Adding dispatch of an event before and after applyAllUpdates()

[brobie]

This allows for the ability to put in a mechanism to prevent errors from
being displayed to users if more than one make a request in the same
span of time that the install/upgrade scripts are running.

This mechanism could be: waiting, sending to an separate page, etc.

Now, we would not have to turn on maintenance mode...potentially.

[magento-team]

Hi @brobie and @colinmollenhour,

we're going to implement independent install/upgrade application in approximately 4th Quarter of 2012, before Magento 2 stable release. This application should resolve any issues with installing/upgrading Magento, including described in this thread.

While it's not implemented yet, you can use @colinmollenhour's script where it's possible. But generally we don't recommend upgrading on production system.

Looks like @brobie's proposal should be considered carefully. The point is that it's impossible now to determine on dispatching 'apply_db_schema_updates_before' event if any upgrade will be executed. As a result a method which observes this event will be executed every time the page is loading, regardless of upgrade process will be run or not. It can produce redirecting (or any other action provided by the observer) for some visitors even if no upgrade is running.

Closing the request and thank you for the proposal.