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Re: [IndexedDB] What happens when the version changes?

From: Jonas Sicking <jonas@sicking.cc>
Date: Tue, 18 May 2010 15:31:40 -0700
Message-ID: <AANLkTilnWQc3Ezbd6sQSVfhuzUNLuCGlCwJ0kFpTOMBz@mail.gmail.com>
To: Nikunj Mehta <nikunj@o-micron.com>
Cc: Jeremy Orlow <jorlow@chromium.org>, Shawn Wilsher <sdwilsh@mozilla.com>, public-webapps WG <public-webapps@w3.org>
On Tue, May 18, 2010 at 2:57 PM, Nikunj Mehta <nikunj@o-micron.com> wrote:
>
> On May 18, 2010, at 2:33 PM, Jeremy Orlow wrote:
>
> On Tue, May 18, 2010 at 9:36 PM, Shawn Wilsher <sdwilsh@mozilla.com> wrote:
>>
>> On 5/18/2010 1:02 PM, Nikunj Mehta wrote:
>>>
>>> A database connection that locks the entire database cannot be opened if
>>> there is another database connection that locks at least one database
>>> object, e.g., an index or object store.
>>
>> So basically, as long as some connection holds a database lock, you won't
>> be able to do any upgrade.
>
> Sure, but this is true of Jonas' proposal as well.
>
> But to me it is a no-op. The spec already does what Jonas is proposing -
> lock out users when an upgrade is in progress and wait to start an upgrade
> if a user is using the application.

Note that in our proposal, having a database open does not hold any
locks. It simply holds metadata (such as objectStore and index names)
in memory. It is totally ok for the application to open the database
when the user initially loads the page, and never close it until the
user leaves the page.

In fact, I would encourage users to do this since it allows for
reading data using a single level asynchronous callbacks, and so makes
for very readable code.

Because our proposal is incompatible with the versioning mechanism
that the spec uses, I would propose that we first decide on if
mozillas proposal should be accepted before we decide on what
versioning mechanism we should use.

/ Jonas
Received on Tuesday, 18 May 2010 22:58:26 GMT

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