fix: pass object_encoding from schema when dumping bigquery to parquet

apps/api/src/python/query/bigquery.ts

@@ -94,11 +94,47 @@ def _briefer_make_bq_query():
                     print(json.dumps({"type": "log", "message": f"Converting column {col} to list"}))
                     df[col] = df[col].apply(lambda x: json.loads(json.dumps(x if x is not None else [], default=str)))
 
+    def object_encoding_from_schema(schema):
+        object_encoding = {}
+        for field in schema:
+            if field.field_type == 'STRING':
+                object_encoding[field.name] = 'utf8'
+            elif field.field_type == 'BYTES':
+                object_encoding[field.name] = 'bytes'
+            elif field.field_type == 'INTEGER':
+                object_encoding[field.name] = 'int'
+            elif field.field_type == 'INT64':
+                object_encoding[field.name] = 'int'
+            elif field.field_type == 'FLOAT64':
+                object_encoding[field.name] = 'float'
+            elif field.field_type == 'NUMERIC':
+                object_encoding[field.name] = 'decimal'
+            elif field.field_type == 'BOOL':
+                object_encoding[field.name] = 'bool'
+            elif field.field_type == 'TIMESTAMP':
+                object_encoding[field.name] = 'datetime'
+            elif field.field_type == 'DATE':
+                object_encoding[field.name] = 'date'
+            elif field.field_type == 'TIME':
+                object_encoding[field.name] = 'time'
+            elif field.field_type == 'DATETIME':
+                object_encoding[field.name] = 'datetime'
+            elif field.field_type == 'RECORD':
+                object_encoding[field.name] = 'json'
+            elif field.field_type == 'ARRAY':
+                object_encoding[field.name] = 'json'
+            elif field.field_type == 'STRUCT':
+                object_encoding[field.name] = 'json'
+            else:
+                object_encoding[field.name] = 'json'
+        return object_encoding
+
     aborted = False
     dump_file_base = f'/home/jupyteruser/.briefer/query-${queryId}'
     parquet_file_path = f'{dump_file_base}.parquet.gzip'
     csv_file_path = f'{dump_file_base}.csv'
 
+    object_encoding = None
     queue = queue.Queue()
     def dump_worker():
         dumped_count = 0
@@ -128,13 +164,13 @@ def _briefer_make_bq_query():
 
             mode = 'a'
             if is_first:
-              mode = 'w'
-              os.makedirs('/home/jupyteruser/.briefer', exist_ok=True)
+                mode = 'w'
+                os.makedirs('/home/jupyteruser/.briefer', exist_ok=True)
 
             try:
                 # write to parquet
                 print(json.dumps({"type": "log", "message": f"Dumping {len(chunk)} rows as parquet, queue size {queue.qsize()}"}))
-                chunk.to_parquet(parquet_file_path, compression='gzip', index=False, append=not is_first, engine="fastparquet")
+                chunk.to_parquet(parquet_file_path, compression='gzip', index=False, append=not is_first, engine="fastparquet", object_encoding=object_encoding)
 
                 # write to csv
                 print(json.dumps({"type": "log", "message": f"Dumping {len(chunk)} rows as csv, queue size {queue.qsize()}"}))
@@ -187,6 +223,7 @@ def _briefer_make_bq_query():
 
         print(json.dumps({"type": "log", "message": "Fetching resulting schema"}))
         schema = get_query_schema(${JSON.stringify(query)}, client)
+        object_encoding = object_encoding_from_schema(schema)
 
         columns_by_type = {}
         for field in schema: