Major Description
This ODBC call is meant to allow you to determine FK relationships either from the PK side or from the FK side.
Hive only allows you to traverse from the FK side, trying it from the PK side leads to an NPE.
Example using the table "customer" from TPC-H with FKs defined in Hive:
=== Foreign Keys === Using table as foreign source (u'HIVE', u'tpch_bin_flat_orc_2', u'nation', u'n_nationkey', u'HIVE', u'tpch_bin_flat_orc_2', u'customer', u'c_nationkey', 1, 0, 0, u'custome r_c2', u'nation_c1', 0) Not using table as foreign source Got an error from the server for customer!
Compare: Postgres
=== Foreign Keys === Using table as foreign source (u'vagrant', u'public', u'nation', u'n_nationkey', u'vagrant', u'public', u'customer', u'c_nationkey', 1, 3, 3, u'customer_c_nationkey_fkey', u'nation_pkey', 7) Not using table as foreign source (u'vagrant', u'public', u'customer', u'c_custkey', u'vagrant', u'public', u'orders', u'o_custkey', 1, 3, 3, u'orders_o_custkey_fkey', u'customer_pkey', 7)
Note that Postgres allows traversal from either way. The traceback you get in the HS2 logs is this:
2016-12-04T21:08:55,398 ERROR [8998ca98-9940-49f8-8833-7c6ebd8c96a2 HiveServer2-Handler-Pool: Thread-53] metastore.RetryingHMSHandler: MetaEx ception(message:java.lang.NullPointerException) at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.newMetaException(HiveMetaStore.java:5785) at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.get_foreign_keys(HiveMetaStore.java:6474) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.hadoop.hive.metastore.RetryingHMSHandler.invokeInternal(RetryingHMSHandler.java:140) at org.apache.hadoop.hive.metastore.RetryingHMSHandler.invoke(RetryingHMSHandler.java:99) at com.sun.proxy.$Proxy25.get_foreign_keys(Unknown Source) at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.getForeignKeys(HiveMetaStoreClient.java:1596) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.invoke(RetryingMetaStoreClient.java:154) at com.sun.proxy.$Proxy26.getForeignKeys(Unknown Source) at org.apache.hive.service.cli.operation.GetCrossReferenceOperation.runInternal(GetCrossReferenceOperation.java:128) at org.apache.hive.service.cli.operation.Operation.run(Operation.java:324) at org.apache.hive.service.cli.session.HiveSessionImpl.getCrossReference(HiveSessionImpl.java:933) at org.apache.hive.service.cli.CLIService.getCrossReference(CLIService.java:411) at org.apache.hive.service.cli.thrift.ThriftCLIService.GetCrossReference(ThriftCLIService.java:738) at org.apache.hive.service.rpc.thrift.TCLIService$Processor$GetCrossReference.getResult(TCLIService.java:1617) at org.apache.hive.service.rpc.thrift.TCLIService$Processor$GetCrossReference.getResult(TCLIService.java:1602) at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39) at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39) at org.apache.hive.service.auth.TSetIpAddressProcessor.process(TSetIpAddressProcessor.java:56) at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:286) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.NullPointerException at org.apache.hive.common.util.HiveStringUtils.normalizeIdentifier(HiveStringUtils.java:919) at org.apache.hadoop.hive.metastore.ObjectStore$GetHelper.<init>(ObjectStore.java:2722) at org.apache.hadoop.hive.metastore.ObjectStore$GetListHelper.<init>(ObjectStore.java:2863) at org.apache.hadoop.hive.metastore.ObjectStore$11.<init>(ObjectStore.java:8455) at org.apache.hadoop.hive.metastore.ObjectStore.getForeignKeysInternal(ObjectStore.java:8455) at org.apache.hadoop.hive.metastore.ObjectStore.getForeignKeys(ObjectStore.java:8445) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.hadoop.hive.metastore.RawStoreProxy.invoke(RawStoreProxy.java:101) at com.sun.proxy.$Proxy24.getForeignKeys(Unknown Source) at org.apache.hadoop.hive.metastore.HiveMetaStore$HMSHandler.get_foreign_keys(HiveMetaStore.java:6465) ... 28 more