> Wide rows? How wide? How many rows per partition, typically and at the
> extreme? how many clustering columns?
Yes, wide rows with deletions of old data.
Number of keys (estimate): 909428
How I can calculate rows per partition via nodetool/jmx?
~ From 100 to 5,000,000.
I know its anti-pattern - cyclic buffer / queue.
But problems begins when we start adding new nodes to cluster - old & new nodes
do compactions.
DroppableTombstoneRatio: 5 - 6.5
TombstonesPerSlice: 0
CREATE TABLE home_timeline (
uid blob,
tuuid timeuuid,
cid text,
cuid blob,
PRIMARY KEY (uid, tuuid)
) WITH CLUSTERING ORDER BY (tuuid ASC)
AND bloom_filter_fp_chance = 0.1
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND compaction = {'sstable_size_in_mb': '160', 'class':
'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'}
AND compression = {'sstable_compression':
'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.0
AND default_time_to_live = 0
AND gc_grace_seconds = 86400
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.1
AND speculative_retry = '99.0PERCENTILE';
But we query this table with ORDER BY tuuid DESC. Could this be a problem?
> When you restart the node does it revert to completely normal response?
Yes it does.
> Which release of Cassandra?
Cassandra 2.1.13
> Does every node eventually hit this problem?
Yes, almost all.
> After a restart, how long before the problem recurs for that node?
Sometimes it occurred after 5 minutes after restart, sometimes it was 4 hours.
> On 12 Feb 2016, at 23:20, Jack Krupansky <[email protected]> wrote:
>
> Wide rows? How wide? How many rows per partition, typically and at the
> extreme? how many clustering columns?
>
> When you restart the node does it revert to completely normal response?
>
> Which release of Cassandra?
>
> Does every node eventually hit this problem?
>
> After a restart, how long before the problem recurs for that node?
>
> -- Jack Krupansky
>
> On Fri, Feb 12, 2016 at 4:06 AM, Skvazh Roman <[email protected]
> <mailto:[email protected]>> wrote:
> Hello!
> We have a cluster of 25 c3.4xlarge nodes (16 cores, 32 GiB) with attached 1.5
> TB 4000 PIOPS EBS drive.
> Sometimes one or two nodes user cpu spikes to 100%, load average to 20-30 -
> read requests drops of.
> Only restart of this cassandra services helps.
> Please advice.
>
> One big table with wide rows. 600 Gb per node.
> LZ4Compressor
> LeveledCompaction
>
> concurrent compactors: 4
> compactor throughput: tried from 16 to 128
> Concurrent_readers: from 16 to 32
> Concurrent_writers: 128
>
>
> https://gist.github.com/rskvazh/de916327779b98a437a6
> <https://gist.github.com/rskvazh/de916327779b98a437a6>
>
>
> JvmTop 0.8.0 alpha - 06:51:10, amd64, 16 cpus, Linux 3.14.44-3, load avg
> 19.35
> http://code.google.com/p/jvmtop <http://code.google.com/p/jvmtop>
>
> Profiling PID 9256: org.apache.cassandra.service.CassandraDa
>
> 95.73% ( 4.31s)
> ....google.common.collect.AbstractIterator.tryToComputeN()
> 1.39% ( 0.06s) com.google.common.base.Objects.hashCode()
> 1.26% ( 0.06s) io.netty.channel.epoll.Native.epollWait()
> 0.85% ( 0.04s) net.jpountz.lz4.LZ4JNI.LZ4_compress_limitedOutput()
> 0.46% ( 0.02s) net.jpountz.lz4.LZ4JNI.LZ4_decompress_fast()
> 0.26% ( 0.01s) com.google.common.collect.Iterators$7.computeNext()
> 0.06% ( 0.00s) io.netty.channel.epoll.Native.eventFdWrite()
>
>
> ttop:
>
> 2016-02-12T08:20:25.605+0000 Process summary
> process cpu=1565.15%
> application cpu=1314.48% (user=1354.48% sys=-40.00%)
> other: cpu=250.67%
> heap allocation rate 146mb/s
> [000405] user=76.25% sys=-0.54% alloc= 0b/s - SharedPool-Worker-9
> [000457] user=75.54% sys=-1.26% alloc= 0b/s - SharedPool-Worker-14
> [000451] user=73.52% sys= 0.29% alloc= 0b/s - SharedPool-Worker-16
> [000311] user=76.45% sys=-2.99% alloc= 0b/s - SharedPool-Worker-4
> [000389] user=70.69% sys= 2.62% alloc= 0b/s - SharedPool-Worker-6
> [000388] user=86.95% sys=-14.28% alloc= 0b/s - SharedPool-Worker-5
> [000404] user=70.69% sys= 0.10% alloc= 0b/s - SharedPool-Worker-8
> [000390] user=72.61% sys=-1.82% alloc= 0b/s - SharedPool-Worker-7
> [000255] user=87.86% sys=-17.87% alloc= 0b/s - SharedPool-Worker-1
> [000444] user=72.21% sys=-2.30% alloc= 0b/s - SharedPool-Worker-12
> [000310] user=71.50% sys=-2.31% alloc= 0b/s - SharedPool-Worker-3
> [000445] user=69.68% sys=-0.83% alloc= 0b/s - SharedPool-Worker-13
> [000406] user=72.61% sys=-4.40% alloc= 0b/s - SharedPool-Worker-10
> [000446] user=69.78% sys=-1.65% alloc= 0b/s - SharedPool-Worker-11
> [000452] user=66.86% sys= 0.22% alloc= 0b/s - SharedPool-Worker-15
> [000256] user=69.08% sys=-2.42% alloc= 0b/s - SharedPool-Worker-2
> [004496] user=29.99% sys= 0.59% alloc= 30mb/s - CompactionExecutor:15
> [004906] user=29.49% sys= 0.74% alloc= 39mb/s - CompactionExecutor:16
> [010143] user=28.58% sys= 0.25% alloc= 26mb/s - CompactionExecutor:17
> [000785] user=27.87% sys= 0.70% alloc= 38mb/s - CompactionExecutor:12
> [012723] user= 9.09% sys= 2.46% alloc= 2977kb/s - RMI TCP
> Connection(2673)-127.0.0.1
> [000555] user= 5.35% sys=-0.08% alloc= 474kb/s - SharedPool-Worker-24
> [000560] user= 3.94% sys= 0.07% alloc= 434kb/s - SharedPool-Worker-22
> [000557] user= 3.94% sys=-0.17% alloc= 339kb/s - SharedPool-Worker-25
> [000447] user= 2.73% sys= 0.60% alloc= 436kb/s - SharedPool-Worker-19
> [000563] user= 3.33% sys=-0.04% alloc= 460kb/s - SharedPool-Worker-20
> [000448] user= 2.73% sys= 0.27% alloc= 414kb/s - SharedPool-Worker-21
> [000554] user= 1.72% sys= 0.70% alloc= 232kb/s - SharedPool-Worker-26
> [000558] user= 1.41% sys= 0.39% alloc= 213kb/s - SharedPool-Worker-23
> [000450] user= 1.41% sys=-0.03% alloc= 158kb/s - SharedPool-Worker-17
>
