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Re: Two years on and still no sensible web storage solutions exist

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Mon, 12 Nov 2012 14:46:50 -0800
Message-ID: <50A17C5A.1070309@mit.edu>
To: Florian Bösch <pyalot@gmail.com>
CC: Webapps WG <public-webapps@w3.org>
On 11/12/12 1:56 PM, Florian Bösch wrote:
> In FF 16.0.2 on linux, 50mb put takes about 100ms and get takes about 500ms.

For what it's worth, I did some measuring, and the main performance cost 
centers for the write (the CPU-intensive ones, not the disk access) seem 
to be:

1)  Making a copy of the data to put in the database (because the 
database write happens on a background thread and we want to return 
control to JS before we do that to avoid blocking the main thread, so 
have to copy the data).

2)  Compressing the data (we store it compressed on disk).

For the read it's decompressing and then copying out of the resulting 
data structure into the JS engine's heap for the typed array.

It might be possible to mitigate the copying costs, especially if 
indexeddb had a way to indicate that things should be transferred, not 
copied, similar to postMessage.

-Boris
Received on Monday, 12 November 2012 22:47:21 GMT

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