This article explains how table locking works in Hive by running a series hive commands and their outputs. To do this, I have created two simple tables in my small cluster called “test” and “test_partitioned”. Initially, when no query is running against the “test” table, the table should have no …
Hive supports a couple of ways to read JSON data, however, I think the easiest way is to use custom JsonSerDe library. The article illustrated how to use this library to query JSON data stored in HDFS using Hive. 1. Download binary jar file based on your CDH version at: …
Today I have discovered a bug in Hive, that when user submits an “INSERT OVERWRITE” query with dynamic partitioning, Hive does not lock the underlining table “exclusively”, rather it only applies “shared” lock. To confirm the problem, I created a simple table: Then I issued a dynamic partitioning query: And …
Beeline will return non-zero exit code on failure in the following CDH versions 5.2.2 onwards. The returned exit code simply means the number of errors occurred during beeline’s execution. So for example, the following command will result the exit code of 2 because the first two “show” command will fail …
When Hive tries to “INSERT OVERWRITE” to a partition of an external table under existing directory, depending on whether the partition definition already exists in the metastore or not, Hive will behave differently: 1) if partition definition does not exist, it will not try to guess where the target partition …
My new Snowflake Blog is now live. I will not be updating this blog anymore but will continue with new contents in the Snowflake world!