On Wed, Oct 9, 2019 at 10:16 PM Renjie Liu <liurenjie2...@gmail.com> wrote: > > 1. There already exists a low level parquet writer which can produce > parquet file, so unit test should be fine. But writer from arrow to parquet > doesn't exist yet, and it may take some period of time to finish it. > 2. In fact my data are randomly generated and it's definitely reproducible. > However, I don't think it would be good idea to randomly generate data > everytime we run ci because it would be difficult to debug. For example PR > a introduced a bug, which is triggerred in other PR's build it would be > confusing for contributors.
Presumably any random data generation would use a fixed seed precisely to be reproducible. > 3. I think it would be good idea to spend effort on integration test with > parquet because it's an important use case of arrow. Also similar approach > could be extended to other language and other file format(avro, orc). > > > On Wed, Oct 9, 2019 at 11:08 PM Wes McKinney <wesmck...@gmail.com> wrote: > > > There are a number of issues worth discussion. > > > > 1. What is the timeline/plan for Rust implementing a Parquet _writer_? > > It's OK to be reliant on other libraries in the short term to produce > > files to test against, but does not strike me as a sustainable > > long-term plan. Fixing bugs can be a lot more difficult than it needs > > to be if you can't write targeted "endogenous" unit tests > > > > 2. Reproducible data generation > > > > I think if you're going to test against a pre-generated corpus, you > > should make sure that generating the corpus is reproducible for other > > developers (i.e. with a Dockerfile), and can be extended by adding new > > files or random data generation. > > > > I additionally would prefer generating the test corpus at test time > > rather than checking in binary files. If this isn't viable right now > > we can create an "arrow-rust-crutch" git repository for you to stash > > binary files until some of these testing scalability issues are > > addressed. > > > > If we're going to spend energy on Parquet integration testing with > > Java, this would be a good opportunity to do the work in a way where > > the C++ Parquet library can also participate (since we ought to be > > doing integration tests with Java, and we can also read JSON files to > > Arrow). > > > > On Tue, Oct 8, 2019 at 11:54 PM Renjie Liu <liurenjie2...@gmail.com> > > wrote: > > > > > > On Wed, Oct 9, 2019 at 12:11 PM Andy Grove <andygrov...@gmail.com> > > wrote: > > > > > > > I'm very interested in helping to find a solution to this because we > > really > > > > do need integration tests for Rust to make sure we're compatible with > > other > > > > implementations... there is also the ongoing CI dockerization work > > that I > > > > feel is related. > > > > > > > > I haven't looked at the current integration tests yet and would > > appreciate > > > > some pointers on how all of this works (do we have docs?) or where to > > start > > > > looking. > > > > > > > I have a test in my latest PR: https://github.com/apache/arrow/pull/5523 > > > And here is the generated data: > > > https://github.com/apache/arrow-testing/pull/11 > > > As with program to generate these data, it's just a simple java program. > > > I'm not sure whether we need to integrate it into arrow. > > > > > > > > > > > I imagine the integration test could follow the approach that Renjie is > > > > outlining where we call Java to generate some files and then call Rust > > to > > > > parse them? > > > > > > > > Thanks, > > > > > > > > Andy. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tue, Oct 8, 2019 at 9:48 PM Renjie Liu <liurenjie2...@gmail.com> > > wrote: > > > > > > > > > Hi: > > > > > > > > > > I'm developing rust version of reader which reads parquet into arrow > > > > array. > > > > > To verify the correct of this reader, I use the following approach: > > > > > > > > > > > > > > > 1. Define schema with protobuf. > > > > > 2. Generate json data of this schema using other language with > > more > > > > > sophisticated implementation (e.g. java) > > > > > 3. Generate parquet data of this schema using other language with > > more > > > > > sophisticated implementation (e.g. java) > > > > > 4. Write tests to read json file, and parquet file into memory > > (arrow > > > > > array), then compare json data with arrow data. > > > > > > > > > > I think with this method we can guarantee the correctness of arrow > > > > reader > > > > > because json format is ubiquitous and their implementation are more > > > > stable. > > > > > > > > > > Any comment is appreciated. > > > > > > > > > > > > > > > > > > -- > > > Renjie Liu > > > Software Engineer, MVAD > > > > > -- > Renjie Liu > Software Engineer, MVAD
