[Xapian-devel] About memory index/search in multithread program

[Yanxiong Lu]

That code can't work, it is pseudo-code.

As I already tried to explain, if you're concerned about performance,
the current inmemory backend isn't the answer you are looking for.

I will write a memory based SE with WAND merge algorithm and proximity
similarity
algorithm(BM25 don't use position).
Thank you very much.


2014-06-26 14:33 GMT+08:00 Olly Betts <olly at survex.com>:

> On Thu, Jun 26, 2014 at 01:19:20PM +0800, Yanxiong Lu wrote:
> > There may be some solutions，for example
> > class XAPIAN
> > {
> >     *static* int InitDatabase();  //for reading only, do not need lock,
> but
> > if writing use lock
> >     int Search(); //safe in one object, do not need lock
> > };
> > XIPIAN xp[ THREAD_NUM ];
> >
> > one thread use one object, they use one database.
> > these can be in memory with one database.
>
> As I already tried to explain, if you're concerned about performance,
> the current inmemory backend isn't the answer you are looking for.
> Eliminating the need for the user to lock around searches isn't going to
> magically solve that.
>
> I don't really see how your 6 line sketch above helps either.  Xapian
> makes *NO* thread-safety guarantees - even in the "reading only" case
> you should be locking.  Even if it happens to work currently, there's
> no guarantee it'll work in the next release.
>
> Cheers,
>     Olly
>
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