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From Elias Levy <fearsome.lucid...@gmail.com>
Subject Re: metrics for Flink sinks
Date Thu, 31 Aug 2017 00:22:15 GMT
Not an exact match, but I am guessing it is related to FLINK-7286
<https://issues.apache.org/jira/projects/FLINK/issues/FLINK-7286>, which I
reported.  Feel free to modify that issue to cover the root cause.

On Wed, Aug 30, 2017 at 8:32 AM, Martin Eden <martineden131@gmail.com>

> Thanks Chesnay,
> Just for completeness, are there any relevant tickets for the discussion
> that one can follow, upvote, contribute to?
> M
> On Tue, Aug 29, 2017 at 8:57 PM, Chesnay Schepler <chesnay@apache.org>
> wrote:
>> Hello,
>> 1. Because no one found time to fix it. In contrast to the remaining
>> byte/record metrics, input metrics for sources / output metrics for sinks
>> have to be implemented for every single implementation with their
>> respective semantics. In contrast, the output metrics are gathered in the
>> intersection between operators, independent of the actual operator
>> implementation. Furthermore, this requires system metrics (i.e. metrics
>> that Flink itself creates) to be exposed (and be mutable!) to user-defined
>> functions, which is something i *generally *wanted to avoid, but it
>> appears to be a big enough pain point to make an exception here.
>> 2. Due to the above it is currently not possible without modifications of
>> the code to know how many reads/writes were made.
>> 3. Do you mean aggregated metrics? The web UI allows the aggregation of
>> record/byte metrics on the task level. Beyond that we defer aggregation to
>> actual time-series databases that specialize in these things.
>> On 28.08.2017 19:08, Martin Eden wrote:
>> Hi all,
>> Just 3 quick questions both related to Flink metrics, especially around
>> sinks:
>> 1. In the Flink UI Sources always have 0 input records / bytes and Sinks
>> always have 0 output records / bytes? Why is it like that?
>> 2. What is the best practice for instrumenting off the shelf Flink sinks?
>> Currently the only metrics available are num records/bytes in and out at
>> the operator and task scope. For the task scope there are extra buffer
>> metrics. However the output metrics are always zero (see question 1). How
>> can one know the actual number of successful writes done by an off the
>> shelf Flink sink? Or the latency of the write operation?
>> 3. Is it possible to configure Flink to get global job metrics for all
>> subtasks of an operator? Or are there any best practices around that?
>> Thanks,
>> M

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