There is now: https://pulp.plan.io/issues/3848
David On Wed, Jul 11, 2018 at 4:23 PM Brian Bouterse <bbout...@redhat.com> wrote: > A 30% improvement I think is a good case for integers over uuids. > > Is there a ticket tracking that change? > > On Wed, Jul 11, 2018 at 3:55 PM, Daniel Alley <dal...@redhat.com> wrote: > >> w/ creating 400,000 units, the non-uuid PK is 30% faster at 42.22 seconds >> vs. 55.98 seconds. >> >> w/ searching through the same 400,000 units, performance is still about >> 30% faster. Doing a filter for file content units that have a >> relative_path__startswith={some random letter} (I put UUIDs in all the >> fields) takes about 0.44 seconds if the model has a UUID pk and about 0.33 >> seconds if the model has a default Django auto-incrementing PK. >> >> On Wed, Jul 11, 2018 at 11:03 AM, Daniel Alley <dal...@redhat.com> wrote: >> >>> So, since I've already been working on some Pulp 3 benchmarking I >>> decided to go ahead and benchmark this to get some actual data. >>> >>> Disclaimer: The following data is using bulk_create() with a modified, >>> flat, non-inheriting content model, not the current multi-table inherited >>> content model we're currently using. It's also using bulk_create() which >>> we are not currently using in Pulp 3, but likely will end up using >>> eventually. >>> >>> Using normal IDs instead of UUIDs was between 13% and 25% faster with >>> 15,000 units. 15,000 units isn't really a sufficient value to actually >>> test index performance, so I'm rerunning it with a few hundred thousand >>> units, but that will take a substantial amount of time to run. I'll follow >>> up later. >>> >>> As far as search/update performance goes, that probably has better >>> margins than just insert performance, but I'll need to write new code to >>> benchmark that properly. >>> >>> On Thu, May 24, 2018 at 11:52 AM, David Davis <davidda...@redhat.com> >>> wrote: >>> >>>> Agreed on performance. Doing some more Googling seems to have mixed >>>> opinions on whether UUIDs performance is worse or not. If this is a >>>> significant reason to switch, I agree we should test out the performance. >>>> >>>> Regarding the disk size, I think using UUIDs is cumulative. Larger PKs >>>> mean bigger index sizes, bigger FKs, etc. I agree that it’s probably not a >>>> major concern but I wouldn’t say it’s trivial. >>>> >>>> David >>>> >>>> On Thu, May 24, 2018 at 11:27 AM, Sean Myers <sean.my...@redhat.com> >>>> wrote: >>>> >>>>> Responses inline. >>>>> >>>>> On 05/23/2018 02:26 PM, David Davis wrote: >>>>> > Before the release of Pulp 3.0 GA, I think it’s worth just checking >>>>> in to >>>>> > make sure we want to use UUIDs over integer based IDs. Changing from >>>>> UUIDs >>>>> > to ints would be a very easy change at this point (1-2 lines of >>>>> code) but >>>>> > after GA ships, it would be hard if not impossible to switch. >>>>> > >>>>> > I think there are a number of reasons why we might want to consider >>>>> integer >>>>> > IDs: >>>>> > >>>>> > - Better performance all around for inserts[0], searches, indexing, >>>>> etc >>>>> >>>>> I don't really care either way, but it's worth pointing out that UUIDs >>>>> are >>>>> integers (in the sense that the entire internet can be reduced to a >>>>> single >>>>> integer since it's all just bits). To the best of my knowledge they >>>>> are equally >>>>> performant to integers and stored in similar ways in Postgres. >>>>> >>>>> You linked a MySQL experiment, done using a version of MySQL that is >>>>> nearly 10 >>>>> years old. If there are concerns about the performance of UUID PKs vs. >>>>> int PKs >>>>> in Pulp, we should compare apples to apples and profile Pulp using >>>>> UUID PKs, >>>>> profile Pulp using integer PKs, and then compare the two. >>>>> >>>>> In my small-scale testing (100,000 randomly generated content rows of a >>>>> proto-RPM content model, 1000 repositories randomly related to each, >>>>> no db funny >>>>> business beyond enforced uniqueness constraints), there was either no >>>>> difference, or what difference there was fell into the margin of error. >>>>> >>>>> > - Less storage required (4 bytes for int vs 16 byes for UUIDs) >>>>> >>>>> Well, okay...UUIDs are *huge* integers. But it's the length of an IPv6 >>>>> address >>>>> vs. the length of an IPv4 address. While it's true that 4 < 16, both >>>>> are still >>>>> pretty small. Trivially so, I think. >>>>> >>>>> Without taking relations into account, a table with a million rows >>>>> should be a >>>>> little less than twelve mega(mebi)bytes larger. Even at scale, the size >>>>> difference is negligible, especially when compared to the size on disk >>>>> of the >>>>> actual content you'd need to be storing that those million rows >>>>> represent. >>>>> >>>>> > - Hrefs would be shorter (e.g. /pulp/api/v3/repositories/1/) >>>>> > - In line with other apps like Katello >>>>> >>>>> I think these two are definitely worth considering, though. >>>>> >>>>> > There are some downsides to consider though: >>>>> > >>>>> > - Integer ids expose info like how many records there are >>>>> >>>>> This was the main intent, if I recall correctly. UUID PKs are not: >>>>> - monotonically increasing >>>>> - variably sized (string length, not bit length) >>>>> >>>>> So an objects PK doesn't give you any indication of how many other >>>>> objects may >>>>> be in the same collection, and while the Hrefs are long, for any given >>>>> resource >>>>> they will always be a predictable size. >>>>> >>>>> The major downside is really that they're a pain in the butt to type >>>>> out when >>>>> compared to int PKs, so if users are in a situation where they do have >>>>> to type >>>>> these things out, I think something has gone wrong. >>>>> >>>>> If users typing in PKs can't be avoided, UUIDs probably should be >>>>> avoided. I >>>>> recognize that this is effectively a restatement of "Hrefs would be >>>>> shorter" in >>>>> the context of how that impacts the user. >>>>> >>>>> > - Can’t support sharding or multiple dbs (are we ever going to need >>>>> this?) >>>>> >>>>> A very good question. To the best of my recollection this was never >>>>> stated as a >>>>> hard requirement; it was only ever mentioned like it is here, as a >>>>> potential >>>>> positive side-effect of UUID keys. If collision-avoidance is not >>>>> desired, and >>>>> will certainly never be desired, then a normal integer field would >>>>> likely be a >>>>> less astonishing[0] user experience, and therefore a better user >>>>> experience. >>>>> >>>>> [0]: https://en.wikipedia.org/wiki/Principle_of_least_astonishment >>>>> >>>>> >>>>> _______________________________________________ >>>>> Pulp-dev mailing list >>>>> Pulp-dev@redhat.com >>>>> https://www.redhat.com/mailman/listinfo/pulp-dev >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> Pulp-dev mailing list >>>> Pulp-dev@redhat.com >>>> https://www.redhat.com/mailman/listinfo/pulp-dev >>>> >>>> >>> >> >> _______________________________________________ >> Pulp-dev mailing list >> Pulp-dev@redhat.com >> https://www.redhat.com/mailman/listinfo/pulp-dev >> >> >
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