Correct, that's the way we use it.
On 1/12/10, Simone Chiaretta <simone.chiare...@gmail.com> wrote:
> 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"
>
--
Jokin
