Snippet showing how to disable Magneto's Database Logging Events

local.xml

<config>
    ...
    <global>
        ...
        <frontend>
            <events>
                <controller_action_predispatch>
                    <observers><log><type>disabled</type></log></observers>
                </controller_action_predispatch>
                <controller_action_postdispatch>
                    <observers><log><type>disabled</type></log></observers>
                </controller_action_postdispatch>
                <customer_login>
                    <observers><log><type>disabled</type></log></observers>
                </customer_login>
                <customer_logout>
                    <observers><log><type>disabled</type></log></observers>
                </customer_logout>
                <sales_quote_save_after>
                    <observers><log><type>disabled</type></log></observers>
                </sales_quote_save_after>
                <checkout_quote_destroy>
                    <observers><log><type>disabled</type></log></observers>
                </checkout_quote_destroy>
            </events>
        </frontend>
    </global>
</config>