@ravikumashi, if the table is altered by another user, the next Impala query likely to fail. Parquet stores the schema internally per column chunks, I assume changing this schema would mess up the addressing in the Parquet file, please see the file format details here. I can see two possible solutions, please note that I am unaware of the use-case: Option 1: Creating a new table with the new schema and re-creating the parquet files in Impala with INSERT INTO SELECT. At the end of this operation new parquet files with the new schema will be created in the new location. Option 2: With UNION the two schemata can be merged. For this the new/old data has to be split to two tables. Additionally, a VIEW could be created to hide this abstraction. Examples for the above two options, let me know if these are suitable for this use-case. # Test tables CREATE TABLE parquet_1 (id STRING, value DECIMAL(2,2)); INSERT INTO parquet_1 values ('1', 0.11); CREATE TABLE parquet_2 (id STRING, value DECIMAL(4,3)); INSERT INTO parquet_2 values ('2', 1.111); # Option 1 INSERT INTO TABLE parquet_2 SELECT * FROM parquet_1; # Option 2 SELECT * FROM parquet_1 UNION ALL SELECT * FROM parquet_2;
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