Add sample demonstrating the use of threads and concurrent execution of

database operations.

Author: anthony-tuininga

python/Threads.py

@@ -0,0 +1,65 @@
+#------------------------------------------------------------------------------
+# Copyright 2017, Oracle and/or its affiliates. All rights reserved.
+#------------------------------------------------------------------------------
+
+#------------------------------------------------------------------------------
+# Threads.py
+# This script demonstrates the use of threads with cx_Oracle. A session pool
+# is used so that multiple connections are available to perform work on the
+# database. Only one operation (such as an execute or fetch) can take place at
+# a time on a connection. In the below example, one of the threads performs
+# dbms_lock.sleep while the other performs a query.
+#
+# This script requires cx_Oracle 2.5 and higher.
+#------------------------------------------------------------------------------
+
+from __future__ import print_function
+
+import cx_Oracle
+import threading
+
+pool = cx_Oracle.SessionPool("cx_Oracle", "dev", "localhost/orcl", 2, 5, 1,
+ threaded = True)
+
+def TheLongQuery():
+ conn = pool.acquire()
+ cursor = conn.cursor()
+ cursor.arraysize = 25000
+ print("TheLongQuery(): beginning execute...")
+ cursor.execute("""
+ select *
+ from
+ TestNumbers
+ cross join TestNumbers
+ cross join TestNumbers
+ cross join TestNumbers
+ cross join TestNumbers
+ cross join TestNumbers""")
+ print("TheLongQuery(): done execute...")
+ while True:
+ rows = cursor.fetchmany()
+ if not rows:
+ break
+ print("TheLongQuery(): fetched", len(rows), "rows...")
+ print("TheLongQuery(): all done!")
+
+
+def DoALock():
+ conn = pool.acquire()
+ cursor = conn.cursor()
+ print("DoALock(): beginning execute...")
+ cursor.callproc("dbms_lock.sleep", (5,))
+ print("DoALock(): done execute...")
+
+
+thread1 = threading.Thread(None, TheLongQuery)
+thread1.start()
+
+thread2 = threading.Thread(None, DoALock)
+thread2.start()
+
+thread1.join()
+thread2.join()
+
+print("All done!")
+