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) > >>> > >>> > > >>> > >>> > >>> > >> > >>> > >> > >>> > > > >>> > > >>> > >> > >> > > >
