a) How extensive is the visitor and customer url log actually is? It logs every page view for customers and/or visitors?
Yes. Visitory/Url loging is happening per each page request. This is managing by Mage_Log
module. If you look into this module, you can find following configuration in config.xml
file.
<frontend>
<events>
<controller_action_predispatch>
<observers>
<log>
<class>log/visitor</class>
<method>initByRequest</method>
</log>
</observers>
</controller_action_predispatch>
<controller_action_postdispatch>
<observers>
<log>
<class>log/visitor</class>
<method>saveByRequest</method>
</log>
</observers>
</controller_action_postdispatch>
<customer_login>
<observers>
<log>
<class>log/visitor</class>
<method>bindCustomerLogin</method>
</log>
</observers>
</customer_login>
<customer_logout>
<observers>
<log>
<class>log/visitor</class>
<method>bindCustomerLogout</method>
</log>
</observers>
</customer_logout>
<sales_quote_save_after>
<observers>
<log>
<class>log/visitor</class>
<method>bindQuoteCreate</method>
</log>
</observers>
</sales_quote_save_after>
<checkout_quote_destroy>
<observers>
<log>
<class>log/visitor</class>
<method>bindQuoteDestroy</method>
</log>
</observers>
</checkout_quote_destroy>
</events>
</frontend>
Here both controller_action_predispatch
and controller_action_postdispatch
will be fired in each URL request and correspondingly a log entry will be created/updated.
b) On visitor_log_url table is a session_id column. Where is set the Lifetime? How is it renewed? How can i call it in order to add it to newsletter_subscriber or to add it on log_quote?
Be honest, this question is not clear for me. Basically session id is generated by Mage_Core_Model_Session
instance whose life time is purely depends on your system configuration.
c) Or maybe someone could recommend an extension that does something like this?
Sorry, I don't know any extension which extends Magento's default Mage_Log
module.