Add sample demonstrating the use of threads and concurrent execution of

database operations.
This commit is contained in:
Anthony Tuininga 2017-03-20 13:20:01 -06:00
parent 550d326c68
commit 37e449d62c
1 changed files with 65 additions and 0 deletions

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samples/Threads.py Normal file
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#------------------------------------------------------------------------------
# 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!")