Simon Riggs wrote:
On Mon, 2007-03-12 at 13:56 -0400, Tom Lane wrote:

At this point I'm feeling unconvinced that we want it at all.  It's
sounding like a large increase in complexity (both implementation-wise
and in terms of API ugliness) for a fairly narrow use-case --- just
how much territory is going to be left for this between HOT and bitmap

HOT and clustered indexes have considerable synergy. In many tests we've
got +20% performance with them acting together. Neither one achieves
this performance on their own, but together they work very well.

To clarify, Simon is talking about DBT-2 tests we run in November. Clustered indexes don't require HOT per se, but on TPC-C the performance benefit comes from reducing the amount of I/O on the stock table and index, and that's a table that gets updated at a steady rate. Without HOT, the updates will disorganize the table and the performance gain you get from clustered indexes vanishes after a while.

  Heikki Linnakangas

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