[ https://issues.apache.org/jira/browse/FLINK-6761?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16028363#comment-16028363 ]
Stefan Richter commented on FLINK-6761: --------------------------------------- Opened a corresponding issue in the RocksDB tracker: https://github.com/facebook/rocksdb/issues/2383 > Limitation for maximum state size per key in RocksDB backend > ------------------------------------------------------------ > > Key: FLINK-6761 > URL: https://issues.apache.org/jira/browse/FLINK-6761 > Project: Flink > Issue Type: Bug > Components: State Backends, Checkpointing > Affects Versions: 1.3.0, 1.2.1 > Reporter: Stefan Richter > Priority: Critical > > RocksDB`s JNI bridge allows for putting and getting {{byte[]}} as keys and > values. > States that internally use RocksDB's merge operator, e.g. {{ListState}}, can > currently merge multiple {{byte[]}} under one key, which will be internally > concatenated to one value in RocksDB. > This becomes problematic, as soon as the accumulated state size under one key > grows larger than {{Integer.MAX_VALUE}} bytes. Whenever Java code tries to > access a state that grew beyond this limit through merging, we will encounter > an {{ArrayIndexOutOfBoundsException}} at best and a segfault at worst. > This behaviour is problematic, because RocksDB silently stores states that > exceed this limitation, but on access (e.g. in checkpointing), the code fails > unexpectedly. > I think the only proper solution to this is for RocksDB's JNI bridge to build > on {{(Direct)ByteBuffer}} - which can go around the size limitation - as > input and output types, instead of simple {{byte[]}}. -- This message was sent by Atlassian JIRA (v6.3.15#6346)