This can also happen if you have any open iterators that you forget to close (for example using IQ), although that's probably not what's going on here since 3152 is certainly a lot of rocks instances for a single fs.
There's no default number of open files per instance, since rocks creates new files on new levels as you add more data. To understand the impact you should check out the description of *max_open_files* here <https://github.com/facebook/rocksdb/wiki/RocksDB-Tuning-Guide#general-options> -- but you will probably want to increase your system limit in addition to constraining the number of open files per instance On Mon, Jul 1, 2019 at 9:58 AM emailtokir...@gmail.com < emailtokir...@gmail.com> wrote: > > > On 2019/06/28 23:29:16, John Roesler <j...@confluent.io> wrote: > > Hey all, > > > > If you want to figure it out theoretically, if you print out the > > topology description, you'll have some number of state stores listed > > in there. The number of Rocks instances should just be > > (#global_state_stores + > > sum(#partitions_of_topic_per_local_state_store)) . The number of > > stream threads isn't relevant here. > > > > You can also figure it out empirically: the first level of > > subdirectories in the state dir are Tasks, and then within that, the > > next level is Stores. You should see the store directory names match > > up with the stores listed in the topology description. The number of > > Store directories is exactly the number of RocksDB instances you have. > > > > There are also metrics corresponding to each of the state stores, so > > you can compute it from what you find in the metrics. > > > > Hope that helps, > > -john > > > > On Thu, Jun 27, 2019 at 6:46 AM Patrik Kleindl <pklei...@gmail.com> > wrote: > > > > > > Hi Kiran > > > Without much research my guess would be "num_stream_threads * > > > (#global_state_stores + > sum(#partitions_of_topic_per_local_state_store))" > > > So 10 stores (regardless if explicitly defined or implicitely because > of > > > some stateful operation) with 10 partitions each should result in 100 > > > Rocksdb instances if you are running at the default of > num_stream_threads=1. > > > > > > As I wrote before, start with 100. > > > If the error persists, half the number, if not, double it ;-) Repeat as > > > needed. > > > > > > If you reach the single-digit-range and the error still shows up, start > > > searching for any iterators over a store you might not have closed. > > > > > > br, Patrik > > > > > > On Thu, 27 Jun 2019 at 13:11, emailtokir...@gmail.com < > > > emailtokir...@gmail.com> wrote: > > > > > > > > > > > > > > > On 2019/06/27 09:02:39, Patrik Kleindl <pklei...@gmail.com> wrote: > > > > > Hello Kiran > > > > > > > > > > First, the value for maxOpenFiles is per RocksDB instance, and the > number > > > > > of those can get high if you have a lot of topic partitions etc. > > > > > Check the directory (state dir) to see how many there are. > > > > > Start with a low value (100) and see if that has some effect. > > > > > > > > > > Second, because I just found out, you should use > > > > > BlockBasedTableConfig tableConfig = (BlockBasedTableConfig) > > > > > options.tableFormatConfig(); > > > > > tableConfig.setBlockCacheSize(100*1024*1024L); > > > > > tableConfig.setBlockSize(8*1024L); > > > > > instead of creating a new object to prevent accidently messing up > > > > > references. > > > > > > > > > > Hope that helps > > > > > best regards > > > > > Patrik > > > > > > > > > > On Thu, 27 Jun 2019 at 10:46, emailtokir...@gmail.com < > > > > > emailtokir...@gmail.com> wrote: > > > > > > > > > > > > > > > > > > > > > > > On 2019/06/26 21:58:02, Patrik Kleindl <pklei...@gmail.com> > wrote: > > > > > > > Hi Kiran > > > > > > > You can use the RocksDBConfigSetter and pass > > > > > > > > > > > > > > options.setMaxOpenFiles(100); > > > > > > > > > > > > > > to all RocksDBs for the Streams application which limits how > many are > > > > > > > kept open at the same time. > > > > > > > > > > > > > > best regards > > > > > > > > > > > > > > Patrik > > > > > > > > > > > > > > > > > > > > > On Wed, 26 Jun 2019 at 16:14, emailtokir...@gmail.com < > > > > > > > emailtokir...@gmail.com> wrote: > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > We are using Kafka streams DSL APIs for doing some counter > > > > aggregations > > > > > > > > (running on OpenJDK 11.0.2). Our topology has some 400 sub > > > > topologies > > > > > > & we > > > > > > > > are using 8 partitions in source topic. When we start > pumping more > > > > > > load, we > > > > > > > > start getting RockDBException stating "too many open files". > > > > > > > > > > > > > > > > Here are the stack trace samples: > > > > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------------------ > > > > > > > > Caused by: org.rocksdb.RocksDBException: while open a file > for > > > > lock: > > > > > > > > PPPPPPPPPPP.1512000000/LOCK: Too many open files > > > > > > > > at org.rocksdb.RocksDB.open(Native Method) > > > > > > > > at org.rocksdb.RocksDB.open(RocksDB.java:235) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.RocksDBStore.openDB(RocksDBStore.java:156) > > > > > > > > ... 24 common frames omitted > > > > > > > > > > > > > > > > > > > > > > > > Caused by: > org.apache.kafka.streams.errors.ProcessorStateException: > > > > > > Error > > > > > > > > while executing flush from store XXXXXXXXXXX.1512000000 > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.RocksDBStore.flushInternal(RocksDBStore.java:397) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.RocksDBStore.flush(RocksDBStore.java:388) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.Segments.flush(Segments.java:163) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.RocksDBSegmentedBytesStore.flush(RocksDBSegmentedBytesStore.java:178) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.WrappedStateStore$AbstractStateStore.flush(WrappedStateStore.java:85) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.WrappedStateStore$AbstractStateStore.flush(WrappedStateStore.java:85) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.CachingWindowStore.flush(CachingWindowStore.java:130) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.MeteredWindowStore.flush(MeteredWindowStore.java:177) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.processor.internals.ProcessorStateManager.flush(ProcessorStateManager.java:217) > > > > > > > > ... 10 more > > > > > > > > Caused by: org.rocksdb.RocksDBException: While open a file > for > > > > > > appending: > > > > > > > > YYYYYYYYYYYYY.1512000000/000007.dbtmp: Too many open files > > > > > > > > at org.rocksdb.RocksDB.flush(Native Method) > > > > > > > > at org.rocksdb.RocksDB.flush(RocksDB.java:3401) > > > > > > > > at org.rocksdb.RocksDB.flush(RocksDB.java:3361) > > > > > > > > at > > > > > > > > > > > > > > > > > > > org.apache.kafka.streams.state.internals.RocksDBStore.flushInternal(RocksDBStore.java:395) > > > > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------------------ > > > > > > > > > > > > > > > > We tried increasing the open files limit at OS level to some > decent > > > > > > > > number.. but still no luck. Obviously we don't want to have > > > > boundless > > > > > > open > > > > > > > > files.. > > > > > > > > > > > > > > > > We also tried to play with commit interval( > > > > kafka.commit.interval.ms) > > > > > > and > > > > > > > > cache size (kafka.cache.max.bytes.buffering) .. but no luck > there > > > > > > either. > > > > > > > > > > > > > > > > KAFKA-3904 talks about it.. but it was resolved long back.. > > > > > > > > > > > > > > > > Any other config tuning we have to do? > > > > > > > > > > > > > > > > Appreciate any help in this regard! > > > > > > > > > > > > > > > > Thanks, > > > > > > > > Kiran > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Patrik/All, > > > > > > > > > > > > Thanks for providing some valuable pointer! > > > > > > > > > > > > I did that & it doesn't seems to work. > > > > > > > > > > > > Here is how my custom config setter looks like: > > > > > > > > > > > > > > > > > > > > > > > ---------------------------------------------------------------------------------------------------- > > > > > > > > > > > > > > > > > > @Override > > > > > > public void setConfig(final String storeName, final > Options > > > > > > options, final Map<String, Object> configs) { > > > > > > // See #1 below. > > > > > > BlockBasedTableConfig tableConfig = new > > > > > > org.rocksdb.BlockBasedTableConfig(); > > > > > > > > > > > > tableConfig.setBlockCacheSize(16 * 1024 * 1024L); > > > > > > // See #2 below. > > > > > > tableConfig.setBlockSize(16 * 1024L); > > > > > > // See #3 below. > > > > > > tableConfig.setCacheIndexAndFilterBlocks(false); > > > > > > // > tableConfig.setPinL0FilterAndIndexBlocksInCache(true); > > > > > > options.setMaxOpenFiles(-1); > > > > > > options.setTableFormatConfig(tableConfig); > > > > > > // See #4 below. > > > > > > options.setMaxWriteBufferNumber(2); > > > > > > } > > > > > > > > > > > > > > > > > ---------------------------------------------------------------------------------------------------- > > > > > > I tried many options with this: > > > > > > 1. tableConfig.setCacheIndexAndFilterBlocks(true); ----> as per > docs ( > > > > > > > > > > > https://github.com/facebook/rocksdb/wiki/Memory-usage-in-RocksDB#indexes-and-filter-blocks > > > > ) > > > > > > if we set to true, the max_open_files shouldn't play a role. But > I was > > > > > > still getting too many open files exception from Rocksdb > > > > > > > > > > > > 2. tableConfig.setCacheIndexAndFilterBlocks(true); > > > > > > tableConfig.setPinL0FilterAndIndexBlocksInCache(true); ----> no > luck; > > > > same > > > > > > exception > > > > > > > > > > > > 3. tableConfig.setCacheIndexAndFilterBlocks(false); and > > > > > > options.setMaxOpenFiles(50000); -----> This also resulted > with > > > > same > > > > > > exception.. with java process having ~24K open files > > > > > > > > > > > > 4. tableConfig.setCacheIndexAndFilterBlocks(false); and > > > > > > options.setMaxOpenFiles(-1); -----> This also resulted with > same > > > > > > exception.. with java process having ~24K ope files. As per the > doc, > > > > if we > > > > > > set to -1, it means infinite and controlled by underlying OS > limit. > > > > > > > > > > > > I am using MacOS Mojave (10.14.4) and OpenJDK 11.0.2. At OS > level, I > > > > have > > > > > > bumped the open files limit to 1 million. > > > > > > > > > > > > $ ulimit -a > > > > > > core file size (blocks, -c) 0 > > > > > > data seg size (kbytes, -d) unlimited > > > > > > file size (blocks, -f) unlimited > > > > > > max locked memory (kbytes, -l) unlimited > > > > > > max memory size (kbytes, -m) unlimited > > > > > > open files (-n) 1000000 > > > > > > pipe size (512 bytes, -p) 1 > > > > > > stack size (kbytes, -s) 8192 > > > > > > cpu time (seconds, -t) unlimited > > > > > > max user processes (-u) 1418 > > > > > > virtual memory (kbytes, -v) unlimited > > > > > > > > > > > > > > > > > > Am I missing some other config here? > > > > > > > > > > > > Thanks, > > > > > > Kiran > > > > > > > > > > > > > > > > > > > > > > > > > Hi Patrik, > > > > > > > > Thanks for quick response! > > > > > > > > I just checked the state dir. It has total of 3152 sub folders and > total > > > > of 15451 files (within sub folders..). > > > > > > > > With this what should be the number that I should use? > > > > > > > > How many instances of rocksdb will be used? Any formula to determine > that? > > > > > > > > Thanks again, > > > > Kiran > > > > > > > > Thanks Patrik & John for sharing some more insights! > > So as per your explanation, we have 3152 instances of rocksdb. By default > how many open files does rocksdb create per instance? Say by default it > needs some 20 files & if I set it as 10, what will be the impact? > > I was going through this: > https://github.com/facebook/rocksdb/wiki/Memory-usage-in-RocksDB#indexes-and-filter-blocks > > But couldn't get conclusive answer.. may be I might have missed to read > some sections? > > Thanks, > Kiran >
