On 26 June 2013 07:46, Atri Sharma 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).
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).
Probably good idea to join in there also.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
