On 12/12/2011 08:46 PM, Daniel Farina wrote:
On Mon, Dec 12, 2011 at 5:36 PM, Andrew Dunstan<and...@dunslane.net> wrote:
The trouble with using JSON.parse() as a validator is that it's probably
doing way too much work. PLV8 is cool, and I keep trying to get enough time
to work on it more, but I don't think it's a substitute for a JSON type with
a purpose built validator and some native operations. I think these efforts
can continue in parallel.
Hmm. Maybe? While I'm sure things could be faster, we've had results
that are fast enough to be usable even with constant reparsing. Here
are some microbenchmarks I did some time ago where I tried to find the
overhead of calling JSON.parse and doing some really simple stuff in
V8 that I thought would maximize the amount of constant-time overhead:
https://gist.github.com/1150804
On my workstation, one core was able to do 130,000 JSON.parses + other
stuff necessary to create an index per second. One could maybe try to
improve the speed and memory footprint on large documents by having
validators that don't actually build the V8 representation and
possibly defining a space of operators that are known to build, by
induction, valid JSON without rechecks.
But in the end, I think there's already a class of problem where the
performance plv8 provides is already quite sufficient, and provides a
much more complete and familiar approach to the problem of how people
choose to navigate, project, and manipulate JSON documents.
I also haven't tried this for larger documents, as I was trying to get
a sense of how much time was spent in a few primitive operations, and
not testing performance with regard to document length.
Yes, I didn't mean to say it's not fast. For many cases I agree it is
probably fast enough.
But in the end PLV8 is likely to remain an addon - nice as it can be I
doubt the core team will want to add another PL to the core code,
especially one written in C++. If we want a JSON type built in, which
many people seem to want, we'll need to do it without the support of
PLV8, I think.
cheers
andrew
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