HeartSaVioR commented on a change in pull request #24173: [SPARK-27237][SS]
Introduce State schema validation among query restart
URL: https://github.com/apache/spark/pull/24173#discussion_r267988746
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/StateStore.scala
##########
@@ -477,5 +487,73 @@ object StateStore extends Logging {
None
}
}
-}
+ private class StateSchemaCompatibilityChecker(
+ providerId: StateStoreProviderId,
+ hadoopConf: Configuration) {
+
+ private val storeCpLocation = providerId.storeId.storeCheckpointLocation()
+ private val fm = CheckpointFileManager.create(storeCpLocation, hadoopConf)
+ private val schemaFileLocation = schemaFile(storeCpLocation)
+
+ fm.mkdirs(schemaFileLocation.getParent)
+
+ def check(keySchema: StructType, valueSchema: StructType): Unit = {
+ if (fm.exists(schemaFileLocation)) {
+ logDebug(s"Schema file for provider $providerId exists. Comparing with
provided schema.")
+ val (storedKeySchema, storedValueSchema) = readSchemaFile()
+
+ def typesEq(schema1: StructType, schema2: StructType): Boolean = {
+ val fieldToType: StructField => (DataType, Boolean) = f =>
(f.dataType, f.nullable)
+ (schema1.length == schema2.length) &&
+ schema1.map(fieldToType).equals(schema2.map(fieldToType))
+ }
+
+ val errorMsg = "Provided schema doesn't match to the schema for
existing state! " +
+ "Please note that Spark allow difference of field name: check count
of fields " +
+ "and data type of each field.\n" +
+ s"- provided schema: key $keySchema value $valueSchema\n" +
+ s"- existing schema: key $storedKeySchema value $storedValueSchema\n"
+
+ if (!typesEq(keySchema, storedKeySchema) || !typesEq(valueSchema,
storedValueSchema)) {
+ logError(errorMsg)
+ throw new IllegalStateException(errorMsg)
+ }
+ } else {
Review comment:
Now these things are done. One possible but up to preference todo is warn
users if field name change is detected, which might be possible to break query.
Why it's up to preference is end users can intentionally change the name.
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