indexer: epoch commit debugging (MystenLabs#10565)

## Description 

I saw error msg of 
```
INFO sui_indexer::handlers::checkpoint_handler: Epoch 750 committed.
....
2023-04-07T22:54:49.669481Z  WARN sui_indexer::handlers::checkpoint_handler: Indexer epoch commit failed with error: PostgresWriteError("empty range bound specified for partition \"objects_history_partition_749\""), retrying after 100 milli-secs...
```

I do not have a theory, this seems unlikely at the first glance, added
some loggings there then.

## Test Plan 

eyeball

crates/sui-indexer/src/handlers/checkpoint_handler.rs

@@ -301,7 +301,7 @@ where
                     }
                     epoch_db_guard.stop_and_record();
                     self.metrics.total_epoch_committed.inc();
-                    info!("Epoch {} committed.", indexed_epoch.new_epoch.epoch,);
+                    info!("Epoch {} committed.", indexed_epoch.new_epoch.epoch);
                 }
             } else {
                 // sleep for 1 sec to avoid occupying the mutex, as this happens once per epoch / day

crates/sui-indexer/src/store/pg_indexer_store.rs

@@ -1524,7 +1524,9 @@ impl PartitionManager {
                         "ALTER TABLE {table} DETACH PARTITION {table}_partition_{last_epoch_id};"
                     );
                     let attach_partition_with_new_range = format!("ALTER TABLE {table} ATTACH PARTITION {table}_partition_{last_epoch_id} FOR VALUES FROM ('{last_epoch_start_cp}') TO ('{next_epoch_start_cp}');");
+                    info! {"Changed last epoch partition {last_epoch_id} for {table}, with new range {last_epoch_start_cp} to {next_epoch_start_cp}"};
                     let new_partition = format!("CREATE TABLE {table}_partition_{next_epoch_id} PARTITION OF {table} FOR VALUES FROM ({next_epoch_start_cp}) TO (MAXVALUE);");
+                    info! {"Created epoch partition {next_epoch_id} for {table}, with new range {next_epoch_start_cp} to MAXVALUE"};
                     diesel::RunQueryDsl::execute(diesel::sql_query(detach_partition), conn)?;
                     diesel::RunQueryDsl::execute(
                         diesel::sql_query(attach_partition_with_new_range),