[GitHub] [hudi] xiarixiaoyao commented on a diff in pull request #5737: [HUDI-4178][Stacked on 5733] Addressing performance regressions in Spark DataSourceV2 Integration

[GitBox <gi...@apache.org>]

xiarixiaoyao commented on code in PR #5737:
URL: https://github.com/apache/hudi/pull/5737#discussion_r889519690


##########
hudi-spark-datasource/hudi-spark-common/src/main/scala/org/apache/hudi/HoodieBaseRelation.scala:
##########
@@ -122,29 +122,39 @@ abstract class HoodieBaseRelation(val sqlContext: SQLContext,
     optParams.get(DataSourceReadOptions.TIME_TRAVEL_AS_OF_INSTANT.key)
       .map(HoodieSqlCommonUtils.formatQueryInstant)
 
+  /**
+   * NOTE: Initialization of teh following members is coupled on purpose to minimize amount of I/O
+   *       required to fetch table's Avro and Internal schemas
+   */
   protected lazy val (tableAvroSchema: Schema, internalSchema: InternalSchema) = {
-    val schemaUtil = new TableSchemaResolver(metaClient)
-    val avroSchema = Try(schemaUtil.getTableAvroSchema) match {
-      case Success(schema) => schema
-      case Failure(e) =>
-        logWarning("Failed to fetch schema from the table", e)
-        // If there is no commit in the table, we can't get the schema
-        // t/h [[TableSchemaResolver]], fallback to the provided [[userSchema]] instead.
-        userSchema match {
-          case Some(s) => convertToAvroSchema(s)
-          case _ => throw new IllegalArgumentException("User-provided schema is required in case the table is empty")
-        }
+    val schemaResolver = new TableSchemaResolver(metaClient)
+    val avroSchema: Schema = schemaSpec.map(convertToAvroSchema).getOrElse {
+      Try(schemaResolver.getTableAvroSchema) match {
+        case Success(schema) => schema
+        case Failure(e) =>
+          logError("Failed to fetch schema from the table", e)
+          throw new HoodieSchemaException("Failed to fetch schema from the table")
+      }
     }
-    // try to find internalSchema
-    val internalSchemaFromMeta = try {
-      schemaUtil.getTableInternalSchemaFromCommitMetadata.orElse(InternalSchema.getEmptyInternalSchema)
-    } catch {
-      case _: Exception => InternalSchema.getEmptyInternalSchema
+
+    val schemaEvolutionEnabled: Boolean = optParams.getOrElse(DataSourceReadOptions.SCHEMA_EVOLUTION_ENABLED.key,

Review Comment:
   we cannot rely on this config,  user maybe forget set this config which can lead a incorrectly result



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