Auotoloader-"cloudFiles.backfillInterval"

[Kiranrathod]

1. How to use cloudFiles.backfillInterval option in a notebook?
2. Does It need to be any set of the property?
3. Where is exactly placed readstream portion of the code or writestream portion of the code?
4. Do you have any sample code?
5. Where we find cloudFiles.backfillInterval logs?

[Kaniz]

Hi @Kiranrathod , To use the cloudFiles.backfillInterval option in a Databricks Notebook, follow these steps:

1. Set the cloudFiles.backfillInterval option while configuring your DataStreamWriter. For example, to set it to 300 seconds (5 minutes):

.writeStream \
.option("cloudFiles.backfillInterval", 300) \

2. The readStream part of your code reads data from an external source, such as Kafka, creating a streaming DataFrame. The writeStream part writes this streaming DataFrame to an external sink, like Azure Blob storage in Avro format.

3. The cloudFiles.backfillInterval option specifies the waiting time in seconds before triggering a backfill for failed batches.

4. To check logs related to cloudFiles.backfillInterval, you can inspect the Databricks cluster driver logs. Look for any errors or warnings related to backfill attempts for failed tasks. You can also check the job status for any errors where backfill has been triggered.

By following these steps, you can effectively configure and monitor the cloudFiles.backfillInterval option in your Databricks notebook.

[Kiranrathod]

Hi @Kaniz , Can you please answer follows question ,
1.Is the following code correct for specifying the .option("cloudFiles.backfillInterval", 300)?
df = spark.readStream.format("cloudFiles") \
.option("cloudFiles.format", "csv") \
.option("cloudFiles.schemaLocation", f"dbfs:/FileStore/xyz/back_fill_option/schema/backfill")\
.load(f"dbfs:/FileStore/xyz/back_fill_option/source")

df.writeStream \
.format("delta") \
.option("cloudFiles.backfillInterval", 300) \
.trigger(processingTime='3 minutes') \
.option("checkpointLocation", f"dbfs:/FileStore/xyz/back_fill_option/checkpoint/backfill") \
.table("back_fill_option")

2.If the autoloader streaming process begins at "2023-11-01T01:00:00" and you set .option("cloudFiles.backfillInterval", 300), does this mean that the backfillInterval will trigger at "2023-11-01T01:05:00"?
3.When you pass the option .trigger(processingTime='3 minutes'), it triggers the process every 3 minutes. If you also set backfillInterval to 2 minutes, does that mean the backfillInterval triggers every 2 minutes?
4.When you set the property processingTime to a value greater than backfillInterval, does that mean the backfillInterval runs before the processingTime interval elapses?
5.How can you verify the functionality of the "cloudFiles.backfillInterval" to ensure it is working correctly with the provided autoloader code?

[Kiranrathod]

1.Is the following code correct for specifying the  .option("cloudFiles.backfillInterval", 300)?
df = spark.readStream.format("cloudFiles") \
.option("cloudFiles.format", "csv") \
.option("cloudFiles.schemaLocation", f"dbfs:/FileStore/xyz/back_fill_option/schema/backfill")\
.load(f"dbfs:/FileStore/xyz/back_fill_option/source")

df.writeStream \
.format("delta") \
.option("cloudFiles.backfillInterval", 300) \
.trigger(processingTime='3 minutes') \
.option("checkpointLocation", f"dbfs:/FileStore/xyz/back_fill_option/checkpoint/backfill") \
.table("back_fill_option")

2.If the autoloader streaming process begins at "2023-11-01T01:00:00" and you set .option("cloudFiles.backfillInterval", 300), does this mean that the backfillInterval will trigger at "2023-11-01T01:05:00"?
3.When you pass the option .trigger(processingTime='3 minutes'), it triggers the process every 3 minutes. If you also set backfillInterval to 2 minutes, does that mean the backfillInterval triggers every 2 minutes?
4.When you set the property processingTime to a value greater than backfillInterval, does that mean the backfillInterval runs before the processingTime interval elapses?
5.How can you verify the functionality of the "cloudFiles.backfillInterval" to ensure it is working correctly with the provided autoloader code?