On Mon, Sep 2, 2019 at 12:08 PM Hick Gunter <[email protected]> wrote:
> Back in 2011 I implemented a virtual table using the "fastbit" library by > John Wu of the Lawrence Berekely National Laboratory. This allowed selects > of the form > > SELECT ... FROM <base_table> WHERE rowid IN (SELECT rowid FROM > <fastbit_index> WHERE <constraints>); > Did it work well? Did you get any speedup compared to a normal BTree index? Available anywhere? How low the cardinality of indexed columns value-space needs to be to benefit from a bitmap index? > provided that the data had been inserted before by running > > INSERT INTO <fastbit_index> SELECT rowid,<indexed fields>; Custom (user-defined) indexes is an area that I'd welcome in SQLite. You can work around it as you did above, but that implies the index maintenance rests on the user's shoulders. While it would be relatively easy I suspect for SQLite core to notify a custom index of table changes. Conversely, you can't use SQLite (sole for now) BTree indexes with a virtual table, AFAIK, (I have a doubt all of a sudden...), the vtable must do all the indexing itself. _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
