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From Stu Hood <stuh...@gmail.com>
Subject Re: CASSANDRA-1472 (bitmap indexes)
Date Sun, 14 Nov 2010 00:34:46 GMT
> Is it worth testing 0.7-branch-without-1472 to make sure of that?
Dragos: if you have time, this would be helpful. If you already have a KEYS
index created, you shouldn't need to re-load the data, as the file format
hasn't changed.

Thanks,
Stu

On Sat, Nov 13, 2010 at 4:40 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> Is it worth testing 0.7-branch-without-1472 to make sure of that?
>
> On Fri, Nov 12, 2010 at 10:28 AM, Stu Hood <stuhood@gmail.com> wrote:
> > Great, thanks for the variable Dragos: I'm fairly sure I broke this in
> the
> > refactoring I did in 1472 to fit in a second index type.
> >
> >
> > On Fri, Nov 12, 2010 at 4:03 AM, dragos cernahoschi <
> > dragos.cernahoschi@gmail.com> wrote:
> >
> >> I confirm: the KEYS indexes have the same behavior as the KEYS_BITMAP
> >> indexes: time out/succeed on the same queries.
> >>
> >> By the way, the insert of my data set with KEYS_BITMAP is much faster
> than
> >> KEYS (about 5.5 times) and less gc intensive.
> >>
> >> Dragos
> >>
> >> On Tue, Nov 9, 2010 at 8:05 PM, Stu Hood <stu.hood@rackspace.com>
> wrote:
> >>
> >> > Interesting, thanks for the info.
> >> >
> >> > Perhaps the limitation is that index queries involving multiple
> clauses
> >> are
> >> > currently implemented using brute-force filtering rather than an index
> >> join?
> >> > The bitmap indexes have native support for this type of join, but it's
> >> not
> >> > being used yet.
> >> >
> >> > To confirm: have you tried the same scenario with KEYS indexes? They
> use
> >> > the same codepath for multiple index expressions, and should
> experience
> >> the
> >> > same timeouts. Also, can you rerun the KEYS_BITMAP test with DEBUG
> >> logging
> >> > enabled, to ensure that we aren't going into some kind of infinite
> loop?
> >> >
> >> > Thanks for the help,
> >> > Stu
> >> >
> >> > -----Original Message-----
> >> > From: "dragos cernahoschi" <dragos.cernahoschi@gmail.com>
> >> > Sent: Tuesday, November 9, 2010 11:50am
> >> > To: dev@cassandra.apache.org
> >> > Subject: Re: CASSANDRA-1472 (bitmap indexes)
> >> >
> >> > 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.hood@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.cernahoschi@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.hood@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.cernahoschi@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.hood@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.cernahoschi@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.
> >> > > > >
> >> > > > >
> >> > > > >
> >> > > >
> >> > > >
> >> > > >
> >> > >
> >> > >
> >> > >
> >> >
> >> >
> >> >
> >>
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>

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