If you read data from Snowflake in Spark using e.g. spark.read.jdbc it will be slow. This is because the data is loaded in a single step, and is therefore loaded by a single executor.

You need to somehow distributing the query among the spark executors, and assign each executor to read a subset of the result, eg. by adding WHERE conditions or limit-offset clauses, and distribute them among the executors.

JDBC method has also option to supply following information partitionColumn, lowerBound, upperBound, and numPartitions , then you can paralelize it.

Another way is to sync data into DeltaLake and run your query against delta table.

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UPDATE: there is also one more way but would require redesign on Snoflake end -> to create table in Snowflake as External Iceberg table and connect your Databricks job to Iceberg but that might be overkill.

Thanks !!