Hive DATA-SCIENCE-OPTIMIZE Practice Questions (Page 3)

Questions 11–15

1. 11application · medium

   A Hive query performs a large aggregation over a fact table. The team notices that the query runs slowly because it processes rows one at a time. Which Hive feature should they enable to process multiple rows at once and improve CPU efficiency?

   • ABucketing
   • BMap-side join
   • CDynamic partitioning
   • DVectorization
   Reveal Solution Discussion Select an answer first
2. 12expert · hard

   A Hive table stores sensor readings. Each reading has a timestamp, a sensor ID, and a JSON payload with variable fields. The team wants to query specific fields from the JSON payload without parsing it manually in every query. Which Hive data type or feature should they use?

   • AUse a MAP<STRING, STRING> to represent the JSON fields.
   • BUse a STRUCT with all possible fields.
   • CUse a JSON SerDe to map the JSON payload to a Hive table with columns for each field.
   • DStore the payload as a STRING and use regexp_extract in queries.
   Reveal Solution Discussion Select an answer first
4. 13foundation · easy

   Which HiveQL statement is used to add a new column to an existing table?

   • AMODIFY TABLE table_name ADD COLUMN new_col INT;
   • BINSERT COLUMN new_col INT INTO table_name;
   • CUPDATE TABLE table_name ADD COLUMN new_col INT;
   • DALTER TABLE table_name ADD COLUMNS (new_col INT);
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5. 14expert · hard

   A Hive query joins a large fact table with a small dimension table (about 50 MB). The query runs as a reduce-side join, causing high network traffic. The team wants to reduce shuffle overhead. Which approach should they take?

   • AIncrease the number of reducers to distribute the join load.
   • BEnable hive.auto.convert.join and set hive.auto.convert.join.noconditionaltask.size to a value larger than the dimension table size.
   • CDisable vectorization to reduce memory pressure.
   • DUse a SORTED BY clause on the join key in both tables.
   Reveal Solution Discussion Select an answer first
6. 15expert · hard

   A Hive query is running slower than expected. The team suspects that the execution engine is not using all available resources. They check the YARN configuration and find that the cluster has 100 nodes, but the query is only using 10 containers. Which Hive or YARN setting is most likely to increase parallelism?

   • AIncrease hive.exec.reducers.bytes.per.reducer
   • BIncrease mapreduce.job.maps
   • CDecrease hive.exec.reducers.bytes.per.reducer
   • DSet hive.auto.convert.join to false
   Reveal Solution Discussion Select an answer first