[
https://issues.apache.org/jira/browse/KAFKA-9603?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17105703#comment-17105703
]
Bruno Cadonna commented on KAFKA-9603:
--------------------------------------
I think I found the cause of this issue. With segmented state stores (i.e.,
state stores used to store windowed data), bulk loading mode of RocksDB might
be turned on but never off on stand-by tasks. I opened the following PR with a
fix:
https://github.com/apache/kafka/pull/8661
> Number of open files keeps increasing in Streams application
> ------------------------------------------------------------
>
> Key: KAFKA-9603
> URL: https://issues.apache.org/jira/browse/KAFKA-9603
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.1.0, 2.2.0, 2.4.0, 2.3.1
> Environment: Spring Boot 2.2.4, OpenJDK 13, Centos image
> Reporter: Bruno Iljazovic
> Assignee: Bruno Cadonna
> Priority: Major
>
> Problem appeared when upgrading from *2.0.1* to *2.3.1*.
> Relevant Kafka Streams code:
> {code:java}
> KStream<String, Event1> events1 =
> builder.stream(FIRST_TOPIC_NAME, Consumed.with(stringSerde, event1Serde,
> event1TimestampExtractor(), null))
> .mapValues(...);
> KStream<String, Event2> events2 =
> builder.stream(SECOND_TOPIC_NAME, Consumed.with(stringSerde, event2Serde,
> event2TimestampExtractor(), null))
> .mapValues(...);
> var joinWindows = JoinWindows.of(Duration.of(1, MINUTES).toMillis())
> .until(Duration.of(1, HOURS).toMillis());
> events2.join(events1, this::join, joinWindows, Joined.with(stringSerde,
> event2Serde, event1Serde))
> .foreach(...);
> {code}
> Number of open *.sst files keeps increasing until eventually it hits the os
> limit (65536) and causes this exception:
> {code:java}
> Caused by: org.rocksdb.RocksDBException: While open a file for appending:
> /.../0_8/KSTREAM-JOINOTHER-0000000010-store/KSTREAM-JOINOTHER-0000000010-store.1579435200000/001354.sst:
> Too many open files
> at org.rocksdb.RocksDB.flush(Native Method)
> at org.rocksdb.RocksDB.flush(RocksDB.java:2394)
> {code}
> Here are example files that are opened and never closed:
> {code:java}
> /.../0_27/KSTREAM-JOINTHIS-0000000009-store/KSTREAM-JOINTHIS-0000000009-store.1582459200000/000114.sst
> /.../0_27/KSTREAM-JOINOTHER-0000000010-store/KSTREAM-JOINOTHER-0000000010-store.1582459200000/000065.sst
> /.../0_29/KSTREAM-JOINTHIS-0000000009-store/KSTREAM-JOINTHIS-0000000009-store.1582156800000/000115.sst
> /.../0_29/KSTREAM-JOINTHIS-0000000009-store/KSTREAM-JOINTHIS-0000000009-store.1582459200000/000112.sst
> /.../0_31/KSTREAM-JOINTHIS-0000000009-store/KSTREAM-JOINTHIS-0000000009-store.1581854400000/000051.sst
> {code}
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
