OK, so I can create the query parser each time, using the analyzer I created
at the search engine startup? Correct?
Simone
On Tue, Jan 12, 2010 at 12:28 AM, Jokin Cuadrado <joki...@gmail.com> wrote:
> The queryparser it's not thread safe, so you must use a new one in
> every request, however, is very lightweight, because the bigger
> complexity comes from the underlying analyzer, and this one it's
> thread safe.
>
> On 1/12/10, Simone Chiaretta <simone.chiare...@gmail.com> wrote:
> > I'm trying to go live with our search engine implementation based on
> > Lucene.net.
> > Unfortunately we have to keep it inside our appdomain in the web
> application
> > to make it work in shared hosting scenario.
> >
> > But we are getting quite a few problems, so I was wondering if there are
> > some issues with concurrent access:
> > 1 - is the QueryParser thread safe? Can I make it one at the beginning of
> > the times and reuse it in all my queries? or do I've to create one each
> > time?
> > I'm asking because I'm getting strange errors like:
> >
> > ystem.InvalidOperationException: Collection was modified; enumeration
> > operation may not execute. at
> > System.Collections.ArrayList.ArrayListEnumeratorSimple.MoveNext() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_add_error_token(Int32 kind, Int32
> > pos) at Lucene.Net.QueryParsers.QueryParser.Jj_scan_token(Int32 kind)
> > at Lucene.Net.QueryParsers.QueryParser.Jj_3_1() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_rescan_token() at
> > Lucene.Net.QueryParsers.QueryParser.GenerateParseException() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_consume_token(Int32 kind) at
> > Lucene.Net.QueryParsers.QueryParser.Clause(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Query(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Parse(String query) at
> > Subtext.Framework.Services.SearchEngine.SearchEngineService.Search(String
> > queryString, Int32 max, Int32 blogId, Int32 entryId)
> >
> > Which looks to me like a threading issue.
> >
> > I also got this one:
> >
> > Lucene.Net.QueryParsers.QueryParser+LookaheadSuccess: Error in the
> > application.
> > at Lucene.Net.QueryParsers.QueryParser.Jj_scan_token(Int32 kind) at
> > Lucene.Net.QueryParsers.QueryParser.Jj_3R_2() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_3R_2() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_rescan_token() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_3_1() at
> > Lucene.Net.QueryParsers.QueryParser.GenerateParseException() at
> > Lucene.Net.QueryParsers.QueryParser.Jj_consume_token(Int32 kind) at
> > Lucene.Net.QueryParsers.QueryParser.Jj_consume_token(Int32 kind) at
> > Lucene.Net.QueryParsers.QueryParser.Term(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Clause(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Clause(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Query(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Query(String field) at
> > Lucene.Net.QueryParsers.QueryParser.Parse(String query) at
> > Lucene.Net.QueryParsers.QueryParser.Parse(String query) at
> > Subtext.Framework.Services.SearchEngine.SearchEngineService.Search(String
> > queryString, Int32 max, Int32 blogId, Int32 entryId)
> >
> > And this one:
> >
> > Lucene.Net.QueryParsers.ParseException: Cannot parse 'what is css
> > url': Encountered
> > "what is css url" at line 1, column 0. Was expecting one of: <NOT>
> > ... "+"
> > ... "-" ... "(" ... "*" ... <QUOTED> ... <TERM> ...
> > <PREFIXTERM> ... <WILDTERM> ... "[" ... "{" ...
> > <NUMBER> ...
> > at Lucene.Net.QueryParsers.QueryParser.Parse(String query)
> >
> > Which is fine if I really added an invalid character in the query, but
> "what
> > is css url" looks to me like it's a valid query.
> >
> > What I'm doing is, to avoid creating a new query parser for each query,
> to
> > "cache" the same as variable inside the singleton class that holds the
> > search engine.
> > Is this a good approach? or a bad one? (I guess bad since this all seem
> to
> > be threading issues).
> > Is creating a new query parser for each query a performance problem?
> >
> > Thank you
> > Simone
> >
> > --
> > Simone Chiaretta
> > Microsoft MVP ASP.NET - ASPInsider
> > Blog: http://codeclimber.net.nz
> > RSS: http://feeds2.feedburner.com/codeclimber
> > twitter: @simonech
> >
> > Any sufficiently advanced technology is indistinguishable from magic
> > "Life is short, play hard"
> >
>
>
> --
> Jokin
>
--
Simone Chiaretta
Microsoft MVP ASP.NET - ASPInsider
Blog: http://codeclimber.net.nz
RSS: http://feeds2.feedburner.com/codeclimber
twitter: @simonech
Any sufficiently advanced technology is indistinguishable from magic
"Life is short, play hard"
