[SPARK-54117][SS] Throw better error to indicate that TWS is only supported with RocksDB state store provider

common/utils/src/main/resources/error/error-conditions.json

@@ -6554,6 +6554,11 @@
           "State TTL with <stateStoreProvider> is not supported. Please use RocksDBStateStoreProvider."
         ]
       },
+      "STORE_BACKEND_NOT_SUPPORTED_FOR_TWS" : {
+        "message" : [
+          "Store backend <stateStoreProvider> is not supported by TransformWithState operator. Please use RocksDBStateStoreProvider."
+        ]
+      },
       "TABLE_OPERATION" : {
         "message" : [
           "Table <tableName> does not support <operation>. Please check the current catalog and namespace to make sure the qualified table name is expected, and also check the catalog implementation which is configured by \"spark.sql.catalog\"."

sql/core/src/main/scala/org/apache/spark/sql/execution/python/streaming/TransformWithStateInPySparkExec.scala

@@ -181,6 +181,7 @@ case class TransformWithStateInPySparkExec(
    */
   override protected def doExecute(): RDD[InternalRow] = {
     metrics
+    validateStateStoreProvider()
 
     if (!hasInitialState) {
       if (isStreaming) {

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/operators/stateful/transformwithstate/TransformWithStateExec.scala

@@ -374,6 +374,7 @@ case class TransformWithStateExec(
     metrics // force lazy init at driver
 
     validateTimeMode()
+    validateStateStoreProvider()
 
     if (hasInitialState) {
       val storeConf = new StateStoreConf(session.sessionState.conf)

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/operators/stateful/transformwithstate/TransformWithStateExecBase.scala

@@ -24,7 +24,8 @@ import org.apache.spark.sql.catalyst.plans.physical.Distribution
 import org.apache.spark.sql.execution.{BinaryExecNode, SparkPlan}
 import org.apache.spark.sql.execution.streaming.operators.stateful.{StatefulOperatorCustomMetric, StatefulOperatorCustomSumMetric, StatefulOperatorPartitioning, StateStoreWriter, WatermarkSupport}
 import org.apache.spark.sql.execution.streaming.operators.stateful.transformwithstate.statefulprocessor.ImplicitGroupingKeyTracker
-import org.apache.spark.sql.execution.streaming.state.{OperatorStateMetadata, TransformWithStateUserFunctionException}
+import org.apache.spark.sql.execution.streaming.state.{OperatorStateMetadata, RocksDBStateStoreProvider, StateStoreErrors, TransformWithStateUserFunctionException}
+import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.streaming.{OutputMode, TimeMode}
 import org.apache.spark.sql.types.{BinaryType, StructType}
 import org.apache.spark.util.NextIterator
@@ -51,6 +52,12 @@ abstract class TransformWithStateExecBase(
   with WatermarkSupport
   with TransformWithStateMetadataUtils {
 
+  // Supported state store providers for TransformWithState.
+  // TransformWithState currently supports only RocksDBStateStoreProvider.
+  private val SUPPORTED_STATE_STORE_PROVIDERS = Set(
+    classOf[RocksDBStateStoreProvider].getName
+  )
+
   override def operatorStateMetadataVersion: Int = 2
 
   override def supportsSchemaEvolution: Boolean = true
@@ -216,6 +223,14 @@ abstract class TransformWithStateExecBase(
     }
   }
 
+  /** Validates that the configured state store provider is supported by TransformWithState. */
+  protected def validateStateStoreProvider(): Unit = {
+    val providerName = conf.getConf(SQLConf.STATE_STORE_PROVIDER_CLASS)
+    if (!SUPPORTED_STATE_STORE_PROVIDERS.contains(providerName)) {
+      throw StateStoreErrors.storeBackendNotSupportedForTWS(providerName)
+    }
+  }
+
   /**
    * Executes a block of code with standardized error handling for StatefulProcessor operations.
    * Rethrows SparkThrowables directly and wraps other exceptions in

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/StateStoreErrors.scala

@@ -65,6 +65,11 @@ object StateStoreErrors {
     new StateStoreRemovingColumnFamiliesNotSupportedException(stateStoreProvider)
   }
 
+  def storeBackendNotSupportedForTWS(stateStoreProvider: String):
+    StateStoreBackendNotSupportedForTWSException = {
+    new StateStoreBackendNotSupportedForTWSException(stateStoreProvider)
+  }
+
   def cannotUseColumnFamilyWithInvalidName(operationName: String, colFamilyName: String):
     StateStoreCannotUseColumnFamilyWithInvalidName = {
       new StateStoreCannotUseColumnFamilyWithInvalidName(operationName, colFamilyName)
@@ -313,6 +318,11 @@ class StateStoreRemovingColumnFamiliesNotSupportedException(stateStoreProvider:
     errorClass = "UNSUPPORTED_FEATURE.STATE_STORE_REMOVING_COLUMN_FAMILIES",
     messageParameters = Map("stateStoreProvider" -> stateStoreProvider))
 
+class StateStoreBackendNotSupportedForTWSException(stateStoreProvider: String)
+  extends SparkUnsupportedOperationException(
+    errorClass = "UNSUPPORTED_FEATURE.STORE_BACKEND_NOT_SUPPORTED_FOR_TWS",
+    messageParameters = Map("stateStoreProvider" -> stateStoreProvider))
+
 class StateStoreCannotUseColumnFamilyWithInvalidName(operationName: String, colFamilyName: String)
   extends SparkUnsupportedOperationException(
     errorClass = "STATE_STORE_CANNOT_USE_COLUMN_FAMILY_WITH_INVALID_NAME",

sql/core/src/test/scala/org/apache/spark/sql/streaming/TransformWithStateSuite.scala

@@ -2570,7 +2570,7 @@ class TransformWithStateValidationSuite extends StateStoreMetricsTest {
 
     testStream(result, OutputMode.Update())(
       AddData(inputData, "a"),
-      ExpectFailure[StateStoreMultipleColumnFamiliesNotSupportedException] { t =>
+      ExpectFailure[StateStoreBackendNotSupportedForTWSException] { t =>
         assert(t.getMessage.contains("not supported"))
       }
     )
@@ -2836,7 +2836,7 @@ class TransformWithStateValidationSuite extends StateStoreMetricsTest {
       )
     testStream(result, OutputMode.Update())(
       AddData(inputData, InitInputRow("a", "add", -1.0)),
-      ExpectFailure[StateStoreMultipleColumnFamiliesNotSupportedException] {
+      ExpectFailure[StateStoreBackendNotSupportedForTWSException] {
         (t: Throwable) => {
           assert(t.getMessage.contains("not supported"))
         }