80 lines
2.9 KiB
Python
80 lines
2.9 KiB
Python
#------------------------------------------------------------------------------
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# Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved.
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#------------------------------------------------------------------------------
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#------------------------------------------------------------------------------
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# ConnectionPool.py
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# This script demonstrates the use of connection pooling in cx_Oracle. Pools
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# can significantly reduce connection times for long running applications that
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# repeatedly open and close connections. Internal features help protect against
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# dead connections, and also aid use of Oracle Database features such as FAN
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# and Application Continuity.
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# The script uses threading to show multiple users of the pool. One thread
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# performs a database sleep while another performs a query. A more typical
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# application might be a web service that handles requests from multiple users.
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# Applications that use connections concurrently in multiple threads should set
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# the 'threaded' parameter to True. Note only one operation (such as an execute
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# or fetch) can take place at a time on each connection.
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#
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# Also see SessionCallback.py.
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#
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#------------------------------------------------------------------------------
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import cx_Oracle
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import sample_env
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import threading
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# Create a Connection Pool
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pool = cx_Oracle.SessionPool(user=sample_env.get_main_user(),
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password=sample_env.get_main_password(),
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dsn=sample_env.get_connect_string(), min=2,
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max=5, increment=1, threaded=True)
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# dbms_session.sleep() replaces dbms_lock.sleep() from Oracle Database 18c
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with pool.acquire() as conn:
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sleep_proc_name = "dbms_session.sleep" \
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if int(conn.version.split(".")[0]) >= 18 \
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else "dbms_lock.sleep"
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def TheLongQuery():
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with pool.acquire() as conn:
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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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with pool.acquire() as conn:
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cursor = conn.cursor()
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print("DoALock(): beginning execute...")
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cursor.callproc(sleep_proc_name, (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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