On Tue, Jan 24, 2017 at 11:41 AM, Ashutosh Sharma <ashu.coe...@gmail.com> wrote: >>> Secondly, we will have to input overflow block number as an input to >>> this function so as to determine the overflow bit number which can be >>> used further to identify the bitmap page. >>> >> >> I think you can get that from bucket number by using BUCKET_TO_BLKNO. >> You can get bucket number from page's opaque data. So, if we follow >> that then you can have a prototype of a function as >> hash_bitmap_info(index_oid, page bytea) which will be quite similar to >> other API's exposed by this module. >> > > AFAIU, BUCKET_TO_BLKNO will give us the block number of a primary > bucket page rather than overflow page and what we want is an overflow > block number so as to determine the overflow bit number which can be > used further to identify the bitmap page. >
Right. > If we pass overflow page as > an input to hash_bitmap_info() we won't be able to get it's block > number. > I think we can get it by using its prev block number, but not sure if it is worth the complexity, so let's keep the interface as proposed by you. TBH, I am not sure how important is to expose this (hash_bitmap_info()) function, but let's keep it and see if committer has any opinion on this API. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
