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 >
