Hi Sebastian, Thanks for your response.
No swap is used. No offense, I just don't see a reason why having swap would be the issue here. I put swapiness on 1. I also have jna installed. That should prevent java being swapped out as wel AFAIK. 2015-11-10 19:50 GMT+01:00 Sebastian Estevez <sebastian.este...@datastax.com >: > Turn off Swap. > > > http://docs.datastax.com/en/cassandra/2.1/cassandra/install/installRecommendSettings.html?scroll=reference_ds_sxl_gf3_2k__disable-swap > > > All the best, > > > [image: datastax_logo.png] <http://www.datastax.com/> > > Sebastián Estévez > > Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com > > [image: linkedin.png] <https://www.linkedin.com/company/datastax> [image: > facebook.png] <https://www.facebook.com/datastax> [image: twitter.png] > <https://twitter.com/datastax> [image: g+.png] > <https://plus.google.com/+Datastax/about> > <http://feeds.feedburner.com/datastax> > <http://goog_410786983> > > > <http://www.datastax.com/gartner-magic-quadrant-odbms> > > 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. > > On Tue, Nov 10, 2015 at 1:48 PM, PenguinWhispererThe . < > th3penguinwhispe...@gmail.com> wrote: > >> I also have the following memory usage: >> [root@US-BILLINGDSX4 cassandra]# free -m >> total used free shared buffers cached >> Mem: 12024 9455 2569 0 110 2163 >> -/+ buffers/cache: 7180 4844 >> Swap: 2047 0 2047 >> >> Still a lot free and a lot of free buffers/cache. >> >> 2015-11-10 19:45 GMT+01:00 PenguinWhispererThe . < >> th3penguinwhispe...@gmail.com>: >> >>> Still stuck with this. However I enabled GC logging. This shows the >>> following: >>> >>> [root@myhost cassandra]# tail -f gc-1447180680.log >>> 2015-11-10T18:41:45.516+0000: 225.428: [GC 2721842K->2066508K(6209536K), >>> 0.0199040 secs] >>> 2015-11-10T18:41:45.977+0000: 225.889: [GC 2721868K->2066511K(6209536K), >>> 0.0221910 secs] >>> 2015-11-10T18:41:46.437+0000: 226.349: [GC 2721871K->2066524K(6209536K), >>> 0.0222140 secs] >>> 2015-11-10T18:41:46.897+0000: 226.809: [GC 2721884K->2066539K(6209536K), >>> 0.0224140 secs] >>> 2015-11-10T18:41:47.359+0000: 227.271: [GC 2721899K->2066538K(6209536K), >>> 0.0302520 secs] >>> 2015-11-10T18:41:47.821+0000: 227.733: [GC 2721898K->2066557K(6209536K), >>> 0.0280530 secs] >>> 2015-11-10T18:41:48.293+0000: 228.205: [GC 2721917K->2066571K(6209536K), >>> 0.0218000 secs] >>> 2015-11-10T18:41:48.790+0000: 228.702: [GC 2721931K->2066780K(6209536K), >>> 0.0292470 secs] >>> 2015-11-10T18:41:49.290+0000: 229.202: [GC 2722140K->2066843K(6209536K), >>> 0.0288740 secs] >>> 2015-11-10T18:41:49.756+0000: 229.668: [GC 2722203K->2066818K(6209536K), >>> 0.0283380 secs] >>> 2015-11-10T18:41:50.249+0000: 230.161: [GC 2722178K->2067158K(6209536K), >>> 0.0218690 secs] >>> 2015-11-10T18:41:50.713+0000: 230.625: [GC 2722518K->2067236K(6209536K), >>> 0.0278810 secs] >>> >>> This is a VM with 12GB of RAM. Highered the HEAP_SIZE to 6GB and >>> HEAP_NEWSIZE to 800MB. >>> >>> Still the same result. >>> >>> This looks very similar to following issue: >>> >>> http://mail-archives.apache.org/mod_mbox/cassandra-user/201411.mbox/%3CCAJ=3xgRLsvpnZe0uXEYjG94rKhfXeU+jBR=q3a-_c3rsdd5...@mail.gmail.com%3E >>> >>> Is the only possibility to upgrade memory? I mean, I can't believe it's >>> just loading all it's data in memory. That would require to keep scaling up >>> the node to keep it work? >>> >>> >>> 2015-11-10 9:36 GMT+01:00 PenguinWhispererThe . < >>> th3penguinwhispe...@gmail.com>: >>> >>>> Correction... >>>> I was grepping on Segmentation on the strace and it happens a lot. >>>> >>>> Do I need to run a scrub? >>>> >>>> 2015-11-10 9:30 GMT+01:00 PenguinWhispererThe . < >>>> th3penguinwhispe...@gmail.com>: >>>> >>>>> Hi Rob, >>>>> >>>>> Thanks for your reply. >>>>> >>>>> 2015-11-09 23:17 GMT+01:00 Robert Coli <rc...@eventbrite.com>: >>>>> >>>>>> On Mon, Nov 9, 2015 at 1:29 PM, PenguinWhispererThe . < >>>>>> th3penguinwhispe...@gmail.com> wrote: >>>>>>> >>>>>>> In Opscenter I see one of the nodes is orange. It seems like it's >>>>>>> working on compaction. I used nodetool compactionstats and whenever I >>>>>>> did >>>>>>> this the Completed nad percentage stays the same (even with hours in >>>>>>> between). >>>>>>> >>>>>> Are you the same person from IRC, or a second report today of >>>>>> compaction hanging in this way? >>>>>> >>>>> Same person ;) Just didn't had things to work with from the chat >>>>> there. I want to understand the issue more, see what I can tune or fix. I >>>>> want to do nodetool repair before upgrading to 2.1.11 but the compaction >>>>> is >>>>> blocking it. >>>>> >>>>>> >>>>>> >>>>>> >>>>> What version of Cassandra? >>>>>> >>>>> 2.0.9 >>>>> >>>>>> I currently don't see cpu load from cassandra on that node. So it >>>>>>> seems stuck (somewhere mid 60%). Also some other nodes have compaction >>>>>>> on >>>>>>> the same columnfamily. I don't see any progress. >>>>>>> >>>>>>> WARN [RMI TCP Connection(554)-192.168.0.68] 2015-11-09 17:18:13,677 >>>>>>> ColumnFamilyStore.java (line 2101) Unable to cancel in-progress >>>>>>> compactions for usage_record_ptd. Probably there is an unusually large >>>>>>> row in progress somewhere. It is also possible that buggy code left >>>>>>> some sstables compacting after it was done with them >>>>>>> >>>>>>> >>>>>>> - How can I assure that nothing is happening? >>>>>>> >>>>>>> Find the thread that is doing compaction and strace it. Generally it >>>>>> is one of the threads with a lower thread priority. >>>>>> >>>>> >>>>> I have 141 threads. Not sure if that's normal. >>>>> >>>>> This seems to be the one: >>>>> 61404 cassandr 24 4 8948m 4.3g 820m R 90.2 36.8 292:54.47 java >>>>> >>>>> In the strace I see basically this part repeating (with once in a >>>>> while the "resource temporarily unavailable"): >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x7f5c64145e28, FUTEX_WAKE_PRIVATE, 1) = 1 >>>>> getpriority(PRIO_PROCESS, 61404) = 16 >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x7f5c64145e28, FUTEX_WAKE_PRIVATE, 1) = 0 >>>>> futex(0x1233854, FUTEX_WAIT_PRIVATE, 494045, NULL) = -1 EAGAIN >>>>> (Resource temporarily unavailable) >>>>> futex(0x1233828, FUTEX_WAKE_PRIVATE, 1) = 0 >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x7f5c64145e28, FUTEX_WAKE_PRIVATE, 1) = 1 >>>>> futex(0x1233854, FUTEX_WAIT_PRIVATE, 494047, NULL) = 0 >>>>> futex(0x1233828, FUTEX_WAKE_PRIVATE, 1) = 0 >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x7f5c64145e28, FUTEX_WAKE_PRIVATE, 1) = 1 >>>>> getpriority(PRIO_PROCESS, 61404) = 16 >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x7f5c64145e28, FUTEX_WAKE_PRIVATE, 1) = 1 >>>>> futex(0x1233854, FUTEX_WAIT_PRIVATE, 494049, NULL) = 0 >>>>> futex(0x1233828, FUTEX_WAKE_PRIVATE, 1) = 0 >>>>> getpriority(PRIO_PROCESS, 61404) = 16 >>>>> >>>>> But wait! >>>>> I also see this: >>>>> futex(0x7f5c64145e54, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7f5c64145e50, >>>>> {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1 >>>>> futex(0x1233854, FUTEX_WAIT_PRIVATE, 494055, NULL) = 0 >>>>> futex(0x1233828, FUTEX_WAKE_PRIVATE, 1) = 0 >>>>> --- SIGSEGV (Segmentation fault) @ 0 (0) --- >>>>> >>>>> This doesn't seem to happen that often though. >>>>> >>>>>> >>>>>> Compaction often appears hung when decompressing a very large row, >>>>>> but usually not for "hours". >>>>>> >>>>>>> >>>>>>> - Is it recommended to disable compaction from a certain data >>>>>>> size? (I believe 25GB on each node). >>>>>>> >>>>>>> It is almost never recommended to disable compaction. >>>>>> >>>>>>> >>>>>>> - Can I stop this compaction? nodetool stop compaction doesn't >>>>>>> seem to work. >>>>>>> >>>>>>> Killing the JVM ("the dungeon collapses!") would certainly stop it, >>>>>> but it'd likely just start again when you restart the node. >>>>>> >>>>>>> >>>>>>> - Is stopping the compaction dangerous? >>>>>>> >>>>>>> Not if you're in a version that properly cleans up partial >>>>>> compactions, which is most of them. >>>>>> >>>>>>> >>>>>>> - Is killing the cassandra process dangerous while compacting(I >>>>>>> did nodetool drain on one node)? >>>>>>> >>>>>>> No. But probably nodetool drain couldn't actually stop the >>>>>> in-progress compaction either, FWIW. >>>>>> >>>>>>> This is output of nodetool compactionstats grepped for the keyspace >>>>>>> that seems stuck. >>>>>>> >>>>>>> Do you have gigantic rows in that keyspace? What does cfstats say >>>>>> about the largest row compaction has seen/do you have log messages about >>>>>> compacting large rows? >>>>>> >>>>> >>>>> I don't know about the gigantic rows. How can I check? >>>>> >>>>> I've checked the logs and found this: >>>>> INFO [CompactionExecutor:67] 2015-11-10 02:34:19,077 >>>>> CompactionController.java (line 192) Compacting large row >>>>> billing/usage_record_ptd:177727:2015-10-14 00\:00Z (243992466 bytes) >>>>> incrementally >>>>> So this is from 6 hours ago. >>>>> >>>>> I also see a lot of messages like this: >>>>> INFO [OptionalTasks:1] 2015-11-10 06:36:06,395 MeteredFlusher.java >>>>> (line 58) flushing high-traffic column family CFS(Keyspace='mykeyspace', >>>>> ColumnFamily='mycolumnfamily') (estimated 100317609 bytes) >>>>> And (although it's unrelated this might impact compaction >>>>> performance?): >>>>> WARN [Native-Transport-Requests:10514] 2015-11-10 06:33:34,172 >>>>> BatchStatement.java (line 223) Batch of prepared statements for >>>>> [billing.usage_record_ptd] is of size 13834, exceeding specified threshold >>>>> of 5120 by 8714. >>>>> >>>>> It's like the compaction is only doing one sstable at a time and is >>>>> doing nothing a long time in between. >>>>> >>>>> cfstats for this keyspace and columnfamily gives the following: >>>>> Table: mycolumnfamily >>>>> SSTable count: 26 >>>>> Space used (live), bytes: 319858991 >>>>> Space used (total), bytes: 319860267 >>>>> SSTable Compression Ratio: 0.24265700071674673 >>>>> Number of keys (estimate): 6656 >>>>> Memtable cell count: 22710 >>>>> Memtable data size, bytes: 3310654 >>>>> Memtable switch count: 31 >>>>> Local read count: 0 >>>>> Local read latency: 0.000 ms >>>>> Local write count: 997667 >>>>> Local write latency: 0.000 ms >>>>> Pending tasks: 0 >>>>> Bloom filter false positives: 0 >>>>> Bloom filter false ratio: 0.00000 >>>>> Bloom filter space used, bytes: 12760 >>>>> Compacted partition minimum bytes: 1332 >>>>> Compacted partition maximum bytes: 43388628 >>>>> Compacted partition mean bytes: 234682 >>>>> Average live cells per slice (last five minutes): 0.0 >>>>> Average tombstones per slice (last five minutes): 0.0 >>>>> >>>>> >>>>>> I also see frequently lines like this in system.log: >>>>>>> >>>>>>> WARN [Native-Transport-Requests:11935] 2015-11-09 20:10:41,886 >>>>>>> BatchStatement.java (line 223) Batch of prepared statements for >>>>>>> [billing.usage_record_by_billing_period, billing.metric] is of size >>>>>>> 53086, exceeding specified threshold of 5120 by 47966. >>>>>>> >>>>>>> >>>>>> Unrelated. >>>>>> >>>>>> =Rob >>>>>> >>>>>> >>>>> >>>>> Can I upgrade to 2.1.11 without doing a nodetool repair/compaction >>>>> being stuck? >>>>> Another thing to mention is that nodetool repair didn't run yet. It >>>>> got installed but nobody bothered to schedule the repair. >>>>> >>>>> Thanks for looking into this! >>>>> >>>> >>>> >>> >> >
