Ah didn't pick up on that but looks like he's storing JSON within position. Is there any strong reason for this or as Vladimir mentioned can you store the fields under "position" in separate columns?
Kurt Greaves k...@instaclustr.com www.instaclustr.com On 20 October 2016 at 08:17, Vladimir Yudovin <vla...@winguzone.com> wrote: > Hi Simon, > > Why *position *is text and not float? Text takes much more place. > Also speed and headings can be calculated basing on latest positions, so > you can also save them. If you really need it in data base you can save > them as floats, or compose single float value like speed.heading: 41.173 > (or opposite, heading.speed) and save column storage overhead. > > > Best regards, Vladimir Yudovin, > > *Winguzone <https://winguzone.com?from=list> - Hosted Cloud > CassandraLaunch your cluster in minutes.* > > > ---- On Thu, 20 Oct 2016 03:29:16 -0400*<wxn...@zjqunshuo.com > <wxn...@zjqunshuo.com>>* wrote ---- > > Hi All, > I'm trying to migrate my time series data which is GPS trace from mysql to > C*. I want a wide row to hold one day data. I designed the data model as > below. Please help to see if there is any problem. Any suggestion is > appreciated. > > Table Model: > CREATE TABLE cargts.eventdata ( > deviceid int, > date int, > event_time bigint, > position text, > PRIMARY KEY ((deviceid, date), event_time) > ) > > A slice of data: > cqlsh:cargts> SELECT * FROM eventdata WHERE deviceid = > 186628 and date = 20160928 LIMIT 10; > > deviceid | date | event_time | position > ----------+----------+---------------+---------------------- > ------------------------------------------------------------------- > 186628 | 20160928 | 1474992002000 | {"latitude": > 30.343443936386247,"longitude":120.08751351828943,"speed":41,"heading":48} > 186628 | 20160928 | 1474992012000 | {"latitude": > 30.34409508979662,"longitude":120.08840022183352,"speed":45,"heading":53} > 186628 | 20160928 | 1474992022000 | {"latitude": > 30.34461639856887,"longitude":120.08946100336443,"speed":28,"heading":65} > 186628 | 20160928 | 1474992032000 | {"latitude": > 30.34469478717028,"longitude":120.08973154015409,"speed":11,"heading":67} > 186628 | 20160928 | 1474992042000 | {"latitude": > 30.34494998929474,"longitude":120.09027263811151,"speed":19,"heading":47} > 186628 | 20160928 | 1474992052000 | {"latitude": > 30.346057349126617,"longitude":120.08967091817931,"speed": > 41,"heading":323} > 186628 | 20160928 | 1474992062000 | {"latitude" > :30.346997145708,"longitude":120.08883508853253,"speed":52,"heading":323} > 186628 | 20160928 | 1474992072000 | {"latitude": > 30.348131044340988,"longitude":120.08774702315581,"speed": > 65,"heading":321} > 186628 | 20160928 | 1474992082000 | {"latitude": > 30.349438164412838,"longitude":120.08652612959328,"speed": > 68,"heading":322} > > -Simon Wu > > >
