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