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From Patrik Kleindl <pklei...@gmail.com>
Subject Re: Kafka streams (2.1.1) - org.rocksdb.RocksDBException:Too many open files
Date Thu, 27 Jun 2019 09:02:39 GMT
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, emailtokirank@gmail.com <
emailtokirank@gmail.com> wrote:

>
>
> On 2019/06/26 21:58:02, Patrik Kleindl <pkleindl@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, emailtokirank@gmail.com <
> > emailtokirank@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
>
>

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