by "byte pairs" I mean byte arrays .. of course ... On Dec 22, 2011, at 4:20 PM, Aaron Cordova wrote:
> _You_ can think of it that way, cause you're Adam Fucsh, distributed database > expert extraordinaire, but that's not how the BigTable data model was > described by the original authors - "BigTable is a sparse, sorted, > distributed, multidimensional map", and most users do understand Accumulo to > be a map of keys to values where the keys are made up of a row, colfam, > colqual, colvis, and timestamp and the values are arbitrary byte pairs. > > To start explaining to people that Accumulo is a multi-map, or to actually > make it into a multi-map (i.e. allowing identical keys, where a key includes > the timestamp), would be a mistake, in my opinion. > > > On Dec 22, 2011, at 4:09 PM, Adam Fuchs wrote: > >> Sorry, I thought we were talking about users' perceptions of semantics. >> Bigtable also supports holding multiple versions of key/value pairs, so it >> can be thought of as having an underlying multi-map as well. >> >> Adam >> >> >> On Thu, Dec 22, 2011 at 4:04 PM, Aaron Cordova <[email protected]> wrote: >> >>> >>> On Dec 22, 2011, at 4:00 PM, Adam Fuchs wrote: >>> >>>> Timestamp doesn't usually make >>>> it into the uniqueness concept, from a user's perspective, even though >>> that >>>> affects the sort order of Keys. In fact, most users let Accumulo set the >>>> timestamp for them. I think your definition of uniqueness takes timestamp >>>> into account, and from that perspective what we're doing is sort of like >>>> providing a finer grained timestamp instead of using one timestamp for an >>>> entire Mutation (or for all Mutations that show up within a millisecond). >>> >>> Timestamps do define separate keys. This is not just my definition - this >>> is in the BigTable design as well as Hbase's, and likely every other >>> BigTable clone. >>> >>> >>> >
