Simon Riggs <[EMAIL PROTECTED]> wrote: > * For Highly Non-Unique Data we can use Duplicate Compression > The latter is the technique used by Bitmap Indexes. Efficient, but not > useful for unique/nearly-unique data
I heard that GIN has already had duplicate-compression feature. http://www.sai.msu.su/~megera/oddmuse/index.cgi/Gin | Gin consists of a B-tree index constructed over entries (ET, entries tree), | where each entry is an element of the indexed value (element of array, | lexeme for tsvector) and where each tuple in a leaf page is either a | pointer to a B-tree over item pointers (PT, posting tree), or a list of | item pointers (PL, posting list) if the tuple is small enough. If GIT comes, can we merge or share some modules between btree and gin? I guess the page layout of GIT is better than ET/PT pair when the index size are larger than main memory because the key and item pointers are placed in near pages. Gin-over-btree might be useful some usages of inverted indexes. Regards, --- ITAGAKI Takahiro NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
