massdosage commented on a change in pull request #1837:
URL: https://github.com/apache/iceberg/pull/1837#discussion_r531647679
##########
File path: site/docs/hive.md
##########
@@ -84,7 +84,32 @@ You should now be able to issue Hive SQL `SELECT` queries
using the above table
SELECT * from table_b;
```
+#### Using Hadoop Catalog
+Iceberg tables created using `HadoopCatalog` are stored entirely in a
directory in a filesytem like HDFS.
+
+##### Create an Iceberg table
+The first step is to create an Iceberg table using the Spark/Java/Python API
and `HadoopCatalog`. For the purposes of this documentation we will assume that
the table is called `database_a.table_c` and that the table location is
`hdfs://some_path/database_a/table_c`.
+
+##### Create a Hive table
+Now overlay a Hive table on top of this Iceberg table by issuing Hive DDL like
so:
+```sql
+CREATE EXTERNAL TABLE table_a
+STORED BY 'org.apache.iceberg.mr.hive.HiveIcebergStorageHandler'
+LOCATION 'hdfs://some_bucket/some_path/database_a/table_c';
+```
+
+#### Query the Iceberg table via Hive
+TODO: why does below work if no config settings are set in Hive but fails if
we add `set iceberg.mr.catalog=hadoop` like the code suggests we need to do?
Review comment:
> @massdosage: Would it be a problem with the warehouse path for the
HadoopCatalog: "location=/tmp/iceberg-test-hadoop-tables"? My guess is that
this should be "hdfs://host/tmp/iceberg-test-hadoop-tables", and so the
HadoopCatalog is not able to read the table data.
OK, this jogged me into realising that I also need to set
"iceberg.mr.catalog.hadoop.warehouse.location". If I do that then it works!
Interestingly enough it works with the table location set like you suggested
and also with the full path like I had. Anyway, I'll update the document
accordingly to show at least how it can be done currently. Thanks!
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