I now extended the AvroFormatTest-Suite by two unit tests that show that * Flattening of primitive array works as expected * Flattening of arrays of records does not work properly
I spent some time trying to find the reason but it's my first contact with the drill-codebase. Is the recommended way of making this unit test available still to attach a patch in an issue or is a pull-request also an option? In the context of the recent avro maturity discussion I would love to fix this error myself but I would need some hints what goes wrong there internally. Johannes On Fri, Mar 25, 2016 at 10:50 PM, Johannes Schulte < [email protected]> wrote: > Hi Stefan, hi Jacques, thanks for going after this - I almost resignated > but know i think it was because i accessed the data over jdbc with squirrel > and got irritated by the unknown type column there. nonetheless, if the > schema looks like this: > > > { > "type" : "record", > "name" : "MainRecord", > "namespace" : "drizz.WriteAvroTestFileForDrill$", > "fields" : [ { > "name" : "elements", > "type" : { > "type" : "array", > "items" : { > "type" : "record", > "name" : "NestedRecord", > "fields" : [ { > "name" : "field1", > "type" : "int" > } ] > }, > "java-class" : "java.util.List" > } > } ] > } > > and the contents looks like this (according to avro tojson command line > utility) > > > {"elements":[{"field1":0},{"field1":1},{"field1":2},{"field1":3},{"field1":4},{"field1":5},{"field1":6},{"field1":7},{"field1":8},{"field1":9}]} > > {"elements":[{"field1":0},{"field1":1},{"field1":2},{"field1":3},{"field1":4},{"field1":5},{"field1":6},{"field1":7},{"field1":8},{"field1":9}]} > > a query like > > select flatten(elements) from > dfs.`/Users/j.schulte/data/avro-drill/no-union/`; > > yields exactly two rows: > +---------------+ > | EXPR$0 | > +---------------+ > | {"field1":9} | > | {"field1":9} | > +---------------+ > > as if only the last element in the array would survive. > > Thanks for your help so far.. > > On Fri, Mar 25, 2016 at 5:45 PM, Stefán Baxter <[email protected]> > wrote: > >> Johannes, Jacques is right. >> >> I only tested the flattening of maps and not the flattening of >> list-of-maps. >> >> -Stefan >> >> On Fri, Mar 25, 2016 at 4:12 PM, Jacques Nadeau <[email protected]> >> wrote: >> >> > I think there is some incorrect information and confusion in this >> thread. >> > Could you please share a piece of sample data and a specific query? The >> > error message shown in your original email is suggesting that you were >> > trying to flatten a map rather than an array of maps. Flatten is for >> arrays >> > only. The arrays can have scalars or complex objects in them. >> > >> > -- >> > Jacques Nadeau >> > CTO and Co-Founder, Dremio >> > >> > On Fri, Mar 25, 2016 at 2:00 AM, Johannes Schulte < >> > [email protected]> wrote: >> > >> > > Hi Stefan, >> > > >> > > thanks for this information - so it seems that there is currently no >> way >> > of >> > > accessing nested rich objects with drill; I somehow got that wrong >> from >> > the >> > > documentation... >> > > >> > > Cheers, >> > > Johannes >> > > >> > > On Thu, Mar 24, 2016 at 2:14 PM, Stefán Baxter < >> > [email protected]> >> > > wrote: >> > > >> > > > FYI: flattening of embedded structures is not supported in Parquet >> > > either. >> > > > >> > > > Regards, >> > > > -Stefan >> > > > >> > > > On Wed, Mar 23, 2016 at 8:51 PM, Johannes Schulte < >> > > > [email protected]> wrote: >> > > > >> > > > > Hi Stefan, >> > > > > >> > > > > thanks for your response and the link to your udf repository, >> it's a >> > > good >> > > > > reference. I tried drill 1.6, the data is an array of complex >> objects >> > > > > though. I will try to setup a drill dev environment and see if i >> can >> > > > modify >> > > > > the tests to fail. >> > > > > >> > > > > Johannes >> > > > > >> > > > > On Wed, Mar 23, 2016 at 8:13 PM, Stefán Baxter < >> > > > [email protected]> >> > > > > wrote: >> > > > > >> > > > > > FYI. this seems to be working in 1.6, at least on the Avro data >> > that >> > > we >> > > > > > have. >> > > > > > >> > > > > > On Wed, Mar 23, 2016 at 6:59 PM, Stefán Baxter < >> > > > > [email protected]> >> > > > > > wrote: >> > > > > > >> > > > > > > Hi again, >> > > > > > > >> > > > > > > What version of Drill are you using? >> > > > > > > >> > > > > > > Regards, >> > > > > > > - Stefán >> > > > > > > >> > > > > > > On Wed, Mar 23, 2016 at 4:49 PM, Stefán Baxter < >> > > > > > [email protected]> >> > > > > > > wrote: >> > > > > > > >> > > > > > >> Hi Johannes, >> > > > > > >> >> > > > > > >> As great as Drill is the Avro plugin has been a source of >> > > > frustration >> > > > > > for >> > > > > > >> us @activitystream. >> > > > > > >> >> > > > > > >> We have a small UDF library [1] (apache licensed) which >> > contains a >> > > > > > >> function can return an array (List<String>) from Avro as a >> CSV >> > > list. >> > > > > > >> >> > > > > > >> You could use that to roll your own or provide me with a >> small >> > > > sample >> > > > > > and >> > > > > > >> I can create a custom flatten function for you. >> > > > > > >> >> > > > > > >> The best would be to wait for a fix but this can potentially >> get >> > > you >> > > > > out >> > > > > > >> of a rough spot. >> > > > > > >> >> > > > > > >> [1] https://github.com/activitystream/asdrill >> > > > > > >> >> > > > > > >> Regards, >> > > > > > >> -Stefán >> > > > > > >> >> > > > > > >> On Wed, Mar 23, 2016 at 9:05 AM, Johannes Schulte < >> > > > > > >> [email protected]> wrote: >> > > > > > >> >> > > > > > >>> Hi, >> > > > > > >>> >> > > > > > >>> when trying to read simple avro arrays with select >> > flatten(array) >> > > > > from >> > > > > > >>> dfs... i get the exception >> > > > > > >>> >> > > > > > >>> SQL Query Error: SYSTEM ERROR: ClassCastException: Cannot >> cast >> > > > > > >>> org.apache.drill.exec.vector.complex.MapVector to >> > > > > > >>> org.apache.drill.exec.vector.complex.RepeatedValueVector >> > > > > > >>> ^ >> > > > > > >>> >> > > > > > >>> The type of the array is said to be <UnknownType (2,002)> >> > > > > > >>> >> > > > > > >>> Is this the expected behaviour? The documentation mostly >> talsk >> > > > about >> > > > > > json >> > > > > > >>> and parquet complex types and i wonder if the avro storage >> > plugin >> > > > > > behaves >> > > > > > >>> differently. >> > > > > > >>> >> > > > > > >>> Thanks, >> > > > > > >>> >> > > > > > >>> Johannes >> > > > > > >>> >> > > > > > >> >> > > > > > >> >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > >> > >
