I'm running the query on three columns with cardinalities: 22, 17 and 10. Interesting, if combining columns with cardinalities:
22 + 17 => no exception 22 + 10 => no exception 10 + 17 => timed out exception 22 + 17 + 10 => timed out exception On Tue, Nov 9, 2010 at 6:29 PM, Stu Hood <stu.h...@rackspace.com> wrote: > Can you tell me a little bit about your key distribution? How many unique > values are indexed (the cardinality)? > > Until the OrBiC projection I mention on 1472 is implemented, the bitmap > secondary indexes will perform terribly for high cardinality datasets. > > Thanks! > > > -----Original Message----- > From: "dragos cernahoschi" <dragos.cernahos...@gmail.com> > Sent: Tuesday, November 9, 2010 10:14am > To: dev@cassandra.apache.org > Subject: Re: CASSANDRA-1472 (bitmap indexes) > > Meantime the number of SSTable(s) reduced to just 7. Initially the > compaction thread suffered the same problem of "too many open files" and > couldn't do any compaction. > > But I'm still not able to run my tests: TimedOutException :( > > On Tue, Nov 9, 2010 at 5:51 PM, Stu Hood <stu.h...@rackspace.com> wrote: > > > Hmm, 500 sstables is definitely a degenerate case: did you disable > > compaction? By default, Cassandra strives to keep the sstable count below > > ~32, since accesses to separate sstables require seeks. > > > > In this case, the query will seek 500 times to check the secondary index > > for each sstable: if it finds matches it will need to seek to find them > in > > the primary index, and seek again for the data file. > > > > -----Original Message----- > > From: "dragos cernahoschi" <dragos.cernahos...@gmail.com> > > Sent: Tuesday, November 9, 2010 5:33am > > To: dev@cassandra.apache.org > > Subject: Re: CASSANDRA-1472 (bitmap indexes) > > > > There are about 500 SSTables (12GB of data including index data, > > statistics...) The source data file had about 3GB/26 million rows. > > > > I only test with EQ expressions for now. > > > > Increasing the file limit resolved the problem, but now I'm getting > > TimedOutException(s) from thrift when "querying" even with slice size of > 1. > > Is my machine too small (core 2 duo 2.93 2GB RAM Ubuntu 10.04) for such a > > test? > > > > I really have some interesting sets of data to test indexes with and I > want > > to make a comparison between ordinary indexes and bitmap indexes. > > > > Thank you, > > Dragos > > > > On Mon, Nov 8, 2010 at 6:42 PM, Stu Hood <stu.h...@rackspace.com> wrote: > > > > > Dragos, > > > > > > How many SSTables did you have on disk, and were any of your index > > > expressions GT(E)/LT(E)? > > > > > > I expect that you are bumping into a limitation of the current > > > implementation: it opens up to 128 file-handles per SSTable in the > worst > > > case for a GT/LT query (one per index bucket). > > > > > > A future version might remove that requirement, but for now, you should > > > probably bump the file handle limit on your machine to at least 2^16. > > > > > > Thanks, > > > Stu > > > > > > > > > -----Original Message----- > > > From: "dragos cernahoschi" <dragos.cernahos...@gmail.com> > > > Sent: Monday, November 8, 2010 10:05am > > > To: dev@cassandra.apache.org > > > Subject: CASSANDRA-1472 (bitmap indexes) > > > > > > Hi, > > > > > > I've got an exception during the following test: > > > > > > test machine: core 2 duo 2.93 2GB RAM Ubuntu 10.04 > > > > > > test scenario: > > > - 1 column family > > > - about 15 columns > > > - 7 indexed columns (bitmap) > > > - 26 million rows (insert operation went fine) > > > - thrift "query" on 3 of the indexed columns with get_indexed_slices > > > (count: > > > 100) > > > - got the following exception: > > > > > > 10/11/08 17:52:40 ERROR service.AbstractCassandraDaemon: Fatal > exception > > in > > > thread Thread[ReadStage:3,5,main] > > > java.io.IOError: java.io.FileNotFoundException: > > > /home/dragos/cassandra/data/keyspace/visit-e-814-4-Bitidx.db (Too many > > open > > > files) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.bitidx.SegmentIterator.open(SegmentIterator.java:78) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.bitidx.BitmapIndexReader.openBin(BitmapIndexReader.java:226) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.bitidx.BitmapIndexReader.iterator(BitmapIndexReader.java:214) > > > at > > > > > > org.apache.cassandra.io.sstable.SSTableReader.scan(SSTableReader.java:523) > > > at > > > > > > > > > org.apache.cassandra.db.secindex.KeysBitmapIndex.iterator(KeysBitmapIndex.java:103) > > > at > > > > > > org.apache.cassandra.db.ColumnFamilyStore.scan(ColumnFamilyStore.java:1371) > > > at > > > > > > > > > org.apache.cassandra.service.IndexScanVerbHandler.doVerb(IndexScanVerbHandler.java:41) > > > at > > > > > > > > > org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:51) > > > at > > > > > > > > > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) > > > at > > > > > > > > > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) > > > at java.lang.Thread.run(Thread.java:662) > > > Caused by: java.io.FileNotFoundException: > > > /home/dragos/cassandra/data/keyspace/visit-e-814-4-Bitidx.db (Too many > > open > > > files) > > > at java.io.FileInputStream.open(Native Method) > > > at java.io.FileInputStream.<init>(FileInputStream.java:106) > > > at > > > > org.apache.avro.file.SeekableFileInput.<init>(SeekableFileInput.java:29) > > > at > org.apache.avro.file.DataFileReader.<init>(DataFileReader.java:38) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.bitidx.SegmentIterator.open(SegmentIterator.java:72) > > > ... 10 more > > > 10/11/08 17:52:40 ERROR service.AbstractCassandraDaemon: Fatal > exception > > in > > > thread Thread[ReadStage:2,5,main] > > > java.io.IOError: java.io.FileNotFoundException: > > > /home/dragos/cassandra/data/keyspace/visit-e-1018-Index.db (Too many > open > > > files) > > > at > > > > > > > > > org.apache.cassandra.io.util.BufferedSegmentedFile.getSegment(BufferedSegmentedFile.java:68) > > > at > > > > > > > > > org.apache.cassandra.io.util.SegmentedFile$SegmentIterator.next(SegmentedFile.java:129) > > > at > > > > > > > > > org.apache.cassandra.io.util.SegmentedFile$SegmentIterator.next(SegmentedFile.java:1) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.SSTableReader.getPosition(SSTableReader.java:455) > > > at > > > > > > > > > org.apache.cassandra.io.sstable.SSTableReader.getFileDataInput(SSTableReader.java:572) > > > at > > > > > > > > > org.apache.cassandra.db.columniterator.SSTableSliceIterator.<init>(SSTableSliceIterator.java:49) > > > at > > > > > > > > > org.apache.cassandra.db.filter.SliceQueryFilter.getSSTableColumnIterator(SliceQueryFilter.java:72) > > > at > > > > > > > > > org.apache.cassandra.db.filter.QueryFilter.getSSTableColumnIterator(QueryFilter.java:84) > > > at > > > > > > > > > org.apache.cassandra.db.ColumnFamilyStore.getTopLevelColumns(ColumnFamilyStore.java:1190) > > > at > > > > > > > > > org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1082) > > > at > > > > > > > > > org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1052) > > > at > > > > > > org.apache.cassandra.db.ColumnFamilyStore.scan(ColumnFamilyStore.java:1378) > > > at > > > > > > > > > org.apache.cassandra.service.IndexScanVerbHandler.doVerb(IndexScanVerbHandler.java:41) > > > at > > > > > > > > > org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:51) > > > at > > > > > > > > > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) > > > at > > > > > > > > > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) > > > at java.lang.Thread.run(Thread.java:662) > > > Caused by: java.io.FileNotFoundException: > > > /home/dragos/cassandra/data/keyspace/visit-e-1018-Index.db (Too many > open > > > files) > > > at java.io.RandomAccessFile.open(Native Method) > > > at java.io.RandomAccessFile.<init>(RandomAccessFile.java:212) > > > at java.io.RandomAccessFile.<init>(RandomAccessFile.java:98) > > > at > > > > > > > > > org.apache.cassandra.io.util.BufferedRandomAccessFile.<init>(BufferedRandomAccessFile.java:142) > > > at > > > > > > > > > org.apache.cassandra.io.util.BufferedSegmentedFile.getSegment(BufferedSegmentedFile.java:62) > > > ... 16 more > > > > > > The same test worked fine with 1 million rows. > > > > > > > > > > > > > > > > > >
