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doris/be
daidai 5d02c48715 [feature](hive)Support reading renamed Parquet Hive and Orc Hive tables. (#38432) (#38809)
bp #38432 

## Proposed changes
Add `hive_parquet_use_column_names` and `hive_orc_use_column_names`
session variables to read the table after rename column in `Hive`.

These two session variables are referenced from
`parquet_use_column_names` and `orc_use_column_names` of `Trino` hive
connector.

By default, these two session variables are true. When they are set to
false, reading orc/parquet will access the columns according to the
ordinal position in the Hive table definition.

For example:
```mysql
in Hive :
hive> create table tmp (a int , b string) stored as parquet;
hive> insert into table tmp values(1,"2");
hive> alter table tmp  change column  a new_a int;
hive> insert into table tmp values(2,"4");

in Doris :
mysql> set hive_parquet_use_column_names=true;
Query OK, 0 rows affected (0.00 sec)

mysql> select  * from tmp;
+-------+------+
| new_a | b    |
+-------+------+
|  NULL | 2    |
|     2 | 4    |
+-------+------+
2 rows in set (0.02 sec)

mysql> set hive_parquet_use_column_names=false;
Query OK, 0 rows affected (0.00 sec)

mysql> select  * from tmp;
+-------+------+
| new_a | b    |
+-------+------+
|     1 | 2    |
|     2 | 4    |
+-------+------+
2 rows in set (0.02 sec)
```

You can use `set
parquet.column.index.access/orc.force.positional.evolution = true/false`
in hive 3 to control the results of reading the table like these two
session variables. However, for the rename struct inside column parquet
table, the effects of hive and doris are different.
2024-08-05 09:06:49 +08:00
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