[mythtv] [mythtv-commits] Ticket #4013: Prompt before upgrading database schema

Nigel Pearson nigel at ind.tansu.com.au
Thu Sep 27 03:59:52 UTC 2007

On 27/09/2007, at 3:49 AM, Isaac Richards wrote:

>> most things are still safe because they
>> cannot actually talk to the backend.
> That doesn't check the DB version, does it?

True, but it negates most of the risk for backends
that are old enough to have a lesser protocol.

Of course, there is still a large risk window
if DB version has changed lots since the last
backend protocol change.

I started a statictical analysis of this:
but didn't get very far.

>> If you are still uncomfortable, maybe a second
>> OkPopup after the user selects "Use old..." ?
> How about a command line option to connect,
> instead?  --really-connect-to-old-db-version-i-know-it-might-break- 
> everything

Heh. I thought IGNORE_PROTO_VER_MISMATCH was a long symbol!

>> Possible, although the current ability to upgrade
>> from several programs is a lot simpler?
> I suppose, but maybe check that, if run from the frontend,
> no backends (or at least the master) are currently running?


I guess if mythtv-setup or mythbackend are prompting
the the upgrade, having mythfrontends using the DB
is equally risky.

(Nigel's brain suddenly explodes
  from the combinatorial overload)

Now I realise why we hadn't done this before :-(

>   And maybe a second level
> confirmation that the upgrade will happen?

Will do. That will also give me more room
so I can improve the warning message(s).

And I will make the "Use old schema" optional
(depending on a magic value in DBSchemaAutoUpgrade)

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