On 30 Aug 2013, at 16:35, Esteban Lorenzano <esteba...@gmail.com> wrote:
> > On Aug 29, 2013, at 5:08 PM, Sven Van Caekenberghe <s...@stfx.eu> wrote: > >> >> On 29 Aug 2013, at 16:51, Esteban Lorenzano <esteba...@gmail.com> wrote: >> >>> hi >>> >>> well... I've never been happy on using the UUID generator for my keys, but >>> is the fastest option I found. >>> There are, of course, alternatives: >>> >>> 1) Using your own number generator (sequential, or whatever). Problem with >>> that is that is image based, then you need a persistence strategy... then >>> you are slow. >>> 2) then you can use your own procedure in mongo... with same problem than >>> (1) >>> 3) you could use timestamp. but TimeStamps are slow :( >>> >>> anyway... I open to ideas :) >>> >>> in the mean time, you can check if your UUID generator is using the >>> primitive or not. In you are not, you have more possibilities of having a >>> collision. >> >> Yes, the Smalltalk code (type 4 UUID) is just a random number that is >> computed in a complex way. >> >> What does the primitive actually do ? Is it different ? > > the primitive uses the clock ticks to produce an UUID... you shouldn't have > repeated numbers that way... but well, it depends on the platform > implementation also. I don't like plugins because it is some much harder for everyone to look at the implementation, while everybody thinks some magic happens there, and often the truth is quite disappointing. Maybe the resolution of #primUTCMicrosecondsClock is not high enough ? >>> Esteban >>> >>> On Aug 29, 2013, at 11:27 AM, Sabine Knöfel <sabine.knoe...@gmail.com> >>> wrote: >>> >>>> Hi Esteban, All, >>>> >>>> I was proceeding to seach for the reason of the problem I described >>>> yesterday. >>>> >>>> I added some debugging code into VOMongoSerializer>>ensurePersisted: and >>>> the >>>> problem I described, did NOT occur. >>>> >>>> That made the whole process slower...and I had an idea.... >>>> >>>> I was looking into >>UUIDGenerator default makeSeed. >>>> Then I tried the following code: >>>> >>>> |theOld theNew| >>>> >>>> 100000000 timesRepeat: [ >>>> theNew := UUIDGenerator default makeSeed. >>>> theNew = theOld ifTrue: [self halt]. >>>> theOld := theNew] >>>> >>>> The debugger came up! Doesn't that mean that, if the code is run very fast, >>>> there are double OIDs generated?! >>>> >>>> In my case, the objects for country and currency are very lightweight and >>>> so, they are created very fast. Also, the error occured much more often >>>> within my fast production EC2 instance as at my (old and slow) development >>>> pc. >>>> >>>> Important: I work with windows and so >>makeUnixSeed returns nil... :-) >>>> >>>> What is your opinion about that? >>>> >>>> Sabine >>>> >>>> >>>> >>>> -- >>>> View this message in context: >>>> http://forum.world.st/voyage-mongo-randomly-wrong-OIDs-tp4705396p4705603.html >>>> Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. >>>> >>> >>> >> >> > >
