_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. >> >> >>
