You'll still need to call rewrite, but it needs to be done per-reader, so you'll need to cache the queries *before* they're rewritten, and then call rewrite whenever you create a new IndexReader. Otherwise you'll get incorrect scores, and possibly missed hits as well.
Alan Woodward www.flax.co.uk On 8 Jun 2015, at 11:46, Anna Maier wrote: > Hi Alan, > > you are right, we are calling rewrite on our query at some point. Ok, it > would probably be an option to take that out. > Thanks for the hint! > > Best, > Anna > > -----Original Message----- > From: Alan Woodward [mailto:a...@flax.co.uk] > Sent: Montag, 8. Juni 2015 12:23 > To: java-user@lucene.apache.org > Subject: Re: Memory problem with TermQuery > > Hi Anna, > > In normal usage, perReaderTermState will be null, and TermQuery will be very > lightweight. It's in particular expert use cases (generally after queries > have been rewritten against a specific IndexReader) that the > perReaderTermState will be initialized. Are you cacheing rewritten queries > somehow? > > Alan Woodward > www.flax.co.uk > > > On 8 Jun 2015, at 10:49, Anna Maier wrote: > >> Hi, >> >> we ran into a memory problem with TermQuery: in our program, we build a >> TermQuery object from the user input and pass it around, to be able to >> different things, like execute the query again and so on. So, the TermQuery >> object can potentially exist for some time. >> Now it turns out, that a TermQuery keeps a reference to an IndexReader (via >> the perReaderTermState field). >> This keeps our program from throwing old readers away when new ones are >> opened. This has quite an impact on the required memory, especially for big >> indices. It is not feasible anymore now to keep a reference to a TermQuery >> for longer. >> >> I'm wondering: is this a bug? After all, I would have expected the TermQuery >> to be a lightweight object. Or is the TermQuery not intended to be passed >> around in the program at all? >> >> Best, >> Anna >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org >> For additional commands, e-mail: java-user-h...@lucene.apache.org >> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org >
