Parquet ColumnIndex for null columns is written even when statistics are disabled #6010
Description
Describe the bug
Inspection of the page index metadata shows that the ColumnIndex for columns that are all nulls is written regardless of the setting of GenericColumnWriter::statistics_enabled.
To Reproduce
In the output below, the c_login column has a ColumnIndex entry as well as the expected OffsetIndex. No other columns do.
% target/debug/parquet-rewrite -i parquet-testing/data/delta_byte_array.parquet -o test.parquet --statistics-enabled none
% pqmeta -i test.parquet Rowgroup 0: num_rows:1000
-----------------------------------------------------------
c_customer_id
--------------------------------------------------
OffsetIndex:
page0: offset:20023 compressed_size:1280 first_row_index:0 var_bytes:16000
c_salutation
--------------------------------------------------
OffsetIndex:
page0: offset:21404 compressed_size:473 first_row_index:0 var_bytes:3145
c_first_name
--------------------------------------------------
OffsetIndex:
page0: offset:26992 compressed_size:1325 first_row_index:0 var_bytes:5650
c_last_name
--------------------------------------------------
OffsetIndex:
page0: offset:35182 compressed_size:1323 first_row_index:0 var_bytes:6011
c_preferred_cust_flag
--------------------------------------------------
OffsetIndex:
page0: offset:36567 compressed_size:235 first_row_index:0 var_bytes:971
c_birth_country
--------------------------------------------------
OffsetIndex:
page0: offset:39532 compressed_size:1097 first_row_index:0 var_bytes:8458
c_login
--------------------------------------------------
OffsetIndex:
page0: offset:40685 compressed_size:26 first_row_index:0 var_bytes:0
ColumnIndex: boundary_order:ASCENDING
page0: null_page:True min_val: max_val: null_count:1000
c_email_address
--------------------------------------------------
OffsetIndex:
page0: offset:71199 compressed_size:1334 first_row_index:0 var_bytes:26562
c_last_review_date
--------------------------------------------------
OffsetIndex:
page0: offset:76368 compressed_size:1200 first_row_index:0 var_bytes:6825
Expected behavior
Null columns should not have a ColumnIndex present when page statistics are not enabled.
Additional context