Using Hive tables can improve spark read performance
I am a data engineer at Tesco and this blog is part of a mentoring process to track the progress of my career development journey.
Using Hive tables can indeed improve Spark read performance, especially when leveraging optimizations like predicate pushdown, column pruning, and partition pruning.
Example:
Create Sample Data and Hive Table
import time
# Create a sample DataFrame
data = [(i, f"name_{i}") for i in range(1000000)]
columns = ["id", "name"]
df = spark.createDataFrame(data, columns)
# Save DataFrame as a Hive table
df.write.mode("overwrite").saveAsTable("mydb.sample_hive_table")
Measure Read Performance without Hive Table
# Measure time to read DataFrame
start_time = time.time()
df = spark.read.format("parquet").load("/data/mydb.db/sample_hive_table")
df.count()
end_time = time.time()
print(f"Time taken to read DataFrame: {end_time - start_time} seconds")
Time taken to read DataFrame: 1.2805027961730957 seconds
Measure Read Performance with Hive Table
# Measure time to read Hive table
# Measure time to read Hive table
start_time = time.time()
hive_df = spark.sql("SELECT * FROM mydb.sample_hive_table")
hive_df.count()
end_time = time.time()
print(f"Time taken to read Hive table: {end_time - start_time} seconds")
Time taken to read Hive table: 0.5941483974456787 seconds
By comparing the time taken to read data directly from a DataFrame versus a Hive table, you can observe the performance improvements (1.3s vs. 0.6s). Typically, Hive tables offer better performance due to these optimizations:
Predicate Pushdown - When using Hive tables, Spark can push down filters to the storage layer, reducing the amount of data read. Column Pruning - Only the necessary columns are read, reducing I/O. Partition Pruning - Only relevant partitions are scanned, improving read performance1.