Re: Message guarantees with S3 Sink

2018-05-21 Thread Amit Jain
Thanks Gary! Sure, there are issues with updates in S3. You may want to look over EMRFS guarantees of the consistent view [1]. I'm not sure, is it possible in non-EMR AWS system or not. I'm creating a JIRA issue regarding data loss possibility in S3. IMHO, Flink docs should mention about possible

Re: Message guarantees with S3 Sink

2018-05-17 Thread Gary Yao
Hi Amit, The BucketingSink doesn't have well defined semantics when used with S3. Data loss is possible but I am not sure whether it is the only problem. There are plans to rewrite the BucketingSink in Flink 1.6 to enable eventually consistent file systems [1][2]. Best, Gary [1] http://apache-f

Re: Message guarantees with S3 Sink

2018-05-17 Thread Amit Jain
Hi Rong, We are using BucketingSink only. I'm looking for the case where TM does not get the chance to call Writer#flush like YARN killed the TM because of OOM. We have configured fs.s3.impl to com.amazon.ws.emr.hadoop.fs.EmrFileSystem in core-site.xml, so BucketingSink is using S3 client internal

Re: Message guarantees with S3 Sink

2018-05-17 Thread Rong Rong
Hi Amit, Can you elaborate how you write using "S3 sink" and which version of Flink you are using? If you are using BucketingSink[1], you can checkout the API doc and configure to flush before closing your sink. This way your sink is "integrated with the checkpointing mechanism to provide exactly

Message guarantees with S3 Sink

2018-05-17 Thread Amit Jain
Hi, We are using Flink to process click stream data from Kafka and pushing the same in 128MB file in S3. What is the message processing guarantees with S3 sink? In my understanding, S3A client buffers the data on memory/disk. In failure scenario on particular node, TM would not trigger Writer#clo