Michael,
The exception only occurs when the writer commits. But but the IndexReader can
keep on reading.
The searches are performed by the IndexSearcher using the IndexReader.
My filesystem is ext2fs.
I give a few details below about the way I use them; the FNF exception occurs
in the "commitIndexWriter" method.
Thanks,
Tom
// both reader and writer and static
protected static IndexWriter mAdIndexWriter=null;
protected static IndexReader mAdIndexReader=null;
// misc
protected static IndexSearcher mAdIndexSearcher=null;
protected static Analyzer mAdIndexAnalyser=null;
// create the writer once
private void initIndexWriter() throws EncheromaxException {
Directory adIndexDir=null;
// Where is the index ?
String
indexLocation=mConfigProperties.getProperty(PropertiesEnum.ADVERTISEMENT_INDEX_LOCATION);
// Get the ad's analyser
Analyzer analyser = getAdvertisementIndexAnalyser();
// create the writer
if(mAdIndexWriter==null){
try{
adIndexDir=FSDirectory.getDirectory(indexLocation);
boolean isTheIndexNew=true;
mAdIndexWriter = new IndexWriter(adIndexDir,
analyser,isTheIndexNew,IndexWriter.MaxFieldLength. UNLIMITED) ;
/* ... */
}catch(Exception ex){
/*...*/
}
}
}
// get the reader
private IndexReader getAdvertisementIndexReader() throws EncheromaxException {
String indexLocation=null;
Directory adIndexDir=null;
// Where is the index ?
try{
indexLocation=mConfigProperties.getProperty(PropertiesEnum.ADVERTISEMENT_INDEX_LOCATION);
adIndexDir=FSDirectory.getDirectory(indexLocation);
}catch(Exception direx){
/*...*/
}
// create the reader if it doesn't exist yet
if(mAdIndexReader==null){
try{
mAdIndexReader= IndexReader.open(adIndexDir);
}catch(Exception ex){
/*..*/
}
}else{
try{
/* do we need to re-open it ? */
if(mAdIndexReader.isCurrent()==false){
// synchronize on the reader
synchronized(mAdIndexReader){
mAdIndexReader= IndexReader.open(adIndexDir);
}
}
}catch(Exception ioex){
/*...*/
throw new
EncheromaxException(CommonErrorEnum.INDEX_READER_CREATION_ERROR);
}
}
return mAdIndexReader;
}
// get the searcher when I want to search
private IndexSearcher getAdvertisementIndexSearcher() throws
EncheromaxException {
// create the searcher if it doesn't exist yet
try{
if(mAdIndexSearcher==null){
try{
mAdIndexSearcher= new
IndexSearcher(getAdvertisementIndexReader());
}catch(Exception ex){
/*...*/
}
}
else if(!mAdIndexSearcher.getIndexReader().isCurrent()){
synchronized(mAdIndexSearcher){
mAdIndexSearcher=new
IndexSearcher(getAdvertisementIndexReader());
}
}
}catch(Exception ioex){
/*...*/
}
return mAdIndexSearcher;
}
// whenever I need to commit
public synchronized void commitIndexWriter() throws EncheromaxException{
try{
mAdIndexWriter.commit();
}catch(Exception docex){
/* THE FILE NOT FOUND EXCEPTION OCCURS HERE */
}
}
// add a document
private void addADocument(Document adDoc) throws EncheromaxException{
try{
mAdIndexWriter.addDocument(adDoc, getAdvertisementIndexAnalyser());
commitIndexWriter();
}catch(Exception docex){
/*...*/
}
}
--- En date de : Ven 8.1.10, Michael McCandless <[email protected]> a
écrit :
De: Michael McCandless <[email protected]>
Objet: Re: Concurrent access IndexReader / IndexWriter - FileNotFoundException
À: [email protected]
Date: Vendredi 8 Janvier 2010, 13h00
Normally, this (using an IndexReader, [re-]opening a new IndexReader
while an IndexWriter is committing) is perfectly fine. The reader
searches the point-in-time snapshot of the index as of when it was
opened.
But: what filesystem are you using? NFS presents challenges, for example.
Mike
On Fri, Jan 8, 2010 at 5:35 AM, legrand thomas <[email protected]> wrote:
> Hi,
>
> I often get a FileNotFoundException when my single IndexWriter commits while
> the IndexReader also tries to read. My application is multithreaded (Tomcat
> uses the business APIs); I firstly thought the read/write access was
> thread-safe but I probably forget something.
>
> Please help me to understand my mistakes:
>
> - When should I close the IndexWriter ? Each time I add/update a document or
> never ?
> - Should my java commit/read methods be synchronized ?
> - Should I lock the directory and what's the best way to do it ?
>
> I referred to the Lucene FAQ ("why do I sometimes get a FileNotFoundException
> when I search and update my index at the same time?") but I did not disable
> any locking for processes searching or updating the index.
>
> I use lucene-2.4.1.
>
> Thanks in advance,
> Tom
>
>
>
>
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