On 2013-10-01 10:07:19 -0400, Robert Haas wrote:
> - It seems that HeapSatisfiesHOTandKeyUpdate is now
> HeapSatisfiesHOTandKeyandCandidateKeyUpdate. Considering I think this
> was merely HeapSatisfiesHOTUpdate a year ago, it's hard not to be
> afraid that something unscalable is happening to this function. On a
> related node, any overhead added here costs broadly; I'm not sure if
> there's enough to worry about.
Ok, I had to think a bit, but now I remember why I think these changes
are not really problem: Neither the addition of keys nor candidate keys
will add any additional comparisons since the columns compared for
candidate keys are a subset of the set of key columns which in turn are a
subset of the columns checked for HOT. Right?
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services