CODEWITHSUNDEEP
hadoophiveschemaorc
Adarsh
Adarsh

Reputation: 41

ORC schema evolution

After going through a sample ORC file itself I came to know that ORC file format does not store any column information, in fact all the column names will be replaced by _c0 to _cn, in such scenario how a proper schema evolution can be achieved for ORC tables?

Upvotes: 4

Views: 2259

Answers (1)

Gaurang Shah
Gaurang Shah

Reputation: 12920

ORC format does not store any information about hive column names. There was a bug which was storing column information if ORC file were created using PIG. You can find the details below

https://issues.apache.org/jira/browse/HIVE-7189

I think ORC file format (and other) rely on Hive Metastore for this information. if you will run describe formatted <table_name>, you will get the schema information.

something like 

# col_name              data_type               comment

name                    string

Upvotes: 1

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