Dry runs return bytes processed, and cache hit now

Author: egeucak

bigquery/client.py

@@ -243,7 +243,7 @@ def _submit_query_job(self, query_data):
  -------
  tuple
  job id and query results if query completed. If dry_run is True,
- job id will be None and results will be empty if the query is valid
+ job id will be None and results will be [cacheHit and totalBytesProcessed] if the query is valid
  or a dict containing the response if invalid.
 
  Raises
@@ -269,13 +269,17 @@ def _submit_query_job(self, query_data):
  schema = query_reply.get('schema', {'fields': None})['fields']
  rows = query_reply.get('rows', [])
  job_complete = query_reply.get('jobComplete', False)
+ cache_hit = query_reply['cacheHit']
+ total_bytes_processed = query_reply['totalBytesProcessed']
 
  # raise exceptions if it's not an async query
  # and job is not completed after timeout
  if not job_complete and query_data.get("timeoutMs", False):
  logger.error('BigQuery job %s timeout' % job_id)
  raise BigQueryTimeoutException()
-
+ 
+ if query_data.get("dryRun", True):
+ return job_id, [cache_hit, total_bytes_processed]
  return job_id, [self._transform_row(row, schema) for row in rows]
 
  def _get_job_reference(self, job_id):
@@ -345,8 +349,8 @@ def query(self, query, max_results=None, timeout=0, dry_run=False, use_legacy_sq
  How long to wait for the query to complete, in seconds before
  the request times out and returns.
  dry_run : bool, optional
- If True, the query isn't actually run. A valid query will return an
- empty response, while an invalid one will return the same error
+ If True, the query isn't actually run. A valid query will return 
+ cache hit, and total bytes processed, while an invalid one will return the same error
  message it would if it wasn't a dry run.
  use_legacy_sql : bool, optional. Default True.
  If False, the query will use BigQuery's standard SQL (https://cloud.google.com/bigquery/sql-reference/)
@@ -359,7 +363,7 @@ def query(self, query, max_results=None, timeout=0, dry_run=False, use_legacy_sq
  -------
  tuple
  (job id, query results) if the query completed. If dry_run is True,
- job id will be None and results will be empty if the query is valid
+ job id will be None and results will be [cacheHit and totalBytesProcessed] if the query is valid
  or a ``dict`` containing the response if invalid.
 
  Raises