Not using any secondary indicies and memtable_flush_queue_size is the default 4.
But let me tell you how data is "mutated" right now, maybe that will give you an insight on how this is happening Basically the frame data table has the following primary key: PRIMARY KEY ((id), trackid, "timestamp") Generally data is inserted once. So day to day writes are all new rows. However, when out process for generating analytics for these rows changes, we run the media back through again, causing overwrites. Up until last night, this was just a new insert because the PK never changed so it was always 1-to-1 overwrite of every row. Last night was the first time that a new change went in where the PK could actually change so now the process is always, DELETE by partition key, insert all rows for partition key, repeat. We two tables that have similar frame data projections and some other aggregates with much smaller row count per partition key. hope that helps, arne On Dec 16, 2014, at 2:46 PM, Ryan Svihla <rsvi...@datastax.com> wrote: > so you've got some blocked flush writers but you have a incredibly large > number of dropped mutations, are you using secondary indexes? and if so how > many? what is your flush queue set to? > > On Tue, Dec 16, 2014 at 4:43 PM, Arne Claassen <a...@emotient.com> wrote: > Of course QA decided to start a test batch (still relatively low traffic), so > I hope it doesn't throw the tpstats off too much > > Node 1: > Pool Name Active Pending Completed Blocked All > time blocked > MutationStage 0 0 13804928 0 > 0 > ReadStage 0 0 10975 0 > 0 > RequestResponseStage 0 0 7725378 0 > 0 > ReadRepairStage 0 0 1247 0 > 0 > ReplicateOnWriteStage 0 0 0 0 > 0 > MiscStage 0 0 0 0 > 0 > HintedHandoff 1 1 50 0 > 0 > FlushWriter 0 0 306 0 > 31 > MemoryMeter 0 0 719 0 > 0 > GossipStage 0 0 286505 0 > 0 > CacheCleanupExecutor 0 0 0 0 > 0 > InternalResponseStage 0 0 0 0 > 0 > CompactionExecutor 4 14 159 0 > 0 > ValidationExecutor 0 0 0 0 > 0 > MigrationStage 0 0 0 0 > 0 > commitlog_archiver 0 0 0 0 > 0 > AntiEntropyStage 0 0 0 0 > 0 > PendingRangeCalculator 0 0 11 0 > 0 > MemtablePostFlusher 0 0 1781 0 > 0 > > Message type Dropped > READ 0 > RANGE_SLICE 0 > _TRACE 0 > MUTATION 391041 > COUNTER_MUTATION 0 > BINARY 0 > REQUEST_RESPONSE 0 > PAGED_RANGE 0 > READ_REPAIR 0 > > Node 2: > Pool Name Active Pending Completed Blocked All > time blocked > MutationStage 0 0 997042 0 > 0 > ReadStage 0 0 2623 0 > 0 > RequestResponseStage 0 0 706650 0 > 0 > ReadRepairStage 0 0 275 0 > 0 > ReplicateOnWriteStage 0 0 0 0 > 0 > MiscStage 0 0 0 0 > 0 > HintedHandoff 2 2 12 0 > 0 > FlushWriter 0 0 37 0 > 4 > MemoryMeter 0 0 70 0 > 0 > GossipStage 0 0 14927 0 > 0 > CacheCleanupExecutor 0 0 0 0 > 0 > InternalResponseStage 0 0 0 0 > 0 > CompactionExecutor 4 7 94 0 > 0 > ValidationExecutor 0 0 0 0 > 0 > MigrationStage 0 0 0 0 > 0 > commitlog_archiver 0 0 0 0 > 0 > AntiEntropyStage 0 0 0 0 > 0 > PendingRangeCalculator 0 0 3 0 > 0 > MemtablePostFlusher 0 0 114 0 > 0 > > Message type Dropped > READ 0 > RANGE_SLICE 0 > _TRACE 0 > MUTATION 0 > COUNTER_MUTATION 0 > BINARY 0 > REQUEST_RESPONSE 0 > PAGED_RANGE 0 > READ_REPAIR 0 > > Node 3: > Pool Name Active Pending Completed Blocked All > time blocked > MutationStage 0 0 1539324 0 > 0 > ReadStage 0 0 2571 0 > 0 > RequestResponseStage 0 0 373300 0 > 0 > ReadRepairStage 0 0 325 0 > 0 > ReplicateOnWriteStage 0 0 0 0 > 0 > MiscStage 0 0 0 0 > 0 > HintedHandoff 1 1 21 0 > 0 > FlushWriter 0 0 38 0 > 5 > MemoryMeter 0 0 59 0 > 0 > GossipStage 0 0 21491 0 > 0 > CacheCleanupExecutor 0 0 0 0 > 0 > InternalResponseStage 0 0 0 0 > 0 > CompactionExecutor 4 9 85 0 > 0 > ValidationExecutor 0 0 0 0 > 0 > MigrationStage 0 0 0 0 > 0 > commitlog_archiver 0 0 0 0 > 0 > AntiEntropyStage 0 0 0 0 > 0 > PendingRangeCalculator 0 0 6 0 > 0 > MemtablePostFlusher 0 0 164 0 > 0 > > Message type Dropped > READ 0 > RANGE_SLICE 0 > _TRACE 0 > MUTATION 205259 > COUNTER_MUTATION 0 > BINARY 0 > REQUEST_RESPONSE 0 > PAGED_RANGE 0 > READ_REPAIR 18 > > > Compaction seems like the only thing consistently active and pending > > On Tue, Dec 16, 2014 at 2:18 PM, Ryan Svihla <rsvi...@datastax.com> wrote: > Ok based on those numbers I have a theory.. > > can you show me nodetool tptats for all 3 nodes? > > On Tue, Dec 16, 2014 at 4:04 PM, Arne Claassen <a...@emotient.com> wrote: > No problem with the follow up questions. I'm on a crash course here trying to > understand what makes C* tick so I appreciate all feedback. > > We reprocessed all media (1200 partition keys) last night where partition > keys had somewhere between 4k and 200k "rows". After that completed, no > traffic went to cluster at all for ~8 hours and throughout today, we may get > a couple (less than 10) queries per second and maybe 3-4 write batches per > hour. > > I assume the last value in the Partition Size histogram is the largest row: > > 20924300 bytes: 79 > 25109160 bytes: 57 > > The majority seems clustered around 200000 bytes. > > I will look at switching my inserts to unlogged batches since they are always > for one partition key. > > On Tue, Dec 16, 2014 at 1:47 PM, Ryan Svihla <rsvi...@datastax.com> wrote: > Can you define what is "virtual no traffic" sorry to be repetitive about > that, but I've worked on a lot of clusters in the past year and people have > wildly different ideas what that means. > > unlogged batches of the same partition key are definitely a performance > optimization. Typically async is much faster and easier on the cluster when > you're using multip partition key batches. > > nodetool cfhistograms <keyspace> <tablename> > > On Tue, Dec 16, 2014 at 3:42 PM, Arne Claassen <a...@emotient.com> wrote: > Actually not sure why the machine was originally configured at 6GB since we > even started it on an r3.large with 15GB. > > Re: Batches > > Not using batches. I actually have that as a separate question on the list. > Currently I fan out async single inserts and I'm wondering if batches are > better since my data is inherently inserted in blocks of ordered rows for a > single partition key. > > > Re: Traffic > > There isn't all that much traffic. Inserts come in as blocks per partition > key, but then can be 5k-200k rows for that partition key. Each of these rows > is less than 100k. It's small, lots of ordered rows. It's frame and sub-frame > information for media. and rows for one piece of media is inserted at once > (the partition key). > > For the last 12 hours, where the load on all these machine has been stuck > there's been virtually no traffic at all. This is the nodes basically sitting > idle, except that they had load of 4 each. > > BTW, how do you determine widest row or for that matter number of tombstones > in a row? > > thanks, > arne > > On Tue, Dec 16, 2014 at 1:24 PM, Ryan Svihla <rsvi...@datastax.com> wrote: > So 1024 is still a good 2.5 times what I'm suggesting, 6GB is hardly enough > to run Cassandra well in, especially if you're going full bore on loads. > However, you maybe just flat out be CPU bound on your write throughput, how > many TPS and what size writes do you have? Also what is your widest row? > > Final question what is compaction throughput at? > > > On Tue, Dec 16, 2014 at 3:20 PM, Arne Claassen <a...@emotient.com> wrote: > The starting configuration I had, which is still running on two of the nodes, > was 6GB Heap, 1024MB parnew which is close to what you are suggesting and > those have been pegged at load 4 for the over 12 hours with hardly and read > or write traffic. I will set one to 8GB/400MB and see if its load changes. > > On Tue, Dec 16, 2014 at 1:12 PM, Ryan Svihla <rsvi...@datastax.com> wrote: > So heap of that size without some tuning will create a number of problems > (high cpu usage one of them), I suggest either 8GB heap and 400mb parnew > (which I'd only set that low for that low cpu count) , or attempt the tunings > as indicated in https://issues.apache.org/jira/browse/CASSANDRA-8150 > > On Tue, Dec 16, 2014 at 3:06 PM, Arne Claassen <a...@emotient.com> wrote: > Changed the 15GB node to 25GB heap and the nice CPU is down to ~20% now. > Checked my dev cluster to see if the ParNew log entries are just par for the > course, but not seeing them there. However, both have the following every 30 > seconds: > > DEBUG [BatchlogTasks:1] 2014-12-16 21:00:44,898 BatchlogManager.java (line > 165) Started replayAllFailedBatches > DEBUG [MemtablePostFlusher:1] 2014-12-16 21:00:44,899 ColumnFamilyStore.java > (line 866) forceFlush requested but everything is clean in batchlog > DEBUG [BatchlogTasks:1] 2014-12-16 21:00:44,899 BatchlogManager.java (line > 200) Finished replayAllFailedBatches > > Is that just routine scheduled house-keeping or a sign of something else? > > On Tue, Dec 16, 2014 at 12:52 PM, Arne Claassen <a...@emotient.com> wrote: > Sorry, I meant 15GB heap on the one machine that has less nice CPU% now. The > others are 6GB > > On Tue, Dec 16, 2014 at 12:50 PM, Arne Claassen <a...@emotient.com> wrote: > AWS r3.xlarge, 30GB, but only using a Heap of 10GB, new 2GB because we might > go c3.2xlarge instead if CPU is more important than RAM > Storage is optimized EBS SSD (but iostat shows no real IO going on) > Each node only has about 10GB with ownership of 67%, 64.7% & 68.3%. > > The node on which I set the Heap to 10GB from 6GB the utlilization has > dropped to 46%nice now, but the ParNew log messages still continue at the > same pace. I'm gonna up the HEAP to 20GB for a bit, see if that brings that > nice CPU further down. > > No TombstoneOverflowingExceptions. > > On Tue, Dec 16, 2014 at 11:50 AM, Ryan Svihla <rsvi...@datastax.com> wrote: > What's CPU, RAM, Storage layer, and data density per node? Exact heap > settings would be nice. In the logs look for TombstoneOverflowingException > > > On Tue, Dec 16, 2014 at 1:36 PM, Arne Claassen <a...@emotient.com> wrote: > I'm running 2.0.10. > > The data is all time series data and as we change our pipeline, we've been > periodically been reprocessing the data sources, which causes each time > series to be overwritten, i.e. every row per partition key is deleted and > re-written, so I assume i've been collecting a bunch of tombstones. > > Also, the presence of the ever present and never completing compaction types, > i assumed were an artifact of tombstoning, but i fully admit to conjecture > based on about ~20 blog posts and stackoverflow questions i've surveyed. > > I doubled the Heap on one node and it changed nothing regarding the load or > the ParNew log statements. New Generation Usage is 50%, Eden itself is 56%. > > Anything else i should look at and report, let me know. > > On Tue, Dec 16, 2014 at 11:14 AM, Jonathan Lacefield > <jlacefi...@datastax.com> wrote: > Hello, > > What version of Cassandra are you running? > > If it's 2.0, we recently experienced something similar with 8447 [1], which > 8485 [2] should hopefully resolve. > > Please note that 8447 is not related to tombstones. Tombstone processing > can put a lot of pressure on the heap as well. Why do you think you have a > lot of tombstones in that one particular table? > > [1] https://issues.apache.org/jira/browse/CASSANDRA-8447 > [2] https://issues.apache.org/jira/browse/CASSANDRA-8485 > > Jonathan > > > Jonathan Lacefield > Solution Architect | (404) 822 3487 | jlacefi...@datastax.com > > > > On Tue, Dec 16, 2014 at 2:04 PM, Arne Claassen <a...@emotient.com> wrote: > I have a three node cluster that has been sitting at a load of 4 (for each > node), 100% CPI utilization (although 92% nice) for that last 12 hours, ever > since some significant writes finished. I'm trying to determine what tuning I > should be doing to get it out of this state. The debug log is just an endless > series of: > > DEBUG [ScheduledTasks:1] 2014-12-16 19:03:35,042 GCInspector.java (line 118) > GC for ParNew: 166 ms for 10 collections, 4400928736 used; max is 8000634880 > DEBUG [ScheduledTasks:1] 2014-12-16 19:03:36,043 GCInspector.java (line 118) > GC for ParNew: 165 ms for 10 collections, 4440011176 used; max is 8000634880 > DEBUG [ScheduledTasks:1] 2014-12-16 19:03:37,043 GCInspector.java (line 118) > GC for ParNew: 135 ms for 8 collections, 4402220568 used; max is 8000634880 > > iostat shows virtually no I/O. > > Compaction may enter into this, but i don't really know what to make of > compaction stats since they never change: > > [root@cassandra-37919c3a ~]# nodetool compactionstats > pending tasks: 10 > compaction type keyspace table completed > total unit progress > Compaction mediamedia_tracks_raw 271651482 > 563615497 bytes 48.20% > Compaction mediamedia_tracks_raw 30308910 > 21676695677 bytes 0.14% > Compaction mediamedia_tracks_raw 1198384080 > 1815603161 bytes 66.00% > Active compaction remaining time : 0h22m24s > > 5 minutes later: > > [root@cassandra-37919c3a ~]# nodetool compactionstats > pending tasks: 9 > compaction type keyspace table completed > total unit progress > Compaction mediamedia_tracks_raw 271651482 > 563615497 bytes 48.20% > Compaction mediamedia_tracks_raw 30308910 > 21676695677 bytes 0.14% > Compaction mediamedia_tracks_raw 1198384080 > 1815603161 bytes 66.00% > Active compaction remaining time : 0h22m24s > > Sure the pending tasks went down by one, but the rest is identical. > media_tracks_raw likely has a bunch of tombstones (can't figure out how to > get stats on that). > > Is this behavior something that indicates that i need more Heap, larger new > generation? Should I be manually running compaction on tables with lots of > tombstones? > > Any suggestions or places to educate myself better on performance tuning > would be appreciated. > > arne > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. > > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. > > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. > > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. > > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. > > > > -- > > Ryan Svihla > Solution Architect > > > > DataStax is the fastest, most scalable distributed database technology, > delivering Apache Cassandra to the world’s most innovative enterprises. > Datastax is built to be agile, always-on, and predictably scalable to any > size. With more than 500 customers in 45 countries, DataStax is the database > technology and transactional backbone of choice for the worlds most > innovative companies such as Netflix, Adobe, Intuit, and eBay. >
