mirror of
https://github.com/psycopg/psycopg2.git
synced 2024-09-21 11:18:49 +03:00
62 lines
1.9 KiB
Python
62 lines
1.9 KiB
Python
import psycopg2, psycopg2.extensions
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import threading
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import gc
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import time
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import sys
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# inherit psycopg2 connection class just so that
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# garbage collector enters the tp_clear code path
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# in delete_garbage()
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class my_connection(psycopg2.extensions.connection):
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pass
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class db_user(threading.Thread):
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def run(self):
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conn2 = psycopg2.connect(sys.argv[1], connection_factory=my_connection)
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cursor = conn2.cursor()
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cursor.execute("UPDATE test_psycopg2_dealloc SET a = 3", async=1)
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# the conn2 desctructor will block indefinitely
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# on the completion of the query
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# (and it will not be holding the GIL during that time)
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print >> sys.stderr, "begin conn2 del"
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del cursor, conn2
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print >> sys.stderr, "end conn2 del"
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def main():
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# lock out a db row
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conn1 = psycopg2.connect(sys.argv[1], connection_factory=my_connection)
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cursor = conn1.cursor()
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cursor.execute("DROP TABLE IF EXISTS test_psycopg2_dealloc")
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cursor.execute("CREATE TABLE test_psycopg2_dealloc (a int)")
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cursor.execute("INSERT INTO test_psycopg2_dealloc VALUES (1)")
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conn1.commit()
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cursor.execute("UPDATE test_psycopg2_dealloc SET a = 2", async=1)
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# concurrent thread trying to access the locked row
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db_user().start()
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# eventually, a gc.collect run will happen
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# while the conn2 is inside conn_close()
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# but this second dealloc won't get blocked
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# as it will avoid conn_close()
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for i in range(10):
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if gc.collect():
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print >> sys.stderr, "garbage collection done"
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break
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time.sleep(1)
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# we now unlock the row by invoking
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# the desctructor of conn1. This will permit the
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# concurrent thread destructor of conn2 to
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# continue and it will end up trying to free
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# self->dsn a second time.
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print >> sys.stderr, "begin conn1 del"
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del cursor, conn1
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print >> sys.stderr, "end conn1 del"
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if __name__ == '__main__':
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main()
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