flink-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Tzu-Li (Gordon) Tai" <tzuli...@apache.org>
Subject Re: Fault tolerance guarantees of Elasticsearch sink in flink-elasticsearch2?
Date Wed, 18 Jan 2017 09:21:45 GMT
Hi Andrew!

There’s nothing special about extending the checkpointing interfaces for the SinkFunction;
for Flink they’re essentially user functions that have user state to be checkpointed.
So yes, you’ll just implement is as you would for a flatMap / map / etc. function.

Fell free to let me know if you bump into any questions.


On January 16, 2017 at 11:37:30 PM, Andrew Roberts (aroberts@fuze.com) wrote:

Hi Gordon,

Thanks for getting back to me. The ticket looks good, but I’m going to need to do something
similar for our homegrown sinks. It sounds like just having the affected sinks participate
in checkpointing is enough of a solution - is there anything special about `SinkFunction[T]`
extending `Checkpointed[S]`, or can I just implement it as I would for e.g. a mapping function?



On Jan 13, 2017, at 4:34 PM, Tzu-Li (Gordon) Tai <tzulitai@apache.org> wrote:

Hi Andrew,

Your observations are correct. Like you mentioned, the current problem circles around how
we deal with the pending buffered requests with accordance to Flink’s checkpointing.
I’ve filed a JIRA for this, as well as some thoughts for the solution in the description: https://issues.apache.org/jira/browse/FLINK-5487.
What do you think?

Thank you for bringing this up! We should probably fix this soon.
There’s already some on-going effort in fixing some other aspects of proper at-least-once
support in the Elasticsearch sinks, so I believe this will be brought to attention very soon


On January 11, 2017 at 3:49:06 PM, Andrew Roberts (aroberts@fuze.com) wrote:

I’m trying to understand the guarantees made by Flink’s Elasticsearch sink in terms of
message delivery. according to (1), the ES sink offers at-least-once guarantees. This page
doesn’t differentiate between flink-elasticsearch and flink-elasticsearch2, so I have to
assume for the moment that they both offer that guarantee. However, a look at the code (2)
shows that the invoke() method puts the record into a buffer, and then that buffer is flushed
to elasticsearch some time later.

View raw message