topic Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429 in Data Engineering

Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

gregahren — Tue, 04 Feb 2025 07:41:59 GMT

Hi everyone,

We are trying to use synapse spark connector https://learn.microsoft.com/en-us/fabric/data-engineering/spark-data-warehouse-connector

We have some TSQL queries that we are executing in parallel. Previously those queries were written in spark sql. Now we would like to use tsql with the connector.

But after some queries run I get this errors: `An error occurred while calling o55682.synapsesql.
: com.microsoft.spark.fabric.tds.error.FabricSparkTDSHttpFailure: Artifact ID inquiry attempt failed with error code 429. Request Id - .`

Is there some limitation on how many queries we can run in the session? And how to solve this?

Thanks for your help

Re: Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

nilendraFabric — Tue, 04 Feb 2025 10:35:23 GMT

Hello gregahren

Could you please share more details about the usecase.

Re: Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

gregahren — Tue, 04 Feb 2025 11:43:03 GMT

Yes of course.

We are running some queries in parallel threads when processing our data, which works for sparks sql, when for tsql it throws 429 errors. I quickly added an example you can run in notebook so you can see where the issue is:

import com.microsoft.spark.fabric from com.microsoft.spark.fabric.Constants import Constants from concurrent.futures import ThreadPoolExecutor WORKSPACE_ID = "your_workspace_id" LAKEHOUSE_NAME = "lakehouse_name" def run_spark_multiple_threads( target_function, args_list, number_of_threads = 8 ): with ThreadPoolExecutor(number_of_threads) as pool: futures = [pool.submit(target_function, *args) for args in args_list] results = [future.result() for future in futures] return results def run_tsql(i): df = ( spark.read.option( Constants.WorkspaceId, WORKSPACE_ID, ) .option( Constants.DatabaseName, LAKEHOUSE_NAME, ) .synapsesql("""SELECT 1 as Temp""") ) print(i, df.count()) def run_sparksql(i): df = spark.sql("""SELECT 1 as Temp""") print(i, df.count()) run_spark_multiple_threads( run_sparksql, [(i,) for i in range(100)], number_of_threads=8 ) print("done with spark sql") run_spark_multiple_threads( run_tsql, [(i,) for i in range(100)], number_of_threads=8 ) print("done with tsql")

Here you will see that spark sql finishes normally for 100 queries, when tsql stops working after 50 or some queries. I believe there is rate limit 50req/50sec set, but its not mentioned in limitations of Spark connector for Microsoft Fabric Data Warehouse.

If you need more info still please let me know.

Re: Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

nilendraFabric — Tue, 04 Feb 2025 12:22:08 GMT

Thanks for sharing the details gregahren

which F SKU you are on?

Here are my thoughts

The SQL analytics endpoint (used for T‑SQL queries) in Fabric Data Warehouse imposes throttling rules (or smoothing policies) that can lead to errors like 429 when too many requests are submitted concurrently over a short period. This mechanism is intended to manage resource saturation during peak usage.

• While it appears your workload exceeds an unofficial threshold (around 50 requests per 50 seconds), this limit isn’t formally documented as a “50req/50sec” rule. Instead, it’s part of the broader “compute capacity smoothing and throttling” policies that control background operations and ask users to manage concurrency when using T‑SQL via the connector

https://learn.microsoft.com/bs-latn-ba/fabric/data-warehouse/compute-capacity-smoothing-throttling

hope this is helpful.

if yes please accept the answer

Re: Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

gregahren — Tue, 04 Feb 2025 12:45:56 GMT

Thank you for your answer, I guess we will just have to take those limits into account.

We are on F4 capacity currently.

Thanks for your quick answer again!

Re: Spark Connector for Data Warehouse - Fails with FabricSparkTDSHttpFailure 429

nilendraFabric — Tue, 04 Feb 2025 12:48:32 GMT

gregahren Glad it was helpful. Could you please accept the solution as this will be beneficial for community to find the right information quickly