feat: add support for transaction statistics (#849)

* feat: add support for transaction statistics

* Hoist transaction_info into base job class

* Add versionadded directive to new property and class

* Include new class in docs reference

Author: plamut

docs/reference.rst

@@ -68,6 +68,7 @@ Job-Related Types
     job.SourceFormat
     job.WriteDisposition
     job.SchemaUpdateOption
+    job.TransactionInfo
 
 
 Dataset

google/cloud/bigquery/__init__.py

@@ -70,6 +70,7 @@
 from google.cloud.bigquery.job import ScriptOptions
 from google.cloud.bigquery.job import SourceFormat
 from google.cloud.bigquery.job import UnknownJob
+from google.cloud.bigquery.job import TransactionInfo
 from google.cloud.bigquery.job import WriteDisposition
 from google.cloud.bigquery.model import Model
 from google.cloud.bigquery.model import ModelReference
@@ -149,6 +150,7 @@
     "GoogleSheetsOptions",
     "ParquetOptions",
     "ScriptOptions",
+    "TransactionInfo",
     "DEFAULT_RETRY",
     # Enum Constants
     "enums",

google/cloud/bigquery/job/__init__.py

@@ -22,6 +22,7 @@
 from google.cloud.bigquery.job.base import ReservationUsage
 from google.cloud.bigquery.job.base import ScriptStatistics
 from google.cloud.bigquery.job.base import ScriptStackFrame
+from google.cloud.bigquery.job.base import TransactionInfo
 from google.cloud.bigquery.job.base import UnknownJob
 from google.cloud.bigquery.job.copy_ import CopyJob
 from google.cloud.bigquery.job.copy_ import CopyJobConfig
@@ -81,5 +82,6 @@
     "QueryPriority",
     "SchemaUpdateOption",
     "SourceFormat",
+    "TransactionInfo",
     "WriteDisposition",
 ]

google/cloud/bigquery/job/base.py

@@ -19,6 +19,7 @@
 import http
 import threading
 import typing
+from typing import Dict, Optional
 
 from google.api_core import exceptions
 import google.api_core.future.polling
@@ -88,6 +89,22 @@ def _error_result_to_exception(error_result):
 )
 
 
+class TransactionInfo(typing.NamedTuple):
+    """[Alpha] Information of a multi-statement transaction.
+
+    https://cloud.google.com/bigquery/docs/reference/rest/v2/Job#TransactionInfo
+
+    .. versionadded:: 2.24.0
+    """
+
+    transaction_id: str
+    """Output only. ID of the transaction."""
+
+    @classmethod
+    def from_api_repr(cls, transaction_info: Dict[str, str]) -> "TransactionInfo":
+        return cls(transaction_info["transactionId"])
+
+
 class _JobReference(object):
     """A reference to a job.
 
@@ -336,6 +353,18 @@ def reservation_usage(self):
             for usage in usage_stats_raw
         ]
 
+    @property
+    def transaction_info(self) -> Optional[TransactionInfo]:
+        """Information of the multi-statement transaction if this job is part of one.
+
+        .. versionadded:: 2.24.0
+        """
+        info = self._properties.get("statistics", {}).get("transactionInfo")
+        if info is None:
+            return None
+        else:
+            return TransactionInfo.from_api_repr(info)
+
     @property
     def error_result(self):
         """Error information about the job as a whole.

tests/system/test_client.py

@@ -1557,6 +1557,40 @@ def test_dml_statistics(self):
         assert query_job.dml_stats.updated_row_count == 0
         assert query_job.dml_stats.deleted_row_count == 3
 
+    def test_transaction_info(self):
+        table_schema = (
+            bigquery.SchemaField("foo", "STRING"),
+            bigquery.SchemaField("bar", "INTEGER"),
+        )
+
+        dataset_id = _make_dataset_id("bq_system_test")
+        self.temp_dataset(dataset_id)
+        table_id = f"{Config.CLIENT.project}.{dataset_id}.test_dml_statistics"
+
+        # Create the table before loading so that the column order is deterministic.
+        table = helpers.retry_403(Config.CLIENT.create_table)(
+            Table(table_id, schema=table_schema)
+        )
+        self.to_delete.insert(0, table)
+
+        # Insert a few rows and check the stats.
+        sql = f"""
+            BEGIN TRANSACTION;
+              INSERT INTO `{table_id}`
+              VALUES ("one", 1), ("two", 2), ("three", 3), ("four", 4);
+
+              UPDATE `{table_id}`
+              SET bar = bar + 1
+              WHERE bar > 2;
+            COMMIT TRANSACTION;
+        """
+        query_job = Config.CLIENT.query(sql)
+        query_job.result()
+
+        # Transaction ID set by the server should be accessible
+        assert query_job.transaction_info is not None
+        assert query_job.transaction_info.transaction_id != ""
+
     def test_dbapi_w_standard_sql_types(self):
         for sql, expected in helpers.STANDARD_SQL_EXAMPLES:
             Config.CURSOR.execute(sql)

tests/unit/job/helpers.py

@@ -162,6 +162,7 @@ def _verifyInitialReadonlyProperties(self, job):
         self.assertIsNone(job.created)
         self.assertIsNone(job.started)
         self.assertIsNone(job.ended)
+        self.assertIsNone(job.transaction_info)
 
         # derived from resource['status']
         self.assertIsNone(job.error_result)

tests/unit/job/test_base.py

@@ -227,6 +227,20 @@ def test_script_statistics(self):
         self.assertEqual(stack_frame.end_column, 14)
         self.assertEqual(stack_frame.text, "QUERY TEXT")
 
+    def test_transaction_info(self):
+        from google.cloud.bigquery.job.base import TransactionInfo
+
+        client = _make_client(project=self.PROJECT)
+        job = self._make_one(self.JOB_ID, client)
+        assert job.transaction_info is None
+
+        statistics = job._properties["statistics"] = {}
+        assert job.transaction_info is None
+
+        statistics["transactionInfo"] = {"transactionId": "123-abc-xyz"}
+        assert isinstance(job.transaction_info, TransactionInfo)
+        assert job.transaction_info.transaction_id == "123-abc-xyz"
+
     def test_num_child_jobs(self):
         client = _make_client(project=self.PROJECT)
         job = self._make_one(self.JOB_ID, client)

tests/unit/job/test_query.py

@@ -128,6 +128,18 @@ def _verify_dml_stats_resource_properties(self, job, resource):
         else:
             assert job.dml_stats is None
 
+    def _verify_transaction_info_resource_properties(self, job, resource):
+        resource_stats = resource.get("statistics", {})
+
+        if "transactionInfo" in resource_stats:
+            resource_transaction_info = resource_stats["transactionInfo"]
+            job_transaction_info = job.transaction_info
+            assert job_transaction_info.transaction_id == resource_transaction_info.get(
+                "transactionId"
+            )
+        else:
+            assert job.transaction_info is None
+
     def _verify_configuration_properties(self, job, configuration):
         if "dryRun" in configuration:
             self.assertEqual(job.dry_run, configuration["dryRun"])
@@ -137,6 +149,7 @@ def _verify_configuration_properties(self, job, configuration):
     def _verifyResourceProperties(self, job, resource):
         self._verifyReadonlyResourceProperties(job, resource)
         self._verify_dml_stats_resource_properties(job, resource)
+        self._verify_transaction_info_resource_properties(job, resource)
 
         configuration = resource.get("configuration", {})
         self._verify_configuration_properties(job, configuration)
@@ -325,6 +338,22 @@ def test_from_api_repr_with_dml_stats(self):
         self.assertIs(job._client, client)
         self._verifyResourceProperties(job, RESOURCE)
 
+    def test_from_api_repr_with_transaction_info(self):
+        self._setUpConstants()
+        client = _make_client(project=self.PROJECT)
+        RESOURCE = {
+            "id": self.JOB_ID,
+            "jobReference": {"projectId": self.PROJECT, "jobId": self.JOB_ID},
+            "configuration": {"query": {"query": self.QUERY}},
+            "statistics": {"transactionInfo": {"transactionId": "1a2b-3c4d"}},
+        }
+        klass = self._get_target_class()
+
+        job = klass.from_api_repr(RESOURCE, client=client)
+
+        self.assertIs(job._client, client)
+        self._verifyResourceProperties(job, RESOURCE)
+
     def test_from_api_repr_w_properties(self):
         from google.cloud.bigquery.job import CreateDisposition
         from google.cloud.bigquery.job import SchemaUpdateOption