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Fixes a SERVER_ERROR when value length is just under the max value length #272

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Fixes a SERVER_ERROR when value length is just under the max value length #272

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d863801
Fix for value length just under the max value size
mgetz Sep 16, 2015
ab861fa
The missing file to fix when value length is just under the max value…
mgetz Sep 16, 2015
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2 changes: 1 addition & 1 deletion lib/memcached.js
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Original file line number Diff line number Diff line change
Expand Up @@ -913,7 +913,7 @@ Client.config = {
value = Utils.escapeValue(value);

length = Buffer.byteLength(value);
if (length > this.maxValue) {
if (length + fullkey.length + 71 > this.maxValue) {
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A comment explaining the logic behind this (and the magic constant that is 71) would be appreciated :)

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Documentation I found said that 71 is the length of the metadata that memcache uses to store information about each key value pair. That may need to be adjusted or set as a system variable.

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Something to keep in mind is that memcache clients can also talk to Couchbase servers. I don't know what the limitations are there? In any case, I think a code comment or well chosen constant name would be nice.

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Thank you for the tips. We use it with both memcached and couchbase ourselves. I will do a bit more research and tweak the code accordingly.
Thanks!

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Thanks!

return privates.errorResponse(new Error('The length of the value is greater than ' + this.maxValue), callback);
}

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24 changes: 24 additions & 0 deletions test/memcached-get-set.test.js
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Expand Up @@ -625,4 +625,28 @@ describe("Memcached GET SET", function() {
done();
});
});

/**
* Set value size just under maximum amount of data (1MB),
* should trigger error, not crash. The actual value size to trigger the
* error should be value length + key length + length of metadata stored with the
* key value pair.
*/
it("set value length just under maximum data and check for correct error handling", function(done) {
var memcached = new Memcached(common.servers.single)
, message = new Array(32767).join('ThisIsMyTestMessageForThisData32')
, testnr = ++global.testnumbers
, callbacks = 0;
//Length of message is 1048512
memcached.set("test:" + testnr, message, 1000, function(error, ok){
++callbacks;

assert.equal(error, 'Error: The length of the value is greater than 1048576');
ok.should.be.false;

memcached.end(); // close connections
assert.equal(callbacks, 1);
done();
});
});
});