Re: Bloom Filter lookup for hash joins

On Wed, Jun 26, 2013 at 5:47 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On 26 June 2013 07:46, Atri Sharma <atri(dot)jiit(at)gmail(dot)com> wrote:
>
>>
>> I have been researching bloom filters and discussed it on IRC with
>> RhodiumToad and David Fetter, and they pointed me to the various
>> places that could potentially have bloom filters, apart from the
>> places that already have them currently.
>>
>> I have been reading the current implementation of hash joins, and in
>> ExecScanHashBucket, which I understand is the actual lookup function,
>> we could potentially look at a bloom filter per bucket. Instead of
>> actually looking up each hash value for the outer relation, we could
>> just check the corresponding bloom filter for that bucket, and if we
>> get a positive, then lookup the actual values i.e. continue with our
>> current behaviour (since we could be looking at a false positive).
>
>
> Exactly this was suggested by me on the NTUP_PER_BUCKET thread last week.
>
> Probably good idea to join in there also.
>

Great.I would love to assist you in implementing this, if possible.

Regards,

Atri

--
Regards,

Atri
l'apprenant