[Xapian-devel] GSOC 2012 : QueryParser Reimplementation

[Olly Betts]

On Sun, Mar 25, 2012 at 09:27:19PM +0530, Sehaj Singh Kalra wrote:
> I have a question - Does Xapian at present cache the result at any level ?
> If not, then I can add the functionality of caching ("after" the Query has
> been parsed as you rightfully explained that it's probably better to cache
> after the QueryParser) in my proposal.

Xapian doesn't explicitly cache results between queries, though the
operating system will cache recently read disk blocks, which makes a
big difference - if you turn on the machine and time running the same
query twice in a row, it'll be much faster the second time, entirely
due to this.

Make sure you don't bite off too much though - it would be better to
fully implement a replacement QueryParser and get it merged than to
partly implement a replacement QueryParser and partly implement a query
result cache.  The current QueryParser supports quite a lot of features
and those all need to work at least as well in the replacement as they
do currently before we can make the switch.

Cheers,
    Olly