Truncate delta table in Databricks using python

Question

Delta table delete operation is given here for Python and SQL, and truncate using SQL is given here. But I cannot find the documentation for Python truncate table.

How to do it for delta table in Databricks?

Muriel

Answer 1

Not everything is exposed as a function for Python or Java/Scala. Some operations are SQL-only, like OPTIMIZE for example. If you want to truncate table, you have two choices:

1. Use

spark.sql("TRUNCATE TABLE <name>")

or

spark.sql("TRUNCATE TABLE delta.`<path>`")

2. Emulate truncate with read + write empty dataframe in overwrite mode:

df = spark.read.format("delta").load("<path>")
df.limit(0).write.mode("overwrite").format("delta").save("<path>")

Adorable

Answer 2

I faced the below issue Azure Synapse Analytics when working in Synapse notebooks.

AnalysisException: Table does not support truncates

Truncate operation is not supported in delta lake tables because when we create a delta table in Synapse, it's doesn't create an actual physical table, but it creates files(parquet) in ADLS. You can delete the table in the below 2 ways

1. Use the DELETE query as below

   query = "DELETE FROM tablename" spark.sql(query)

2. Delete the parquet files from the 'warehouse' folder in ADLS.

Kruter