[server] use a LifoQueue in _CnxSetPool
In postgresql, some cache is attached to the connection. Using a LifoQueue
(last-in, first-out) makes a few connections to get the most load which give
best performance.
Latest changes
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* table of `all latest changes`_
Links below is providing useful RQL query example.
.. _all latest changes: ../view?rql=Any+M%2CX+WHERE+X+modification_date+M+ORDERBY+M+DESC+LIMIT+30