Steps to reproduce
1. Setup server with short WAIT_TIMEOUT:
docker run -e MARIADB_ROOT_PASSWORD="<put_password_here>" -p 3306:3306 mariadb:10.6.11 --wait-timeout=10
2. Create a connection pool (see attached file)
3. Wait a little longer than WAIT_TIMEOUT
4. Get pool_size connections without closing them
Expected outcome
Each connection returned by get_connection is unique.
Actual outcome
One connection is returned twice
Suspected cause
get_connections deletes the connection to be returned from _connections_free and adds it to _connections_used
for i in range(0, len(self._connections_free)):
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conn = self._connections_free[i]
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# abbreviated: call _replace_connection if necessary;
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conn._used += 1
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self._connections_used.append(conn)
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del self._connections_free[i]
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If _replace_connection is called, it adds the new connection at the end of the list, so
del self._connections_free[i]
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deletes a different connection.
Possible fix
See attached patch.
diff --git a/mariadb/connectionpool.py b/mariadb/connectionpool.py
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index 882ff69..b17c984 100644
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--- a/mariadb/connectionpool.py
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+++ b/mariadb/connectionpool.py
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@@ -218,7 +218,8 @@ class ConnectionPool(object):
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conn._used += 1
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self._connections_used.append(conn)
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- del self._connections_free[i]
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+ x = self._connections_free.index(conn)
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+ del self._connections_free[x]
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return conn
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return None
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duplicate_connection.patch
test_duplicate_connection.py