[GitHub] [incubator-gobblin] ZihanLi58 commented on a change in pull request #3091: [GOBBLIN-1248] Fix discrepancy between table schema and file schema

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

ZihanLi58 commented on a change in pull request #3091:
URL: https://github.com/apache/incubator-gobblin/pull/3091#discussion_r476744238



##########
File path: gobblin-hive-registration/src/main/java/org/apache/gobblin/hive/metastore/HiveMetaStoreBasedRegister.java
##########
@@ -192,16 +193,30 @@ protected void registerPath(HiveSpec spec) throws IOException {
       throw new IOException(e);
     }
   }
-  //TODO: We need to find a better to get the latest schema
-  private void updateSchema(HiveSpec spec, Table table) throws IOException{
+  private void updateSchema(HiveSpec spec, Table table, HiveTable existingTable) throws IOException{
 
     if (this.schemaRegistry.isPresent()) {
       try (Timer.Context context = this.metricContext.timer(GET_AND_SET_LATEST_SCHEMA).time()) {
-        String latestSchema = this.schemaRegistry.get().getLatestSchema(topicName).toString();
-        spec.getTable().getSerDeProps().setProp(AvroSerdeUtils.AvroTableProperties.SCHEMA_LITERAL.getPropName(), latestSchema);
+        Schema latestSchema = (Schema) this.schemaRegistry.get().getLatestSchemaByTopic(topicName);

Review comment:
       According to kafka team, schema registry allows "out of order registration" of schemas - think of this as sorting schemas by compatibility instead of by timestamp. this means chronological latest is NOT what the registry considers latest.  I also include this information in comments to avoid confusing
   In addition, I update the PR to first compare the creation time with existing schema, if we see difference, we will then fetch latest schema to get the latest schema creation time. In this way, we can avoid too many calls to schema registry




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org