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From Otis Gospodnetic <otis_gospodne...@yahoo.com>
Subject Re: Lucene : avoiding locking
Date Fri, 12 Nov 2004 16:03:39 GMT
Hello,

--- Luke Shannon <lshannon@hypermedia.com> wrote:

> Currently I am experimenting with checking if the index is lock using
> IndexReader.locked before creating a writer. If this turns out to be
> the
> case I was thinking of just unlocking the file.
> 
> Do you think this is a good strategy?

Only if you synchronize well and only if all index-modifying accesses
are contained in the same JVM.  Alternatively, you could add a 'sleep
and retry' logic around the lock check, and perhaps 'give up or force
unlock if you got too much sleep'.

Otis

 
> ----- Original Message ----- 
> From: "Luke Francl" <luke.francl@stellent.com>
> To: "Lucene Users List" <lucene-user@jakarta.apache.org>
> Sent: Friday, November 12, 2004 10:38 AM
> Subject: Re: Lucene : avoiding locking
> 
> 
> > Luke,
> >
> > I also integrated Lucene into a content management application with
> > incremental updates and ran into the same problem you did.
> >
> > You need to make sure only one process (which means, no multiple
> copies
> > of the application writing to the index simultaneously) or thread
> ever
> > writes to the index. That includes deletes as in your code below,
> so
> > make sure that is synchronized, too.
> >
> > Also, you will find that opening and closing the index for writing
> is
> > very costly, especially on a large index, so it pays to batch up
> all
> > changes in a transaction (inserts and deletes) together in one go
> at the
> > Lucene index. If this still isn't enough, you can batch up 5
> minutes
> > worth of changes and apply them at once. We haven't got to that
> point
> > yet.
> >
> > I am curious, though, how many people on this list are using Lucene
> in
> > the incremental update case. Most examples I've seen all assume
> batch
> > indexing.
> >
> > Regards,
> >
> > Luke Francl
> >
> >
> >
> > On Thu, 2004-11-11 at 18:33, Luke Shannon wrote:
> > > Syncronizing the method didn't seem to help. The lock is being
> detected
> > > right here in the code:
> > >
> > > while (uidIter.term() != null
> > >       && uidIter.term().field() == "uid"
> > >       && uidIter.term().text().compareTo(uid) < 0) {
> > >      //delete stale docs
> > >      if (deleting) {
> > >       reader.delete(uidIter.term());
> > >      }
> > >      uidIter.next();
> > >     }
> > >
> > > This runs fine on my own site so I am confused. For now I think I
> am
> going
> > > to remove the deleting of "stale" files etc and just rebuild the
> index
> each
> > > time to see what happens.
> > >
> > > ----- Original Message ----- 
> > > From: <yahootintin-lucene@yahoo.com>
> > > To: "Lucene Users List" <lucene-user@jakarta.apache.org>
> > > Sent: Thursday, November 11, 2004 6:56 PM
> > > Subject: Re: Lucene : avoiding locking
> > >
> > >
> > > > I'm working on a similar project...
> > > > Make sure that only one call to the index method is occuring at
> > > > a time.  Synchronizing that method should do it.
> > > >
> > > > --- Luke Shannon <lshannon@hypermedia.com> wrote:
> > > >
> > > > > Hi All;
> > > > >
> > > > > I have hit a snag in my Lucene integration and don't know
> what
> > > > > to do.
> > > > >
> > > > >  My company has a content management product. Each time
> > > > > someone changes the
> > > > >  directory structure or a file with in it that portion of the
> > > > > site needs to
> > > > >  be re-indexed so the changes are reflected in future
> searches
> > > > > (indexing
> > > > > must
> > > > >  happen during run time).
> > > > >
> > > > >  I have written a Indexer class with a static Index() method.
> > > > > The idea is
> > > > > too
> > > > >  call the method every time something changes and the index
> > > > > needs to be
> > > > >  re-examined. I am hoping the logic put in by Doug Cutting
> > > > > surrounding the
> > > > >  UID will make indexing efficient enough to be called so
> > > > > frequently.
> > > > >
> > > > >  This class works great when I tested it on my own little
> site
> > > > > (I have about
> > > > >  2000 file). But when I drop the functionality into the QA
> > > > > environment I get
> > > > >  a locking error.
> > > > >
> > > > >  I can't access the stack trace, all I can get at is a log
> > > > > file the
> > > > >  application writes too. Here is the section my class wrote.
> > > > > It was right in
> > > > >  the middle of indexing and bang lock issue.
> > > > >
> > > > >  I don't know if the problem is in my code or something in
> the
> > > > > existing
> > > > >  application.
> > > > >
> > > > >  Error Message:
> > > > >  ENTER|SearchEventProcessor.visit(ContentNodeDeleteEvent)
> > > > >  |INFO|INDEXING INFO: Start Indexing new content.
> > > > >  |INFO|INDEXING INFO: Index Folder Did Not Exist. Start
> > > > > Creation Of New
> > > > > Index
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING INFO: Beginnging Incremental update
> > > > > comparisions
> > > > >  |INFO|INDEXING ERROR: Unable to index new content Lock
> obtain
> > > > > timed out:
> > > > >
> > > > >
> > > >
> > >
>
Lock@/usr/tomcat/jakarta-tomcat-5.0.19/temp/lucene-398fbd170a5457d05e2f4d432
> > > > >  10f7fe8-write.lock
> > > > >
> > > > >
> |ENTER|UpdateCacheEventProcessor.visit(ContentNodeDeleteEvent)
> > > > >
> > > > >  Here is my code. You will recognize it pretty much as the
> > > > > IndexHTML class
> > > > >  from the Lucene demo written by Doug Cutting. I have put a
> > > > > ton of comments
> > > > >  in a attempt to understand what is going on.
> > > > >
> > > > >  Any help would be appreciated.
> > > > >
> > > > >  Luke
> > > > >
> > > > >  package com.fbhm.bolt.search;
> > > > >
> > > > >  /*
> > > > >   * Created on Nov 11, 2004
> > > > >   *
> > > > >   * This class will create a single index file for the
> Content
> > > > >   * Management System (CMS). It contains logic to ensure
> > > > >   * indexing is done "intelligently". Based on IndexHTML.java
> > > > >   * from the demo folder that ships with Lucene
> > > > >   */
> > > > >
> > > > >  import java.io.File;
> > > > >  import java.io.IOException;
> > > > >  import java.util.Arrays;
> > > > >  import java.util.Date;
> > > > >
> > > > >  import org.apache.lucene.analysis.standard.StandardAnalyzer;
> > > > >  import org.apache.lucene.document.Document;
> > > > >  import org.apache.lucene.index.IndexReader;
> > > > >  import org.apache.lucene.index.IndexWriter;
> > > > >  import org.apache.lucene.index.Term;
> > > > >  import org.apache.lucene.index.TermEnum;
> > > > >  import org.pdfbox.searchengine.lucene.LucenePDFDocument;
> > > > >  import org.apache.lucene.demo.HTMLDocument;
> > > > >
> > > > >  import com.alaia.common.debug.Trace;
> > > > >  import com.alaia.common.util.AppProperties;
> > > > >
> > > > >  /**
> > > > >   * @author lshannon Description: <br
> > > > >   *   This class is used to index a content folder. It
> > > > > contains logic to
> > > > >   *   ensure only new or documents that have been modified
> > > > > since the last
> > > > >   *   search are indexed. <br
> > > > >   *   Based on code writen by Doug Cutting in the IndexHTML
> > > > > class found in
> > > > >   *   the Lucene demo
> > > > >   */
> > > > >  public class Indexer {
> > > > >   //true during deletion pass, this is when the index already
> > > > > exists
> > > > >   private static boolean deleting = false;
> > > > >
> > > > >   //object to read existing indexes
> > > > >   private static IndexReader reader;
> > > > >
> > > > >   //object to write to the index folder
> > > > >   private static IndexWriter writer;
> > > > >
> > > > >   //this will be used to write the index file
> > > > >   private static TermEnum uidIter;
> > > > >
> > > > >   /*
> > > > >    * This static method does all the work, the end result is
> > > > > an up-to-date
> > > > >  index folder
> > > > >   */
> > > > >   public static void Index() {
> > > > >    //we will assume to start the index has been created
> > > > >    boolean create = true;
> > > > >    //set the name of the index file
> > > > >    String indexFileLocation =
> > > > >
> > > > >
> > > >
>
AppProperties.getPropertyAsString("bolt.search.siteIndex.index.root");
> > > > >    //set the name of the content folder
> > > > >    String contentFolderLocation =
> > > > >  AppProperties.getPropertyAsString("site.root");
> > > > >    //manage whether the index needs to be created or not
> > > > >    File index = new File(indexFileLocation);
> > > > >    File root = new File(contentFolderLocation);
> > > > >    //the index file indicated exists, we need an incremental
> > > > > update of the
> > > > >    // index
> > > > >    if (index.exists()) {
> > > > >     Trace.TRACE("INDEXING INFO: An index folder exists at: "
> +
> > > > >  indexFileLocation);
> > > > >     deleting = true;
> > > > >     create = false;
> > > > >     try {
> > > > >      //this version of index docs is able to execute the
> > > > > incremental
> > > > >      // update
> > > > >      indexDocs(root, indexFileLocation, create);
> > > > >     } catch (Exception e) {
> > > > >      //we were unable to do the incremental update
> > > > >      Trace.TRACE("INDEXING ERROR: Unable to execute
> > > > > incremental update "
> > > > >          + e.getMessage());
> > > > >     }
> > > > >     //after exiting this loop the index should be current
> with
> > > > > content
> > > > >     Trace.TRACE("INDEXING INFO: Incremental update
> > > > > completed.");
> > > > >    }
> > > > >    try {
> > > > >     //create the writer
> > > > >     writer = new IndexWriter(index, new StandardAnalyzer(),
> > > > > create);
> > > > >     //configure the writer
> > > > >     writer.mergeFactor = 10000;
> > > > >     writer.maxFieldLength = 100000;
> > > > >     try {
> > > > >      //get the start date
> > > > >      Date start = new Date();
> > > > >      //call the indexDocs method, this time we will add new
> > > > >      // documents
> > > > >      Trace.TRACE("INDEXING INFO: Start Indexing new
> > > > > content.");
> > > > >      indexDocs(root, indexFileLocation, create);
> > > > >      Trace.TRACE("INDEXING INFO: Indexing new content
> > > > > complete.");
> > > > >      //optimize the index
> > > > >      writer.optimize();
> > > > >      //close the writer
> > > > >      writer.close();
> > > > >      //get the end date
> > > > >      Date end = new Date();
> > > > >      long totalTime = end.getTime() - start.getTime();
> > > > >      Trace.TRACE("INDEXING INFO: All Indexing Operations
> > > > > Completed in "
> > > > >          + totalTime + " milliseconds");
> > > > >     } catch (Exception e1) {
> > > > >      //unable to add new documents
> > > > >      Trace.TRACE("INDEXING ERROR: Unable to index new content
> > > > > "
> > > > >          + e1.getMessage());
> > > > >     }
> > > > >    } catch (IOException e) {
> > > > >     Trace.TRACE("INDEXING ERROR: Unable to create IndexWriter
> > > > > "
> > > > >       + e.getMessage());
> > > > >    }
> > > > >   }
> > > > >
> > > > >   /*
> > > > >    * Walk directory hierarchy in uid order, while keeping uid
> > > > > iterator from
> > > > >  /*
> > > > >    * existing index in sync. Mismatches indicate one of: (a)
> > > > > old documents
> > > > > to
> > > > >  /*
> > > > >    * be deleted; (b) unchanged documents, to be left alone;
> or
> > > > > (c) new /*
> > > > >    * documents, to be indexed.
> > > > >    */
> > > > >
> > > > >   private static void indexDocs(File file, String index,
> > > > > boolean create)
> > > > >     throws Exception {
> > > > >    //the index already exists we do an incremental update
> > > > >    if (!create) {
> > > > >     Trace.TRACE("INDEXING INFO: Incremental Update Request
> > > > > Confirmed");
> > > > >     //open existing index
> > > > >     reader = IndexReader.open(index);
> > > > >     //this gets an enummeration of uid terms
> > > > >     uidIter = reader.terms(new Term("uid", ""));
> > > > >     //jump to the index method that does the work
> > > > >     //this will use the Iteration above and does
> > > > >     //all the "smart" indexing
> > > > >     indexDocs(file);
> > > > >     //this will be true everytime the index already existed
> > > > >     //we are not going to delete documents that are old
> > > > >     if (deleting) {
> > > > >      Trace.TRACE("INDEXING INFO: Deleting Old Content Phase
> > > > > Started. All
> > > > >  Deleted Docs will be listed.");
> > > > >      while (uidIter.term() != null
> > > > >        && uidIter.term().field() == "uid") {
> > > > >       //basically we are deleting all the document we have
> > > > >       // indexed before
> > > > >       Trace.TRACE("INDEXING INFO: Deleting document "
> > > > >         + HTMLDocument.uid2url(uidIter.term().text()));
> > > > >       //delete the term from the reader
> > > > >       reader.delete(uidIter.term());
> > > > >       //go to the nextfield
> > > > >       uidIter.next();
> > > > >      }
> > > > >      Trace.TRACE("INDEXING INFO: Deleting Old Content Phase
> > > > > Completed");
> > > > >      //turn off the deleting flag
> > > > >      deleting = false;
> > > > >     }//close the deleting branch
> > > > >     //close the enummeration
> > > > >     uidIter.close(); // close uid iterator
> > > > >     //close the reader
> > > > >     reader.close(); // close existing index
> > > > >
> > > > >    }
> > > > >    //we go here is the index already existed
> > > > >    else {
> > > > >     Trace.TRACE("INDEXING INFO: Index Folder Did Not Exist.
> > > > > Start Creation
> > > > > Of
> > > > >  New Index");
> > > > >     // don't have exisiting
> > > > >     indexDocs(file);
> > > > >    }
> > > > >   }
> > > > >
> > > > >   private static void indexDocs(File file) throws Exception {
> > > > >    //check if we are at the top of a directory
> > > > >    if (file.isDirectory()) {
> > > > >     //get a list of the files
> > > > >     String[] files = file.list();
> > > > >     //sort them
> > > > >     Arrays.sort(files);
> > > > >     //index each file in the directory recursively
> > > > >     //we keep repeating this logic until we hit a
> > > > >     //file
> > > > >     for (int i = 0; i < files.length; i++)
> > > > >      //pass in the parent directory and the current file
> > > > >      //into the file constructor and index
> > > > >      indexDocs(new File(file, files[i]));
> > > > >
> > > > >    }
> > > > >    //we have an actual file, so we need to consider the
> > > > >    //file extensions so the correct Document is created
> > > > >    else if (file.getPath().endsWith(".html")
> > > > >      || file.getPath().endsWith(".htm")
> > > > >      || file.getPath().endsWith(".txt")
> > > > >      || file.getPath().endsWith(".doc")
> > > > >      || file.getPath().endsWith(".xml")
> > > > >      || file.getPath().endsWith(".pdf")) {
> > > > >
> > > > >     //if this is reached it means we were in the midst
> > > > >     //of an incremental update
> > > > >     if (uidIter != null) {
> > > > >      //get the uid for the document we are on
> > > > >      String uid = HTMLDocument.uid(file);
> > > > >      //now compare this document to the one we have in the
> > > > >      //enummeration of terms.
> > > > >      //if the term in the enummeration is less than the
> > > > >      //term we are on it must be deleted (if we are indeed
> > > > >      //doing an incrementatal update)
> > > > >      Trace.TRACE("INDEXING INFO: Beginnging Incremental
> update
> > > > >  comparisions");
> > > > >      while (uidIter.term() != null
> > > > >        && uidIter.term().field() == "uid"
> > > > >        && uidIter.term().text().compareTo(uid) < 0) {
> > > > >       //delete stale docs
> > > > >       if (deleting) {
> > > > >        reader.delete(uidIter.term());
> > > > >       }
> > > > >       uidIter.next();
> > > > >      }
> > > > >      //if the terms are equal there is no change with this
> > > > > document
> > > > >      //we keep it as is
> > > > >      if (uidIter.term() != null && uidIter.term().field()
==
> > > > > "uid"
> > > > >        && uidIter.term().text().compareTo(uid) == 0) {
> > > > >       uidIter.next();
> > > > >      }
> > > > >      //if we are not deleting and the document was not there
> > > > >      //it means we didn't have this document on the last
> index
> > > > >      //and we should add it
> > > > >      else if (!deleting) {
> > > > >       if (file.getPath().endsWith(".pdf")) {
> > > > >        Document doc = LucenePDFDocument.getDocument(file);
> > > > >        Trace.TRACE("INDEXING INFO: Adding new document to the
> > > > > existing
> > > > > index:
> > > > >  "
> > > > >            + doc.get("url"));
> > > > >        writer.addDocument(doc);
> > > > >       } else if (file.getPath().endsWith(".xml")) {
> > > > >        Document doc = XMLDocument.Document(file);
> > > > >        Trace.TRACE("INDEXING INFO: Adding new document to the
> > > > > existing
> > > > > index:
> > > > >  "
> > > > >            + doc.get("url"));
> > > > >        writer.addDocument(doc);
> > > > >       } else {
> > > > >        Document doc = HTMLDocument.Document(file);
> > > > >        Trace.TRACE("INDEXING INFO: Adding new document to the
> > > > > existing
> > > > > index:
> > > > >  "
> > > > >            + doc.get("url"));
> > > > >        writer.addDocument(doc);
> > > > >       }
> > > > >      }
> > > > >     }//end the if for an incremental update
> > > > >     //we are creating a new index, add all document types
> > > > >     else {
> > > > >      if (file.getPath().endsWith(".pdf")) {
> > > > >       Document doc = LucenePDFDocument.getDocument(file);
> > > > >       Trace.TRACE("INDEXING INFO: Adding a new document to
> the
> > > > > new index: "
> > > > >           + doc.get("url"));
> > > > >       writer.addDocument(doc);
> > > > >      } else if (file.getPath().endsWith(".xml")) {
> > > > >       Document doc = XMLDocument.Document(file);
> > > > >       Trace.TRACE("INDEXING INFO: Adding a new document to
> the
> > > > > new index: "
> > > > >           + doc.get("url"));
> > > > >       writer.addDocument(doc);
> > > > >      } else {
> > > > >       Document doc = HTMLDocument.Document(file);
> > > > >       Trace.TRACE("INDEXING INFO: Adding a new document to
> the
> > > > > new index: "
> > > > >           + doc.get("url"));
> > > > >       writer.addDocument(doc);
> > > > >      }//close the else
> > > > >     }//close the else for a new index
> > > > >    }//close the else if to handle file types
> > > > >   }//close the indexDocs method
> > > > >
> > > > >  }
> > > > >
> > > > >
> > > > >  ----- Original Message ----- 
> > > > >  From: "Craig McClanahan" <craigmcc@gmail.com
> > > > >  To: "Jakarta Commons Users List"
> > > > > <commons-user@jakarta.apache.org
> > > > >  Sent: Thursday, November 11, 2004 6:13 PM
> > > > >  Subject: Re: avoiding locking
> > > > >
> > > > >
> > > > >   In order to get any useful help, it would be nice to know
> > > > > what you are
> > > > >   trying to do, and (most importantly) what commons component
> > > > > is giving
> > > > >   you the problem :-).  The traditional approach is to put a
> > > > > prefix on
> > > > >   your subject line -- for commons package "foo" it would be:
> > > > >
> > > > >     [foo] avoiding locking
> > > > >
> > > > >   It's also generally helpful to see the entire stack trace,
> > > > > not just
> > > > >   the exception message itself.
> > > > >
> > > > >   Craig
> > > > >
> > > > >
> > > > >   On Thu, 11 Nov 2004 17:27:19 -0500, Luke Shannon
> > > > >   <lshannon@hypermedia.com wrote:
> > > > >    What can I do to avoid locking issues?
> > > > >
> > > > >    Unable to execute incremental update Lock obtain timed
> out:
> > > > >
> > > > >
> > > >
> > >
>
Lock@/usr/tomcat/jakarta-tomcat-5.0.19/temp/lucene-398fbd170a5457d05e2f4d432
> > > > >  10f7fe8-write.lock
> > > > >
> > > > >    Thanks,
> > > > >
> > > > >    Luke
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> ---------------------------------------------------------------------
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> > > > >   For additional commands, e-mail:
> > > > > commons-user-help@jakarta.apache.org
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> ---------------------------------------------------------------------
> > > > >  To unsubscribe, e-mail:
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> > > > >  For additional commands, e-mail:
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> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> ---------------------------------------------------------------------
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