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Re: [IndexedDB] Need a method to remove a database

From: Jonas Sicking <jonas@sicking.cc>
Date: Thu, 5 Aug 2010 10:22:25 -0700
Message-ID: <AANLkTikCGZc0w1vM=j8QqET-1D9XtxdjejnrUv7rFHvJ@mail.gmail.com>
To: Jeremy Orlow <jorlow@chromium.org>
Cc: Shawn Wilsher <sdwilsh@mozilla.com>, public-webapps WG <public-webapps@w3.org>
On Thu, Aug 5, 2010 at 2:30 AM, Jeremy Orlow <jorlow@chromium.org> wrote:
> On Wed, Aug 4, 2010 at 7:15 PM, Jonas Sicking <jonas@sicking.cc> wrote:
>>
>> On Wed, Aug 4, 2010 at 2:56 AM, Jeremy Orlow <jorlow@chromium.org> wrote:
>> > On Tue, Aug 3, 2010 at 11:26 PM, Jonas Sicking <jonas@sicking.cc> wrote:
>> >>
>> >> On Tue, Aug 3, 2010 at 3:20 PM, Shawn Wilsher <sdwilsh@mozilla.com>
>> >> wrote:
>> >> > Hey all,
>> >> >
>> >> > Some of the feedback I've been seeing on the web is that there is no
>> >> > way
>> >> > to
>> >> > remove a database.  Examples seem to be "web page wants to allow the
>> >> > user to
>> >> > remove the data they stored".  A site can almost accomplish this now
>> >> > by
>> >> > removing all object stores, but we still end up storing some meta
>> >> > data
>> >> > (version number).  Does this seem like a legit request to everyone?
>> >>
>> >> Sounds legit to me. Feel somewhat embarrassed that I've missed this so
>> >> far
>> >> :)
>> >
>> > Agreed.
>> > What should the semantics be for open database connections?  We could do
>> > something like setVersion, but I'd just as soon nuke any existing
>> > connection
>> > (i.e. make all future operations fail).  This seems reasonable since the
>> > reasons we didn't do this for setVersion (data loss) don't really seem
>> > to
>> > apply here.
>>
>> Actually, there could dataloss apply here. Consider a page which
>> creates a temporary database, fills it with data, and then slowly
>> sends it to the server. Once all data has been sent to the server the
>> database is removed.
>>
>> If you have two instances of that page open, one could remove the
>> database while the other is still writing to it.
>>
>> Though this seems like a pretty scary setup anyway since if the user
>> closes the second page midway through, the first one will succeed in
>> deleting the database no matter what.
>
> Well, presumably the site won't delete a database programmatically if it
> still has important information in it.  I mean, the same scenario you just
> explained could happen with .clear() or .removeObjectStore() as well.

It can with .clear(), but it can't with .removeObjectStore() since you
can only call that when you have a VERSION_CHANGE transaction, which
you can only get once no other connections to the database exist.

/ Jonas
Received on Thursday, 5 August 2010 17:23:20 GMT

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