Re: Experimenting with hash join prefetch

Hi, Thomas!
> 14 окт. 2018 г., в 9:18, Thomas Munro <thomas.munro@enterprisedb.com> написал(а):
> 
> +               /* Prefetch the bucket for the next key */
> +               uint32 next_hash = hash_uint32(DatumGetInt32(keyval) + 1);
> +               uint32 next_bucket = next_hash % hashtable->nbuckets;
> +               __builtin_prefetch(&hashtable->buckets.unshared[next_bucket]);


+1, I also think that we should use __builtin_prefetch these days (years, actually).
Exactly after listening Anastassia Ailamaki's (author of referenced paper) talk on VLDB I've proposed to do that for B-tree [0], but did not really pursuit that idea.

[0] https://www.postgresql.org/message-id/3B774C9E-01E8-46A7-9642-7830DC1108F1%40yandex-team.ru