are best just doing the index chain we already have to
>> > read.
>>
>> > If you are modifying the table (like with UPDATE) it makes sense to be
>> > more aggressive and do the whole page because you know there are
>> > probably other table modifications, but for an index lookup there isn't
>> > any knowledge of whether the table is being modified so looking at more
>> > than we need seems like overkill.
>>
>> Uh, why would any of this code at all execute during a pure lookup?
>
> No idea. It seems an index lookup tries to prune a heap chain, and he
> was asking if it should look at other chains on the page; I said not.
> Whether the index lookup should prune the heap chain is another issue.
Pruning chains is kind of the whole point of the exercise no?
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com