84cd718977
connection.ltxid and error.isrecoverable as well as a sample that indicates how it could be used.
63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
#------------------------------------------------------------------------------
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# TransactionGuard.py
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# This script demonstrates the use of Transaction Guard to verify if a
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# transaction has completed, ensuring that a duplicate transaction is not
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# created or attempted if the application chooses to handle the error. This
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# feature is only available in Oracle Database 12.1. It follows loosely the
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# OCI sample provided by Oracle in its documentation about OCI and Transaction
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# Guard.
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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 sys
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# constants
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SESSION_MIN = 1
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SESSION_MAX = 9
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SESSION_INCR = 2
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USER_NAME = "cx_Oracle"
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PASSWORD = "dev"
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DATABASE = "t12-tg"
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# for Python 2.7 we need raw_input
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try:
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input = raw_input
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except NameError:
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pass
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# create transaction and generate a recoverable error
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pool = cx_Oracle.SessionPool(USER_NAME, PASSWORD, DATABASE, SESSION_MIN,
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SESSION_MAX, SESSION_INCR)
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connection = pool.acquire()
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cursor = connection.cursor()
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cursor.execute("""
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delete from TestExecuteMany
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where IntCol = 1""")
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cursor.execute("""
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insert into TestExecuteMany
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values (1, null)""")
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connection.commit()
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input("Please kill %s session now. Press ENTER when complete." % USER_NAME)
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try:
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connection.commit() # this should fail
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sys.exit("Session was not killed. Terminating.")
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except cx_Oracle.DatabaseError as e:
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errorObj, = e.args
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if not errorObj.isrecoverable:
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sys.exit("Session is not recoverable. Terminating.")
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ltxid = connection.ltxid
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if not ltxid:
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sys.exit("Logical transaction not available. Terminating.")
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pool.drop(connection)
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# check if previous transaction completed
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connection = pool.acquire()
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cursor = connection.cursor()
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_, committed, completed = cursor.callproc("dbms_app_cont.get_ltxid_outcome",
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(cx_Oracle.Binary(ltxid), cursor.var(bool), cursor.var(bool)))
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print("Failed transaction was committed:", committed)
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print("Failed call was completed:", completed)
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