- From: Jonas Sicking <jonas@sicking.cc>
- Date: Wed, 9 Jun 2010 15:52:29 -0700
- To: "Tab Atkins Jr." <jackalmage@gmail.com>
- Cc: Laxmi Narsimha Rao Oruganti <Laxmi.Oruganti@microsoft.com>, Jeremy Orlow <jorlow@chromium.org>, Shawn Wilsher <sdwilsh@mozilla.com>, Webapps WG <public-webapps@w3.org>
On Wed, Jun 9, 2010 at 3:36 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote: > On Wed, Jun 9, 2010 at 3:27 PM, Jonas Sicking <jonas@sicking.cc> wrote: >> I'm well aware of this. My argument is that I think we'll see people >> write code like this: >> >> results = []; >> db.objectStore("foo").openCursor(range).onsuccess = function(e) { >> var cursor = e.result; >> if (!cursor) { >> weAreDone(results); >> } >> results.push(cursor.value); >> cursor.continue(); >> } >> >> While the indexedDB implementation doesn't hold much data in memory at >> a time, the webpage will hold just as much as if we had had a getAll >> function. Thus we havn't actually improved anything, only forced the >> author to write more code. >> >> >> Put it another way: The raised concern is that people won't think >> about the fact that getAll can load a lot of data into memory. And the >> proposed solution is to remove the getAll function and tell people to >> use openCursor. However if they weren't thinking about that a lot of >> data will be in memory at one time, then why wouldn't they write code >> like the above? Which results as just as much data being in memory? > > At the very least, explicitly loading things into an honest-to-god > array can make it more obvious that you're eating memory in the form > of a big array, as opposed to just a "magically transform my blob of > data into something more convenient". I don't fully understand this. getAll also returns an honest-to-god array. > (That said, I dislike cursors and explicitly avoid them in my own > code. In the PHP db abstraction layer I wrote for myself, every query > slurps the results into an array and just returns that - I don't give > myself any access to the cursor at all. I probably like this better > simply because I can easily foreach through an array, while I can't do > the same with a cursor unless I write some moderately more complex > code. I hate using while loops when foreach is beckoning to me.) This is what I'd expect many/most people to do. / Jonas
Received on Wednesday, 9 June 2010 22:53:22 UTC