Re: Shared detoast Datum proposal

On 3/6/24 07:09, Nikita Malakhov wrote:
> Hi,
> 
> In addition to the previous message - for the toast_fetch_datum_slice
> the first (seems obvious) way is to detoast the whole value, save it
> to cache and get slices from it on demand. I have another one on my
> mind, but have to play with it first.
> 

What if you only need the first slice? In that case decoding everything
will be a clear regression.

IMHO this needs to work like this:

1) check if the cache already has sufficiently large slice detoasted
(and use the cached value if yes)

2) if there's no slice detoasted, or if it's too small, detoast a
sufficiently large slice and store it in the cache (possibly evicting
the already detoasted slice)


regards

-- 
Tomas Vondra
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