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RE: [IndexedDB] Passing an empty array to IDBDatabase.transaction

From: Israel Hilerio <israelh@microsoft.com>
Date: Fri, 14 Oct 2011 21:27:17 +0000
To: "Jonas Sicking (jonas@sicking.cc)" <jonas@sicking.cc>
CC: "ben turner (bent.mozilla@gmail.com)" <bent.mozilla@gmail.com>, "Jonas Sicking (jonas@sicking.cc)" <jonas@sicking.cc>, "public-webapps@w3.org" <public-webapps@w3.org>, Tom Bolds <thombo@microsoft.com>, "Adam Herchenroether" <aherchen@microsoft.com>, Victor Ngo <vicngo@microsoft.com>
Message-ID: <F695AF7AA77CC745A271AD0F61BBC61E3F4CB695@TK5EX14MBXC117.redmond.corp.microsoft.com>
On Monday, October 10, 2011 10:15 AM, Israel Hilerio wrote:
> On Monday, October 10, 2011 9:46 AM, Jonas Sicking wrote:
> > On Fri, Oct 7, 2011 at 11:51 AM, Israel Hilerio
> > <israelh@microsoft.com>
> > wrote:
> > > On Thursday, October 06, 2011 5:44 PM, Jonas Sicking wrote:
> > >> Hi All,
> > >>
> > >> In both the Firefox and the Chrome implementation you can pass an
> > >> empty array to IDBDatabase.transaction in order to create a
> > >> transaction which has a scope that covers all objectStores in the
> > >> database. I.e. you can do something like:
> > >>
> > >> trans = db.transaction([]);
> > >> trans.objectStore(<any objectstore here>);
> > >>
> > >> (Note that this is *not* a dynamic scoped transaction, it's still a
> > >> static scope that covers the whole database).
> > >>
> > >> In other words, these implementations treat the following two lines
> > >> as
> > >> equivalent:
> > >>
> > >> trans = db.transaction([]);
> > >> trans = db.transaction(db.objectStoreNames);
> > >>
> > >> This, however, is not specified behavior. According to the spec as
> > >> it is now the transaction should be created with an empty scope.
> > >>
> > >> I suspect both Mozilla and Google implemented it this way because
> > >> we had discussions about this syntax on the list. However
> > >> apparently this syntax never made it into the spec. I don't recall why.
> > >>
> > >> I'm personally not a big fan of this syntax. My concern is that it
> > >> makes it easier to create a widely scoped transaction which has
> > >> less ability to run in parallel with other transactions, than to
> > >> create a transaction with as narrow scope as possible. And passing
> > db.objectStoreNames is always possible.
> > >>
> > >> What do people think we should do? Should we add this behavior to
> > >> the spec? Or are implementations willing to remove it?
> > >>
> > >> / Jonas
> > >>
> > >
> > > Our implementation interprets the empty array as an empty scope.  We
> > allow the transaction to be created but we throw a NOT_FOUND_ERR when
> > trying to access any object stores.
> > > I vote for not having this behavior :-).
> >
> > Hi Israel,
> >
> > I just realized that I might have misinterpreted your response.
> >
> > Are you saying that you think that passing an empty-array should
> > produce a transaction with an empty scope (like in IEs implementation
> > and as described by the spec currently), or a transaction with every
> > objectStore in scope (like in Firefox and chrome)?
> >
> > / Jonas
> >
> 
> We don't do it like FF or chrome.  We create the transaction but it has an
> empty scope transaction.  Therefore, whenever you try to access an object
> store we throw an exception.  Based on what Hans said, it seems we're all in
> agreement.
> 
> Also, I like Ben's suggestion of not allowing these transactions to be created in
> the first place and throwing an exception during their creation.
> 
> Israel
> 

What type of exception should we throw when trying to create a transaction with an empty scope (NotFoundError, TypeError, or other)?

Israel
Received on Friday, 14 October 2011 21:27:47 GMT

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