Yep, this is JavaScript's rather strange idea to represent all Numbers
as double-precision floating point. Large integers get corrupted in
the process -- you only get 15 digits of precision. My workaround has
been to save these big integers as strings.
As Chris alluded to, the document itself should be OK, but all
roundtrips through SpiderMonkey will not represent the value correctly.
We need to put this in the wiki at some point. Best,
Adam
On Nov 7, 2009, at 6:23 PM, Chris Anderson wrote:
Roger,
Can you confirm for me that when you load the doc directly (not via a
view) the number is unchanged? I've tested CouchDB with much larger #s
(but not in a while).
If the doc round-trips properly that means the precision is being lost
inside the spidermonkey view engine, not in our Erlang JSON handling.
Thanks,
Chris
On Sat, Nov 7, 2009 at 2:58 PM, Roger Binns <[email protected]>
wrote:
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As part of my testing I create a document containing an integer
that is the
largest that can be represented in a signed 64 bit quantity. On
getting the
document back from couchdb it is an even larger number! I used
Wireshark to
make sure this is not some other intermediary component messing up.
I used _bulk_docs:
{"docs": [{"_id": "92ba99b6683541bc8d27558f219abfd1", "val":
9223372036854775807}]}
Response:
HTTP/1.1 201 Created
Reading back again (via a view):
{"total_rows":1,"offset":0,"rows":[
{"id":"92ba99b6683541bc8d27558f219abfd1","key":null,"value":
["1-88f82719afe029f8f16597bb0992f115",9223372036854776000]}
]}
What I sent: 9223372036854775807
Get back: 9223372036854776000.
The number coming back can't be represented in a 64 bit signed
quantity
which then trips various things in my test suite.
Roger
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--
Chris Anderson
http://jchrisa.net
http://couch.io
