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Description
Currently, the Delta Lake connector not write column statistics for row type.
Here is minimal reproduce step in Delta Lake connector
trino:tpch> CREATE TABLE t (id int, v1 int, r row(n1 int, n2 row(n3 int, n4 int)));
CREATE TABLE
trino:tpch> INSERT INTO t values (1, 1, row(1, row(1,1)));
INSERT: 1 row
Query 20250414_080903_00003_2ffn7, FINISHED, 2 nodes
Splits: 15 total, 15 done (100.00%)
2.15 [0 rows, 0B] [0 rows/s, 0B/s]
trino:tpch> select * from t;
id | v1 | r
----+----+-------------------------
1 | 1 | {n1=1, n2={n3=1, n4=1}}
(1 row)
Query 20250414_080909_00004_2ffn7, FINISHED, 1 node
Splits: 1 total, 1 done (100.00%)
0.85 [1 rows, 691B] [1 rows/s, 810B/s]
trino:tpch> show stats for (select * from t);
column_name | data_size | distinct_values_count | nulls_fraction | row_count | low_value | high_value
-------------+-----------+-----------------------+----------------+-----------+-----------+------------
id | NULL | 1.0 | 0.0 | NULL | 1 | 1
v1 | NULL | 1.0 | 0.0 | NULL | 1 | 1
r | NULL | NULL | NULL | NULL | NULL | NULL
NULL | NULL | NULL | NULL | 1.0 | NULL | NULL
(4 rows)
in log file:
"stats":"{\"numRecords\":1,\"minValues\":{\"id\":1,\"v1\":1},\"maxValues\":{\"id\":1,\"v1\":1},\"nullCount\":{\"id\":0,\"v1\":0}}"