[ https://issues.apache.org/jira/browse/DRILL-5088?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15820028#comment-15820028 ]
ASF GitHub Bot commented on DRILL-5088: --------------------------------------- Github user gparai commented on a diff in the pull request: https://github.com/apache/drill/pull/702#discussion_r95719700 --- Diff: contrib/storage-mongo/src/main/java/org/apache/drill/exec/store/mongo/MongoGroupScan.java --- @@ -503,7 +505,9 @@ public ScanStats getScanStats() { long numDocs = collection.count(); float approxDiskCost = 0; if (numDocs != 0) { - String json = collection.find().first().toJson(); + final DocumentCodec codec = --- End diff -- Please add a comment to describe the need for the codec along with the example from the bug. > Error when reading DBRef column > ------------------------------- > > Key: DRILL-5088 > URL: https://issues.apache.org/jira/browse/DRILL-5088 > Project: Apache Drill > Issue Type: Bug > Components: Execution - Data Types > Environment: drill 1.9.0 > mongo 3.2 > Reporter: Guillaume Champion > Assignee: Chunhui Shi > > In a mongo database with DBRef, when a DBRef is inserted in the first line of > a mongo's collection drill query failed : > {code} > 0: jdbc:drill:zk=local> select * from mongo.mydb.contact2; > Error: SYSTEM ERROR: CodecConfigurationException: Can't find a codec for > class com.mongodb.DBRef. > {code} > Simple example to reproduce: > In mongo instance > {code} > db.contact2.drop(); > db.contact2.insert({ "_id" : ObjectId("582081d96b69060001fd8938"), "account" > : DBRef("contact", ObjectId("999cbf116b69060001fd8611")) }); > {code} > In drill : > {code} > 0: jdbc:drill:zk=local> select * from mongo.mydb.contact2; > Error: SYSTEM ERROR: CodecConfigurationException: Can't find a codec for > class com.mongodb.DBRef. > [Error Id: 2944d766-e483-4453-a706-3d481397b186 on Analytics-Biznet:31010] > (state=,code=0) > {code} > If the first line doesn't contain de DBRef, drill will querying correctly : > In a mongo instance : > {code} > db.contact2.drop(); > db.contact2.insert({ "_id" : ObjectId("582081d96b69060001fd8939") }); > db.contact2.insert({ "_id" : ObjectId("582081d96b69060001fd8938"), "account" > : DBRef("contact", ObjectId("999cbf116b69060001fd8611")) }); > {code} > In drill : > {code} > 0: jdbc:drill:zk=local> select * from mongo.mydb.contact2; > +--------------------------------------+---------------------------------------------------------------+ > | _id | account > | > +--------------------------------------+---------------------------------------------------------------+ > | {"$oid":"582081d96b69060001fd8939"} | {"$id":{}} > | > | {"$oid":"582081d96b69060001fd8938"} | > {"$ref":"contact","$id":{"$oid":"999cbf116b69060001fd8611"}} | > +--------------------------------------+---------------------------------------------------------------+ > 2 rows selected (0,563 seconds) > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)