Just one more observation here... Even if readerPooling is set to true, lucene has 2 readers (One for search & one updates/deletes)
But the reader for updates/deletes is not opened/closed for every commit call which is the default behavior as of today. It is opened only once (During first update/delete call) On Wed, Jun 1, 2016 at 3:10 PM, Ravikumar Govindarajan < [email protected]> wrote: > In newer versions of the code there are multiple streams involved. One for >> each open file handle plus if a sequential read is detected a new stream >> is >> created for the instance for better performance > > > Great. We just patched up our Blur version with this code. > > While I was digging at the reader-closed issue, was quite surprised to > observe the following behavior > > - Issue a commit > - Lucene opens a new reader via IndexWriter. (Doesn't re-use our > already opened DirectoryReader) > - Processes all updates/deletes/merges > - Closes the new reader > - Complete commit > > For a big index & lots of commits, opening a new-reader for every commit > is prohibitively expensive. > > > Here is the JIRA for it... > https://issues.apache.org/jira/browse/LUCENE-2297 > > All we need to do is just set "readerPooling=true" in IndexWriterConfig > class > > Please do explore this option when you find time. > > -- > Ravi > > > > On Tue, May 24, 2016 at 7:48 PM, Aaron McCurry <[email protected]> wrote: > >> On Tue, May 24, 2016 at 6:06 AM, Ravikumar Govindarajan < >> [email protected]> wrote: >> >> > We have solved it temporarily by using a KeepLastTwoCommits del policy. >> We >> > don't get these exceptions now!!! >> > >> >> Great! >> >> >> > >> > Btw, I see that pread calls in FSDataInputStream.java are synchronized. >> Is >> > it possible that merge DFS read calls could potentially block search DFS >> > read calls? >> > >> >> Yes. >> >> >> > >> > Would it be a good idea to have 2 DFSInputStreams for every file, one >> for >> > merge & another for search? >> > >> >> In newer versions of the code there are multiple streams involved. One >> for >> each open file handle plus if a sequential read is detected a new stream >> is >> created for the instance for better performance. Checkout the >> HdfsDirectory class. >> >> Aaron >> >> >> > >> > On Tue, May 10, 2016 at 7:43 PM, Ravikumar Govindarajan < >> > [email protected]> wrote: >> > >> > > Sorry, I mis-understood the code. >> > > I see that it has 2 locks IndexRefreshWriteLock & >> IndexRefreshReadLock. >> > > They look to be separate >> > > >> > > On Tue, May 10, 2016 at 7:16 PM, Ravikumar Govindarajan < >> > > [email protected]> wrote: >> > > >> > >> Thanks a lot Aaron. >> > >> >> > >> I guess we took a commit of 0.2.2 that doesn't have the >> > >> IndexRefreshWriteLock (IRWL). It looks like it co-ordinates between >> > >> searches & incoming mutation commits. If so, then it will likely >> solve >> > the >> > >> first issue for us (AlreadyClosedException) >> > >> >> > >> >> > >> Can you recollect if that was the reason IRWL was introduced? >> > >> >> > >> On Tue, May 10, 2016 at 6:40 PM, Aaron McCurry <[email protected]> >> > >> wrote: >> > >> >> > >>> On Tue, May 10, 2016 at 2:30 AM, Ravikumar Govindarajan < >> > >>> [email protected]> wrote: >> > >>> >> > >>> > Actually there are 2 issues... >> > >>> > >> > >>> > 1. IndexReaderClosedException >> > >>> > 2. HDFS Stream Closed >> > >>> > >> > >>> >> > >>> Likely when the index is closed it closes the underlying >> indexinputs as >> > >>> well causing the HDFS Stream closed exception. >> > >>> >> > >>> >> > >>> > >> > >>> > Merge completion results in File Deletion & ultimately HDFS Stream >> > >>> Closed >> > >>> > during Search.... >> > >>> > >> > >>> > I use IndexFileDeleter with KeepOnlyLastCommitDeletionPolicy. This >> > >>> blindly >> > >>> > deletes the file, without bothering to cross-check >> > >>> IndexReader.RefCount > >> > >>> > 0. >> > >>> > >> > >>> >> > >>> Hmm. You can see here: >> > >>> >> > >>> >> > >>> >> > >> https://github.com/apache/incubator-blur/blob/release-0.2.2-incubating/blur-core/src/main/java/org/apache/blur/manager/writer/BlurIndexSimpleWriter.java#L303 >> > >>> >> > >>> That once the new index is available it is swapped into the index >> ref >> > >>> object and the old one is sent to the index closer. Once the ref to >> > the >> > >>> index are low enough it closes the index. Or at least it should. >> > >>> >> > >>> I will continue looking into the problem but I don't have a solution >> > for >> > >>> you yet. >> > >>> >> > >>> Aaron >> > >>> >> > >>> >> > >>> >> > >>> > >> > >>> > >> > >>> > *Exception(message:Unknown error during rewrite, >> > >>> > stackTraceStr:java.io.IOException: Stream closed* >> > >>> > at >> > >>> >> org.apache.hadoop.hdfs.DFSInputStream.pread(DFSInputStream.java:1385) >> > >>> > at >> > org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:1374) >> > >>> > at >> > >>> >> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:89) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.hdfs.HdfsIndexInput.readInternal(HdfsIndexInput.java:62) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.buffer.ReusedBufferedIndexInput.readBytes(ReusedBufferedIndexInput.java:167) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.buffer.ReusedBufferedIndexInput.readBytes(ReusedBufferedIndexInput.java:122) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.hdfs.MmapCacheIndexInput.readAndcache(MmapCacheIndexInput.java:24) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.blockcache_v2.CacheIndexInput.fillNormally(CacheIndexInput.java:354) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.blockcache_v2.CacheIndexInput.fill(CacheIndexInput.java:379) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.blockcache_v2.CacheIndexInput.tryToFill(CacheIndexInput.java:297) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.store.blockcache_v2.CacheIndexInput.readByte(CacheIndexInput.java:151) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.lucene.warmup.TraceableIndexInput.readByte(TraceableIndexInput.java:62) >> > >>> > at org.apache.lucene.store.DataInput.readVInt(DataInput.java:108) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.lucene.codecs.BlockTreeTermsReader$FieldReader$SegmentTermsEnum$Frame.loadBlock(BlockTreeTermsReader.java:2366) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.lucene.codecs.BlockTreeTermsReader$FieldReader$SegmentTermsEnum.seekCeil(BlockTreeTermsReader.java:1949) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.blur.index.ExitableReader$ExitableTermsEnum.seekCeil(ExitableReader.java:250) >> > >>> > at >> > >>> > >> > >>> >> > >> org.apache.lucene.index.FilteredTermsEnum.next(FilteredTermsEnum.java:225) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.lucene.search.TermCollectingRewrite.collectTerms(TermCollectingRewrite.java:78) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.lucene.search.ConstantScoreAutoRewrite.rewrite(ConstantScoreAutoRewrite.java:95) >> > >>> > at >> > >>> > >> > >>> > >> > >>> >> > >> org.apache.lucene.search.MultiTermQuery$ConstantScoreAutoRewrite.rewrite(MultiTermQuery.java:220) >> > >>> > at >> > >>> >> > org.apache.lucene.search.MultiTermQuery.rewrite(MultiTermQuery.java:288) >> > >>> > at >> > org.apache.lucene.search.BooleanQuery.rewrite(BooleanQuery.java:412) >> > >>> > at >> > org.apache.lucene.search.BooleanQuery.rewrite(BooleanQuery.java:412) >> > >>> > at >> > org.apache.lucene.search.BooleanQuery.rewrite(BooleanQuery.java:412) >> > >>> > at >> > >>> > >> > >>> > On Mon, May 9, 2016 at 4:42 PM, Ravikumar Govindarajan < >> > >>> > [email protected]> wrote: >> > >>> > >> > >>> > > One extra info we gleaned from the logs... >> > >>> > > >> > >>> > > 1. Merge Starts & is about to complete >> > >>> > > 2. Searcher is opened >> > >>> > > 3. Merge Completes >> > >>> > > 4. Ref-count drops to 0 in IndexReader >> > >>> > > 5. IndexReader closed while Searcher is still open >> > >>> > > >> > >>> > > This seems to be the main pattern for causing the Exception >> > >>> > > >> > >>> > > -- >> > >>> > > Ravi >> > >>> > > >> > >>> > > On Mon, May 9, 2016 at 3:08 PM, Ravikumar Govindarajan < >> > >>> > > [email protected]> wrote: >> > >>> > > >> > >>> > >> Thanks Aaron... >> > >>> > >> >> > >>> > >> Just a quick question. Lucene itself has ref-counting to close >> > it's >> > >>> > >> readers no? Or Blur has it's own logic to handle it? >> > >>> > >> >> > >>> > >> -- >> > >>> > >> Ravi >> > >>> > >> >> > >>> > >> On Fri, May 6, 2016 at 7:56 PM, Aaron McCurry < >> [email protected] >> > > >> > >>> > wrote: >> > >>> > >> >> > >>> > >>> Likely yes. If have a few minutes this weekend I can look >> > through >> > >>> that >> > >>> > >>> version and see if I can point you in the right direction. >> > >>> > >>> >> > >>> > >>> On Fri, May 6, 2016 at 8:46 AM, Ravikumar Govindarajan < >> > >>> > >>> [email protected]> wrote: >> > >>> > >>> >> > >>> > >>> > Sometimes during an ongoing search we receive an >> > >>> > >>> > IndexReaderClosedException... >> > >>> > >>> > >> > >>> > >>> > We are on an older version of Blur (0.2.2). Has this been >> fixed >> > >>> in >> > >>> > >>> newer >> > >>> > >>> > versions or we have been using it wrongly? >> > >>> > >>> > >> > >>> > >>> > >> *stackTraceStr:org.apache.lucene.store.AlreadyClosedException: >> > >>> this >> > >>> > >>> > IndexReader cannot be used anymore as one of its child >> readers >> > >>> was >> > >>> > >>> closed* >> > >>> > >>> > at >> > >>> > >> org.apache.lucene.index.IndexReader.ensureOpen(IndexReader.java:257) >> > >>> > >>> > at >> > >>> > >>> > >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> > >>> >> > >> org.apache.lucene.index.FilterAtomicReader.fields(FilterAtomicReader.java:380) >> > >>> > >>> > at >> > >>> > >>> > >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> > >>> >> > >> org.apache.blur.index.ExitableReader$ExitableFilterAtomicReader.fields(ExitableReader.java:81) >> > >>> > >>> > at >> > >>> > >>> > >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> > >>> >> > >> org.apache.lucene.search.TermCollectingRewrite.collectTerms(TermCollectingRewrite.java:52) >> > >>> > >>> > at >> > >>> > >>> > >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> > >>> >> > >> org.apache.lucene.search.ConstantScoreAutoRewrite.rewrite(ConstantScoreAutoRewrite.java:95) >> > >>> > >>> > at >> > >>> > >>> > >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> > >>> >> > >> org.apache.lucene.search.MultiTermQuery$ConstantScoreAutoRewrite.rewrite(MultiTermQuery.java:220) >> > >>> > >>> > at >> > >>> > >>> >> > >>> > >> > >>> >> > org.apache.lucene.search.MultiTermQuery.rewrite(MultiTermQuery.java:288) >> > >>> > >>> > at >> > >>> > >> org.apache.lucene.search.BooleanQuery.rewrite(BooleanQuery.java:412) >> > >>> > >>> > >> > >>> > >>> >> > >>> > >> >> > >>> > >> >> > >>> > > >> > >>> > >> > >>> >> > >> >> > >> >> > > >> > >> > >
