Re: Minmax indexes - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Minmax indexes
Date
Msg-id 53E74759.6010703@vmware.com
Whole thread Raw
In response to Re: Minmax indexes  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
On 08/10/2014 12:22 PM, Simon Riggs wrote:
> On 8 August 2014 16:03, Heikki Linnakangas <hlinnakangas@vmware.com> wrote:
>
>> 1. MMTuple contains the block number of the heap page (range) that the tuple
>> represents. Vacuum is no longer needed to clean up old tuples; when an index
>> tuples is updated, the old tuple is deleted atomically with the insertion of
>> a new tuple and updating the revmap, so no garbage is left behind.
>
> What happens if the transaction that does this aborts? Surely that
> means the new value is itself garbage? What cleans up that?

It's no different from Alvaro's patch. The updated MMTuple covers the 
aborted value, but that's OK from a correctnes point of view.

- Heikki



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