Explain Analyze raises "Unsupported logical plan: Analyze must be root of the plan"

[JosephWagner]

Describe the bug
Selecting from a partitioned parquet file with EXPLAIN ANALYZE raises this error:

Exception: DataFusion error: Internal error: Unsupported logical plan: Analyze must be root of the plan.
This issue was likely caused by a bug in DataFusion's code. Please help us to resolve this by filing a bug report in our issue tracker: https://github.com/apache/datafusion/issues

To Reproduce

import os
import shutil
import pyarrow as pa
import pyarrow.parquet as pq
import datafusion

BASE_DIR = "repro_analyze_bug"

if os.path.exists(BASE_DIR):
    shutil.rmtree(BASE_DIR)

partition_dir = f"{BASE_DIR}/a=1"
os.makedirs(partition_dir)

data_schema = pa.schema([
    ('b', pa.int32())
])

data_table = pa.Table.from_arrays(
    [[10, 20, 30, 40, 50, 60]],
    schema=data_schema
)
pq.write_table(data_table, f"{partition_dir}/data.parquet")

ctx = datafusion.SessionContext()

ctx.sql(f"""
    CREATE EXTERNAL TABLE my_table (
        b INT
    )
    STORED AS PARQUET 
    LOCATION '{BASE_DIR}/a=*/*.parquet'
    PARTITIONED BY (a INT)
""")


result = ctx.sql("EXPLAIN ANALYZE SELECT * FROM my_table")

# show will trigger the exception. collect will not
result.show()

# result output in ipython:
#[ins] In [2]: result
#Out[2]:
#    DataFrame()
#    +-------------------+-----------------------+
#    | plan_type         | plan                  |
#    +-------------------+-----------------------+
#    | Plan with Metrics | EmptyExec, metrics=[] |
#    |                   |                       |
#    +-------------------+-----------------------+

Expected behavior
I would expect no exception, and a query plan to be displayed

Additional context
The table is selectable but appears to have 0 rows. I'm not sure why.

[ins] In [7]: ctx.sql("select count(*) from my_table")
Out[7]:
DataFrame()
+----------+
| count(*) |
+----------+
| 0        |
+----------+

[timsaucer]

Still investigating, but for an immediate work around you can replace

result = ctx.sql("EXPLAIN ANALYZE SELECT * FROM my_table")
result.show() 

with:

ctx.sql("SELECT * FROM my_table").explain()

or alternatively

print(ctx.sql("EXPLAIN ANALYZE SELECT * FROM my_table"))

[timsaucer]

I believe there is a second issue of why ctx.sql("SELECT * FROM my_table").show() has no rows, but that is a different issue and I'd need to see if that's an upstream issue or something in df-python.

[timsaucer]

I believe the reason this issue fails is because we have .limit(0, Some(num)) appended during a show(). We could do a check on the logical plan and if it's an analyze bypass the limit.

[timsaucer]

I believe there is a second issue of why ctx.sql("SELECT * FROM my_table").show() has no rows, but that is a different issue and I'd need to see if that's an upstream issue or something in df-python.

Actually this just needs the path corrected to

LOCATION '{BASE_DIR}'