W3C home > Mailing lists > Public > public-webapps@w3.org > January to March 2010

Re: [WebSQLDatabase] Adding a vacuum() call

From: Dirk Pranke <dpranke@chromium.org>
Date: Fri, 12 Mar 2010 13:31:15 -0800
Message-ID: <3726d1bf1003121331g7b3abf98y61a32f6f0fa89237@mail.gmail.com>
To: Jeremy Orlow <jorlow@google.com>
Cc: Dumitru Daniliuc <dumi@google.com>, João Eiras <joaoe@opera.com>, public-webapps <public-webapps@w3.org>
I admit to not being super familiar with the spec as it currently
stands, but I find the idea
that we would add something like this fairly unappealing. I'm not
familiar with any other
database API that asks the application programmer to some sort of GC
as part of the
application. I almost feel like if you're going to add this, you
should drop any pretense of
calling this a generic SQL interface, and just call it the "WebSQLLite spec".

-- Dirk

2010/3/9 Jeremy Orlow <jorlow@google.com>:
> On Mon, Mar 8, 2010 at 8:47 PM, Dumitru Daniliuc <dumi@google.com> wrote:
>>
>>
>> On Mon, Mar 8, 2010 at 3:39 AM, João Eiras <joaoe@opera.com> wrote:
>>>
>>>>> I don't see how the callbacks are useful though. Vacuum works
>>>>> transparently, its effects are not visible, and what should the page do
>>>>> in
>>>>> case of error ?
>>>>>
>>>>
>>>> i was thinking of something like:
>>>>
>>>> db.defragment(errorCallback, successCallback);
>>>> showAPrettyImageAndAskTheUserToWait();
>>>>
>>>> function errorCallback(error) {}
>>>> function successCallback() {
>>>>  getRidOfThePrettyImageAndRestartTheApp();
>>>> }
>>>>
>>>> just like you, i'm not sure if the error callback is useful at all, but
>>>> i
>>>> thought i'd add it to make the defragment() call look more like a
>>>> transaction. maybe we don't need it.
>>>>
>>>
>>> True, but this is a kind of operation that could very well just run on
>>> the background, with a single optional callback when it's done (the webpage
>>> can't do anything if an error is detected anyway).
>>
>> ok, so let's drop the errorCallback: vacuum([optional] successCallback);
>>
>>>
>>> The user agent would need to queue any subsequent transactions if a
>>> vacuum is running. I would consider it as an hint, and after all webpages
>>> that own references to the underlying data files are closed, would do a
>>> vacuum. So, if you have many tabs on gmail, and that a single gmail instance
>>> tries to do multiple vacuums, it would equiv to one single vacuum operation.
>>
>> what do we do if some databases are opened for the entire life of the
>> browser? for example, i open my browser which has myfavoriteapp.com set as
>> its homepage. myfavoriteapp.com immediately opens a DB, and i only close
>> that app when i close the browser. when would the browser vacuum
>> myfavoriteapp's DBs in this case?
>>
>> i think it's ok for the UA to vacuum some DBs automatically when it thinks
>> it's a good time to do so; however, if a platform supports the vacuum/defrag
>> call (i.e. if it doesn't treat it is a no-op), then i think a vacuum call
>> coming from the app should be immediately scheduled (yes, the subsequent
>> transactions would have to wait for the vacuuming to finish running). in
>> some cases, the apps know better than the UA when to vacuum their DBs.
>>
>> by the way, we should probably agree on a name for this call. which one do
>> you prefer? vacuum, defragment, defrag, something else? i don't have a
>> strong opinion.
>
> I think vacuum is fine since the spec is already tied to the SQLite SQL
> dialect.
> collectGarbage() is another possibility
> Go with whatever you think is most clear and accurate though.
> J
Received on Friday, 12 March 2010 21:31:46 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 18:49:37 GMT