On Tue, Dec 28, 2010 at 10:57 AM, xu cheng <xcheng....@gmail.com> wrote: > hi simon > thanks for replying very much. > after reading the source code with your suggestion, here's my understanding, > and I don't know whether it's right: > the DocumentsWriter actually don't create threads, but the codes that use > DocumentsWriter can do the multithreading(say, several threads call > updateDocument). and each thread has its DocumentsWriterThreadState, in the > mean while, each DocumentsWriterThreadState has its own objects(the > *PerThread such as DocFieldProcessorPerThread, DocInverterPerThread and so > on ) > as the methods of DocumentsWriter are called by multiple threads, for > example, 4 threads, there are 4 DocumentsWriterThreadState objects, and 4 > index chains, ( each index chain has it's own *PerThread objects , to > process the document). > am I right??
that sounds about right simon > thanks for replying again! > > > 2010/12/28 Simon Willnauer <simon.willna...@googlemail.com> >> >> Hey there, >> >> so what you are looking at are classes that are created per Thread >> rather than shared with other threads. Lucene internally rarely >> creates threads or subclasses Thread, Runnable or Callable >> (ParallelMultiSearcher is an exception or some of the merging code). >> Yet, inside the indexer when you add (update) a document Lucene >> utilizes the callers thread rather than spanning a new one. When you >> look at DocumentsWriter.java there should be a method callled >> getThreadState. Each indexing thread, lets say in updateDocument, gets >> its Thread-Private DocumentsWriterThreadState. This thread state holds >> a DocConsumerPerThread obtained from the DocumentsWriters DocConsumer >> (see the indexing chain). DocConsumerPerThread in that case is some >> kind of decorator that hold other DocConsumerPerThread instances like >> TermsHashPerThread etc. >> >> The general pattern is for each DocConsumer you can get a >> DocConsumerPerThread for your indexing thread which then consumes the >> document you are processing right now. >> >> I hope that helps.... >> >> simon >> >> >> On Tue, Dec 28, 2010 at 4:19 AM, xu cheng <xcheng....@gmail.com> wrote: >> > hi all: >> > I'm new to dev >> > these days I'm reading the source code in the index package >> > and I was confused. >> > there are classes with suffix PerThread such as >> > DocFieldProcessorPerThread, >> > DocInverterPerThread, TermsHashPerThread, FreqProxTermWriterPerThread. >> > in this mailing-list, I was told that they are multithreaded. >> > however, there are some difficulties for me to understand! >> > I see no sign that they inherited from the Thread , or implement the >> > Runnable, or something else?? >> > how do they map to the OS thread?? >> > thanks ^_^ >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org >> For additional commands, e-mail: dev-h...@lucene.apache.org >> > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org
