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From Chip Salzenberg <c...@pobox.com>
Subject Re: 0.7.0beta2 with 128G memory = bizarre tiny files. help?
Date Wed, 27 Oct 2010 19:52:28 GMT
OK, after upgrading to "apache-cassandra-2010-10-27_12-30-38", here's
what "show keyspaces" says about the relevant keyspace:

    ColumnFamily: Standard1
      Columns sorted by: org.apache.cassandra.db.marshal.BytesType
      Row cache size / save period: 0.0/0
      Key cache size / save period: 200000.0/3600
      Memtable thresholds: 9.590625/2046/60
      GC grace seconds: 864000
      Compaction min/max thresholds: 4/32

I created it with "schematool import" off of the stock config in b2.


On 10/27/2010 11:36 AM, Jonathan Ellis wrote:
> Not in b2.
> On Oct 27, 2010 11:08 AM, "Chip Salzenberg" <chip@pobox.com> wrote:
>> Are these values available in JMX? If so, which ones are they? I'd
>> prefer not to possibly destroy the evidence by upgrading.
>>
>> On 10/27/2010 6:50 AM, Jonathan Ellis wrote:
>>> Connect with the cli and run "show keyspaces." It sounds like
>>> Cassandra somehow picked ludicrously low memtable thresholds. There
>>> will be a line like
>>>
>>> Memtable thresholds: 0.2953125/63/60
>>>
>>> This may not be in the b2 cli, in which case you will need to upgrade
>>> to the nightly from
>>>
> http://hudson.zones.apache.org/hudson/job/Cassandra/lastSuccessfulBuild/artifact/cassandra/build/
>>> (essentially the same as rc1 being voted on).
>>>
>>> On Wed, Oct 27, 2010 at 4:17 AM, Chip Salzenberg <chip@pobox.com> wrote:
>>>> I recently tested 0.7.0beta2 with good results on a reasonably powerful
>>>> machine: 8 Xeon cores (16 if you count hyperthreads), 64G memory, and
>>>> some nice HP RAID. So far so good. But when I took the same config and
>>>> moved it to a basically identical box with 128G of memory, cassandra
>>>> started responding to writes by creating a plethora of teeny tiny
>>>> sstables -- something it had not done before. For example:
>>>>
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:27,881 Memtable.java (line
>>>> 150) Writing Memtable-Standard1@950886315(651 bytes, 18 operations)
>>>> INFO [MUTATION_STAGE:8] 2010-10-27 01:53:27,882 ColumnFamilyStore.java
>>>> (line 459) switching in a fresh Memtable for Standard1 at
>>>>
> CommitLogContext(file='/var/lib/cassandra/commitlog/_chip/CommitLog-1288169534132.log',
>>>> position=27598)
>>>> INFO [MUTATION_STAGE:8] 2010-10-27 01:53:27,883 ColumnFamilyStore.java
>>>> (line 771) Enqueuing flush of Memtable-Standard1@1383310803(384 bytes,
>>>> 10 operations)
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:27,902 Memtable.java (line
>>>> 157) Completed flushing
>>>> /var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-7-Data.db
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:27,903 Memtable.java (line
>>>> 150) Writing Memtable-Standard1@996627145(360 bytes, 10 operations)
>>>> INFO [MUTATION_STAGE:3] 2010-10-27 01:53:27,927 ColumnFamilyStore.java
>>>> (line 459) switching in a fresh Memtable for Standard1 at
>>>>
> CommitLogContext(file='/var/lib/cassandra/commitlog/_chip/CommitLog-1288169534132.log',
>>>> position=31446)
>>>> INFO [MUTATION_STAGE:3] 2010-10-27 01:53:27,927 ColumnFamilyStore.java
>>>> (line 771) Enqueuing flush of Memtable-Standard1@1909350010(957 bytes,
>>>> 26 operations)
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:27,932 Memtable.java (line
>>>> 157) Completed flushing
>>>> /var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-8-Data.db
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:27,933 Memtable.java (line
>>>> 150) Writing Memtable-Standard1@1383310803(384 bytes, 10 operations)
>>>> INFO [CompactionExecutor:1] 2010-10-27 01:53:27,934
>>>> CompactionManager.java (line 233) Compacting
>>>>
> [org.apache.cassandra.io.sstable.SSTableReader(path='/var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-5-Data.db'),org.apache.cassandra.io.sstable.SSTableReader(path='/var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-6-Data.db'),org.apache.cassandra.io.sstable.SSTableReader(path='/var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-7-Data.db'),org.apache.cassandra.io.sstable.SSTableReader(path='/var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-8-Data.db')]
>>>> INFO [MUTATION_STAGE:17] 2010-10-27 01:53:27,936 ColumnFamilyStore.java
>>>> (line 459) switching in a fresh Memtable for Standard1 at
>>>>
> CommitLogContext(file='/var/lib/cassandra/commitlog/_chip/CommitLog-1288169534132.log',
>>>> position=33074)
>>>> INFO [MUTATION_STAGE:17] 2010-10-27 01:53:27,936 ColumnFamilyStore.java
>>>> (line 771) Enqueuing flush of Memtable-Standard1@595066677(396 bytes, 11
>>>> operations)
>>>> INFO [FLUSH-WRITER-POOL:1] 2010-10-27 01:53:28,037 Memtable.java (line
>>>> 157) Completed flushing
>>>> /var/lib/cassandra/data/_chip/Keyspace1/Standard1-e-9-Data.db
>>>>
>>>> I tried lowering the available memory reported by bin/cassandra:
>>>>
>>>> system_memory_in_mb=`free -m | awk '/Mem:/ {print $2}'`
>>>> [ "$system_memory_in_mb" -gt 65536 ] &&
>>>> system_memory_in_mb=65536 #<<<< new
>>>>
>>>> Didn't help. I also tried maually setting the max memtable sizes:
>>>>
>>>> binary_memtable_throughput_in_mb: 512
>>>> memtable_throughput_in_mb: 4096
>>>>
>>>> Didn't help.
>>>>
>>>> Help?
>>>>
>>>

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