On 8/9/16 6:44 PM, Claudio Freire wrote:
> Since we can lookup all occurrences of k1=a index=0 and k2=a index=0,
> and in fact we probably did so already as part of the update logic
That's a change from what currently happens, right?
The reason I think that's important is that dropping the assumption that
we can't safely re-find index entries from the heap opens up other
optimizations, ones that should be significantly simpler to implement.
The most obvious example being getting rid of full index scans in
vacuum. While that won't help with write amplification, it would reduce
the cost of vacuum enormously. Orders of magnitude wouldn't surprise me
in the least.
If that's indeed a prerequisite to WARM it would be great to get that
groundwork laid early so others could work on other optimizations it
would enable.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
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