nsivabalan commented on code in PR #5737:
URL: https://github.com/apache/hudi/pull/5737#discussion_r889523138
##########
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:
@xiarixiaoyao : A tangential question trying to understand something. can
you help me understand the interplay here or how the config is used. for the
first time on read path, if someone enables this config, internal schema will
be generated.
OptionA:
After that, all read and write paths will rely on presence of InternalSchema
is it? Even on the read path, we just check for presence of internal schema.
OptionB:
or is it that write path will always rely on the schema evolution enabled
config and read path will rely on the presence of internal schema?
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