Re: Patch: Write Amplification Reduction Method (WARM)

On Sun, Mar 19, 2017 at 3:05 AM, Pavan Deolasee
<pavan(dot)deolasee(at)gmail(dot)com> wrote:
> On Thu, Mar 16, 2017 at 12:53 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Wed, Mar 15, 2017 at 3:44 PM, Pavan Deolasee
>> <pavan(dot)deolasee(at)gmail(dot)com> wrote:
>> > I couldn't find a better way without a lot of complex infrastructure.
>> > Even
>> > though we now have ability to mark index pointers and we know that a
>> > given
>> > pointer either points to the pre-WARM chain or post-WARM chain, this
>> > does
>> > not solve the case when an index does not receive a new entry. In that
>> > case,
>> > both pre-WARM and post-WARM tuples are reachable via the same old index
>> > pointer. The only way we could deal with this is to mark index pointers
>> > as
>> > "common", "pre-warm" and "post-warm". But that would require us to
>> > update
>> > the old pointer's state from "common" to "pre-warm" for the index whose
>> > keys
>> > are being updated. May be it's doable, but might be more complex than
>> > the
>> > current approach.
>>
>> /me scratches head.
>>
>> Aren't pre-warm and post-warm just (better) names for blue and red?
>>
>
> Yeah, sounds better.

My point here wasn't really about renaming, although I do think
renaming is something that should get done. My point was that you
were saying we need to mark index pointers as common, pre-warm, and
post-warm. But you're pretty much already doing that, I think. I
guess you don't have "common", but you do have "pre-warm" and
"post-warm".

--
Robert Haas
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