That would be great, thank you. On Fri, Jul 5, 2019 at 5:40 PM Gidon Gershinsky <[email protected]> wrote:
> Hi Junjie, > > I'd be glad to have a look at the encryption part. Will add my comments > early next week. > > Cheers, Gidon. > > On Fri, Jul 5, 2019 at 12:16 PM 俊杰陈 <[email protected]> wrote: > > > Sorry, the latest file is > > > > > https://github.com/chenjunjiedada/parquet-format/blob/PARQUET-1617/BloomFilter.md > > . > > > > On Fri, Jul 5, 2019 at 5:14 PM 俊杰陈 <[email protected]> wrote: > > > > > Sure, please see this PR > > > <https://github.com/apache/parquet-format/pull/140> or update file > here > > > < > > > https://github.com/chenjunjiedada/parquet-format/blob/master/BloomFilter.md > > > > > > . > > > > > > Thanks for reviewing spec. > > > > > > On Thu, Jul 4, 2019 at 11:57 PM Zoltan Ivanfi <[email protected] > > > > > wrote: > > > > > >> Hi Junjie, > > >> > > >> I read through the specification and while I support the feature in > > >> general, I find that the documentation may not be detailed enough to > > allow > > >> developers of different language bindings to implement it. > > Specifically, > > >> the Technical Approach section of the docs is very short and refers > the > > >> reader to two publications for details. I think the specification > would > > >> greatly benefit from including an explanation or a summary of the > > approach > > >> in this section. > > >> > > >> The "Build a Bloom filter" section contains a formula for calculating > > the > > >> optimal filter size for a desired false positive rate, but does not > > >> specify > > >> what false positive rates implementations should target by default and > > >> through what ways should they make it configurable by users. I > > understand > > >> that this may be an intentional omission, since targeting any false > > >> positive rate will result in a specification-compliant result, still I > > >> think it would be best to provide some recommendation for the > different > > >> language bindings. > > >> > > >> Since this feature is getting added after encryption, it should be > > briefly > > >> but explicitly mentioned how it interacts with that (basically that it > > has > > >> to be encrypted, otherwise it would leak sensitive information, but by > > >> placing it inside the column chunk metadata, this is automatically > taken > > >> care of). > > >> > > >> Finally, as a nitpick, I would prefer in-line links to related > materials > > >> instead of numeric references that one must manually look up at the > > bottom > > >> of the page. > > >> > > >> Could you please add these improvements to the specification? > > >> > > >> Thanks, > > >> > > >> Zoltan > > >> > > >> On Wed, Jul 3, 2019 at 4:03 PM 俊杰陈 <[email protected]> wrote: > > >> > > >> > You are welcome, it 's my honor. > > >> > > > >> > I think the PR <https://github.com/apache/parquet-format/pull/139> > > just > > >> > remove murmur3, that should express what I want. > > >> > > > >> > > > >> > > > >> > > > >> > On Wed, Jul 3, 2019 at 9:53 PM Zoltan Ivanfi > <[email protected] > > > > > >> > wrote: > > >> > > > >> > > Hi Junjie, > > >> > > > > >> > > Thanks for the update and also for your endruance in going through > > >> this > > >> > > tedious process in order to add bloom filtering to Parquet. > > >> > > > > >> > > I understand that your proposal is to go forward with xxHash > instead > > >> of > > >> > the > > >> > > eralier murmur3, which you suggest to deprecate. Since the murmur3 > > >> hash > > >> > was > > >> > > never released, I think it could be completely removed from the > spec > > >> > > instead of just getting deprecated. What is your opinion on this? > > >> > > > > >> > > Thanks, > > >> > > > > >> > > Zoltan > > >> > > > > >> > > On Wed, Jul 3, 2019 at 3:31 PM 俊杰陈 <[email protected]> wrote: > > >> > > > > >> > > > I see, thanks for guiding on this. > > >> > > > > > >> > > > Per discussion in this thread and some investigation about > changes > > >> on > > >> > > > current java and c++ implementation, and I think that is not > hard > > to > > >> > > > handle. So I propose to use xxHash (the XXH64 version) as the > > >> default > > >> > > > hash strategy and deprecate previous murmur3 hash. > > >> > > > > > >> > > > I will update vote thread as well to make it clearer to all. > > >> > > > > > >> > > > > > >> > > > On Wed, Jul 3, 2019 at 6:08 PM Zoltan Ivanfi > > >> <[email protected]> > > >> > > > wrote: > > >> > > > > > > >> > > > > Hi Junjie, > > >> > > > > > > >> > > > > I think the vote is ambigous in its current form (can people > > vote > > >> on > > >> > > one > > >> > > > > option only or can they vote on both?) and has a low chance of > > >> > getting > > >> > > > > votes in general because it's not a yes/no question but a > > >> > > > > choose-an-approach question instead. I think most contributors > > >> would > > >> > > > accept > > >> > > > > the hash chosen based on a community discussion but would be > > >> > reluctant > > >> > > to > > >> > > > > make that choice themselves in the form a vote because it > > >> requires a > > >> > > much > > >> > > > > deeper dive into the technical intricacies involved. The > > >> committers > > >> > are > > >> > > > > experienced in the parquet code base but may not be as > > >> experienced in > > >> > > > bloom > > >> > > > > filters as you are. > > >> > > > > > > >> > > > > In my opinion, to get bloom filtering into parquet-mr, you > > should > > >> > > > convince > > >> > > > > the committers that the proposal is viable by addressing their > > >> > concerns > > >> > > > > (which I believe you have done), and not by delegating the > task > > of > > >> > > making > > >> > > > > choices to them. I would suggest that you propose which one > (or > > >> both) > > >> > > of > > >> > > > > the hashes should be included, summarize your motivations in > > this > > >> > > thread > > >> > > > > and if you don't get any objections for a day or two, call a > > >> YES/NO > > >> > > vote > > >> > > > > for that specific proposal in a separate thread. > > >> > > > > > > >> > > > > Thanks, > > >> > > > > > > >> > > > > Zoltan > > >> > > > > > > >> > > > > On Tue, Jul 2, 2019 at 3:52 AM 俊杰陈 <[email protected]> > wrote: > > >> > > > > > > >> > > > > > Any thoughts from other committers and developers? > > >> > > > > > > > >> > > > > > I 'd like to start a vote firstly, you could either provide > > your > > >> > > input > > >> > > > here > > >> > > > > > or on vote thread. > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > On Mon, Jul 1, 2019 at 8:20 PM Zoltan Ivanfi > > >> > <[email protected] > > >> > > > > > >> > > > > > wrote: > > >> > > > > > > > >> > > > > > > Hi, > > >> > > > > > > > > >> > > > > > > I would like to clarify one point of my previous e-mail: > > >> While I > > >> > > > reasoned > > >> > > > > > > that for compressions and encodings we should avoid > picking > > >> > > > algorithms > > >> > > > > > > superseded by better ones, I also reasoned that for bloom > > >> filters > > >> > > we > > >> > > > do > > >> > > > > > not > > >> > > > > > > necessarily have to be as strict, because a reader with > > >> missing > > >> > > > > > > implementation will still be able to read data from files > > that > > >> > > > contain > > >> > > > > > > unsupported bloom filter data structures. > > >> > > > > > > > > >> > > > > > > Personally I'm fine with moving forward with the current > > hash > > >> > > > proposal, > > >> > > > > > > even if the chosen algorithm is not considered to be the > > best > > >> of > > >> > > its > > >> > > > > > class. > > >> > > > > > > > > >> > > > > > > Br, > > >> > > > > > > > > >> > > > > > > Zoltan > > >> > > > > > > > > >> > > > > > > On Sun, Jun 30, 2019 at 11:02 PM Jim Apple < > > >> [email protected]> > > >> > > > wrote: > > >> > > > > > > > > >> > > > > > > > On 2019/06/28 16:43:23, Ryan Blue > > <[email protected] > > >> > > > >> > > > wrote: > > >> > > > > > > > > I agree with Zoltan. Since we want to ensure > > >> compatibility, > > >> > it > > >> > > > would > > >> > > > > > be > > >> > > > > > > > > better to choose the best option now instead of making > > >> > everyone > > >> > > > > > support > > >> > > > > > > > two > > >> > > > > > > > > options forever. > > >> > > > > > > > > > >> > > > > > > > I'd guess there probably isn't a single best option. I > > >> suspect > > >> > > > there's > > >> > > > > > a > > >> > > > > > > > tradeoff between ease of implementation and speed, for > > >> > instance, > > >> > > > since > > >> > > > > > I > > >> > > > > > > > expect it's easy to find an MD5 library in most > > programming > > >> > > > languages > > >> > > > > > and > > >> > > > > > > > operating systems, yet MD5 is very slow compared to > > >> > > > non-cryptographic > > >> > > > > > > hash > > >> > > > > > > > functions designed for speed like xxhash. > > >> > > > > > > > > > >> > > > > > > > There's also a significant amount of variability across > > >> > processor > > >> > > > > > > families > > >> > > > > > > > (64-bit multiply-shift in ARM vs x86-64) or even > different > > >> > > > versions of > > >> > > > > > > the > > >> > > > > > > > same processor family (CLHash in Haswell vs. Sandy > Lake). > > >> There > > >> > > are > > >> > > > > > also > > >> > > > > > > > quality tradeoffs that depend on the average bye length > of > > >> the > > >> > > > input > > >> > > > > > (FNV > > >> > > > > > > > vs vhash) or how much L1 cache the user wants to use for > > the > > >> > hash > > >> > > > > > > function > > >> > > > > > > > (tabulation hashing vs. multiply-shift). > > >> > > > > > > > > > >> > > > > > > > To deal with this level of ambiguity, I'd suggest that > v1 > > >> > should > > >> > > > > > include > > >> > > > > > > a > > >> > > > > > > > hash function that works well for certain common > > >> environments. > > >> > As > > >> > > > far > > >> > > > > > as > > >> > > > > > > I > > >> > > > > > > > know, murmur and xxhash would both fit that bill. > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > -- > > >> > > > > > Thanks & Best Regards > > >> > > > > > > > >> > > > > > >> > > > > > >> > > > > > >> > > > -- > > >> > > > Thanks & Best Regards > > >> > > > > > >> > > > > >> > > > >> > > > >> > -- > > >> > Thanks & Best Regards > > >> > > > >> > > > > > > > > > -- > > > Thanks & Best Regards > > > > > > > > > -- > > Thanks & Best Regards > > > -- Thanks & Best Regards
