[SPARK-21841] Spark SQL doesn't pick up column added in hive when table created with saveAsTable

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Incomplete
• Affects Version/s: 2.1.0, 2.2.0
• Component/s: SQL
• Labels: bulk-closed
• Assignee: Unassigned
• Reporter: Thomas Graves
• Created: 25/Aug/17 21:20
• Updated: 21/May/19 04:13
• Resolved: 21/May/19 04:13

Description

If you create a table in Spark sql but then you modify the table in hive to add a column, spark sql doesn't pick up the new column.

Basic example:

t1 = spark.sql("select ip_address from mydb.test_table limit 1")
t1.show()

+------------+
|  ip_address|
+------------+
|1.30.25.5|
+------------+

t1.write.saveAsTable('mydb.t1')

In Hive:
alter table mydb.t1 add columns (bcookie string)

t1 = spark.table("mydb.t1")
t1.show()
+------------+
|  ip_address|
+------------+
|1.30.25.5|
+------------+

It looks like its because spark sql is picking up the schema from spark.sql.sources.schema.part.0 rather then from hive.

Interestingly enough it appears that if you create the table differently like:
spark.sql("create table mydb.t1 select ip_address from mydb.test_table limit 1")
Run your alter table on mydb.t1
val t1 = spark.table("mydb.t1")

Then it works properly.

It looks like the difference is when it doesn't work spark.sql.sources.provider=parquet is set.
Its doing this from createDataSourceTable where provider is parquet.