Hi Yu, glad to hear that you are considering contributing to Impala! As others have mentioned before, I'd strongly recommend starting with a smaller task to get accustomed our development workflows.
I'm happy to help with finding a suitable task. For example, you might find this JIRA interesting: https://issues.apache.org/jira/browse/IMPALA-5016 Please do reach out if I can help. Alex On Tue, Apr 18, 2017 at 10:55 AM, Alexander Behm <[email protected]> wrote: > The existing attempt used the Rapidjson library to do the parsing. > Unfortunately, the Rapidjson API is not very convenient for Impala because > it returns typed data, i.e., it internally converts to > float/double/int/whatever which is problematic for decimal (among others). > Ideally, we would use the same Impala code to convert data types from > strings. > > On Tue, Apr 18, 2017 at 9:27 AM, Tim Armstrong <[email protected]> > wrote: > >> Seems like useful functionality that would be great to have in Impala. >> There was an earlier attempt to do this that didn't make it in - I'm not >> sure that the approach was quite right: >> https://gerrit.cloudera.org/#/c/1201/1 . I'm not sure what the exact >> problems were but I remember we didn't think it was quite the right >> approach. >> >> I think we'd need to talk through a design first because there are a lot >> of >> considerations and we want to make sure to get it right. I had some >> initial >> questions that I'd want to think through before adding a JSON scanner. >> >> - What JSON does it accept? >> - How do we declare a table schema and map it to the JSON >> - How does it handle missing or extra fields - does it just return null >> or drop the fields? What if the field type is wrong? >> - How do the numeric types work? JSON only supports floating point, but >> I think many people would like to store higher-precision decimal or >> 64-bit >> integer types (which is technically outside of the JSON standard). >> - Will it support codegen? If not, is it written in a way that allows >> it >> in future? >> >> Cheers, >> Tim >> >> - Tim >> >> On Tue, Apr 18, 2017 at 8:52 AM, Jim Apple <[email protected]> wrote: >> >> > On Mon, Apr 17, 2017 at 8:02 PM, yu feng <[email protected]> wrote: >> > >> > > Hi impala community: >> > > I am Newly join to Impala, >> > >> > >> > Welcome! >> > >> > I want to know what is the attitude of impala >> > > community for supporting json format. >> > >> > >> > I am in favor of it. I am only one person, though - anybody else object >> to >> > JSON support? >> > >> > If this match the roadmap, maybe I >> > > can make some contribution. >> > > >> > >> > I do not recall much talk about Apache Impala's roadmap since we joined >> the >> > ASF. Perhaps I missed a thread about it? >> > >> > >
