Re: Pluggable storage

On Tue, Jun 13, 2017 at 4:50 AM, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>
wrote:

> On Fri, Oct 14, 2016 at 7:26 AM, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
> wrote:
>
>> I have sent the partial patch I have to Hari Babu Kommi. We expect that
>> he will be able to further this goal some more.
>
>
> Thanks Alvaro for sharing your development patch.
>
> Most of the patch design is same as described by Alvaro in the first mail
> [1].
> I will detail the modifications, pending items and open items (needs
> discussion)
> to implement proper pluggable storage.
>
> Here I attached WIP patches to support pluggable storage. The patch series
> are may not work individually. Still so many things are under development.
> These patches are just to share the approach of the current development.
>
> Some notable changes that I did to make the patch work:
>
> 1. Added storageam handler to the slot, this is because not all places
> the relation is not available in handy.
> 2. Retained the minimal Tuple in the slot, as this is used in HASH join.
> As per the first version, I feel it is fine to allow creating HeapTuple
> format data.
>
> Thanks everyone for sharing their ideas in the developer's unconference at
> PGCon Ottawa.
>
> Pending items:
>
> 1. Replacement of Tuple with slot in Trigger functionality
> 2. Replacement of Tuple with Slot from storage handler functions.
> 3. Remove/minimize the use of HeapTuple as a Datum.
> 4. Replace all references of HeapScanDesc with StorageScanDesc
> 5. Planner changes to consider the relation storage during the planning.
> 6. Any planner changes based on the discussion of open items?
> 7. some Executor changes to consider the storage advantages?
>
> Open Items:
>
> 1. The BitmapHeapScan and TableSampleScan are tightly coupled with
> HeapTuple and HeapScanDesc, So these scans are directly operating
> on those structures and providing the result.
>

What about vacuum? I see vacuum is untouched in the patchset and it is not
mentioned in this discussion.
Do you plan to override low-level function like heap_page_prune(),
lazy_vacuum_page() etc., but preserve high-level logic of vacuum?
Or do you plan to let pluggable storage implement its own high-level vacuum
algorithm?

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company