Use Float instead of BigInteger in SQLAlchemyJobStore to maintain proper job order in cases where next run times differ by less than a second (fixes #63)

2 files changed, 11 insertions, 3 deletions

diff --git a/apscheduler/jobstores/sqlalchemy.py b/apscheduler/jobstores/sqlalchemy.py
index 2a13ad5..4e0c0e2 100644
--- a/apscheduler/jobstores/sqlalchemy.py
+++ b/apscheduler/jobstores/sqlalchemy.py
@@ -10,7 +10,7 @@ except ImportError:  # pragma: nocover
     import pickle
 
 try:
-    from sqlalchemy import create_engine, Table, Column, MetaData, Unicode, BigInteger, LargeBinary, select
+    from sqlalchemy import create_engine, Table, Column, MetaData, Unicode, Float, LargeBinary, select
     from sqlalchemy.exc import IntegrityError
 except ImportError:  # pragma: nocover
     raise ImportError('SQLAlchemyJobStore requires SQLAlchemy installed')
@@ -44,11 +44,11 @@ class SQLAlchemyJobStore(BaseJobStore):
         else:
             raise ValueError('Need either "engine" or "url" defined')
 
-        # 767 = max key length in MySQL for InnoDB tables
+        # 767 = max key length in MySQL for InnoDB tables, 25 = precision that translates to an 8-byte float
         self.jobs_t = Table(
             tablename, metadata,
             Column('id', Unicode(767, _warn_on_bytestring=False), primary_key=True),
-            Column('next_run_time', BigInteger, index=True),
+            Column('next_run_time', Float(25), index=True),
             Column('job_state', LargeBinary, nullable=False)
         )
 
diff --git a/tests/test_jobstores.py b/tests/test_jobstores.py
index 191d4fd..58e8533 100644
--- a/tests/test_jobstores.py
+++ b/tests/test_jobstores.py
@@ -114,6 +114,14 @@ def test_get_pending_jobs(jobstore, create_add_job, timezone):
     assert jobs == []
 
 
+def test_get_pending_jobs_subsecond_difference(jobstore, create_add_job, timezone):
+    job1 = create_add_job(jobstore, dummy_job, datetime(2014, 7, 7, 0, 0, 0, 401))
+    job2 = create_add_job(jobstore, dummy_job2, datetime(2014, 7, 7, 0, 0, 0, 402))
+    job3 = create_add_job(jobstore, dummy_job3, datetime(2014, 7, 7, 0, 0, 0, 400))
+    jobs = jobstore.get_due_jobs(timezone.localize(datetime(2014, 7, 7, 1)))
+    assert jobs == [job3, job1, job2]
+
+
 def test_get_next_run_time(jobstore, create_add_job, timezone):
     create_add_job(jobstore, dummy_job, datetime(2016, 5, 3))
     create_add_job(jobstore, dummy_job2, datetime(2014, 2, 26))