Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-14 Thread Theodore Vasiloudis
Hello all, I would also be really interested in how a PS-like architecture would work in Flink. Note that we not necessarily talking about PS, but generally how QueryableState can be used for ML tasks with I guess a focus on model-parallel training. One suggestion I would make is to take a look

Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-14 Thread Gábor Hermann
Hey Ufuk, I'm happy to contribute. At least I'll get a bit more understanding of the details. Breaking the assumption that only a single thread updates state would brings us from strong isolation guarantees (i.e. serializability at the updates and read committed at the external queries) to

Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-14 Thread Ufuk Celebi
Hey Gabor, great ideas here. It's only slightly related, but I'm currently working on a proposal to improve the queryable state APIs for lookups (partly along the lines of what you suggested with higher level accessors). Maybe you are interested in contributing there? I really like your ideas

Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-14 Thread Gábor Hermann
Hi Gyula, Jinkui Shi, Thanks for your thoughts! @Gyula: I'll try and explain a bit more detail. The API could be almost like the QueryableState's. It could be higher-level though: returning Java objects instead of serialized data (because there would not be issues with class loading). Also,

Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-12 Thread Jinkui Shi
hi,Gábor Hermann The online parameter server is a good proposal. PS’ paper [1] have a early implement [2], and now it’s mxnet [3]. I have some thought about online PS in Flink: 1. Whether support flexible and configurable update strategy? For example, in one iteration, computing

Re: Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-11 Thread Gyula Fóra
Hi Gábor, I think the general idea is very nice, but it would nice to see clearer what benefit does this bring from the developers perspective. Maybe rough API sketch and 1-2 examples. I am wondering what sort of consistency guarantees do you imagine for such operations, or why the fault

Using QueryableState inside Flink jobs (and Parameter Server implementation)

2017-02-10 Thread Gábor Hermann
Hi all, TL;DR: Is it worth to implement a special QueryableState for querying state from another part of a Flink streaming job and aligning it with fault tolerance? I've been thinking about implementing a Parameter Server with/within Flink. A Parameter Server is basically a specialized