On 4 August 2016 at 17:31, Andres Freund <andres@anarazel.de> wrote:
> Hi,
>
> On 2016-08-04 16:29:09 +0530, Pavan Deolasee wrote:
>> Indexes whose values do not change do not require new index pointers. Only
>> the index whose key is being changed will need a new index entry. The new
>> index entry will be set to the CTID of the root line pointer.
>
> That seems to require tracing all hot-chains in a page, to actually
> figure out what the root line pointer of a warm-updated HOT tuple is,
> provided it's HOT_UPDATED itself. Or have you found a smart way to
> figure that out?
Hmm, sorry, I did think of that point and I thought I had added it to the doc.
So, yes, I agree - re-locating the root is the biggest downside to
this idea. Perhaps Pavan has other thoughts?
I think its doable, but it will be fiddly.
--
Simon Riggs http://www.2ndQuadrant.com/
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