Known Issues and Limitations
We continuously improve the product. Please be aware of the following known issues and limitations.
UI
- You can use a mobile browser to sign up for Timeplus Cloud. But only Google Chrome desktop browser is supported to use the Timeplus Console.
- Users in the same workspace will see all activity history and definitions, such as views, sinks, dashboards. Fine grained access control for user/group/role will be provided in the future.
Backend
- When you define a stream, a materialized view, or a sink, you should avoid using
window_start
andwindow_end
as the column names. This will conflict with the dynamic column nameswindow_start
andwindow_end
fortumble
,hop
,session
windows. You can create alias while creating materialized views, e.g.select window_start as windowStart, window_end as windowEnd, count(*) as cnt from tumble(stream,10s) group by window_start, window_end
- You can save JSON documents either in
string
orjson
column types.string
type accepts any JSON schema or even invalid JSON. It also works well with dynamic schema, e.g.{"type":"a","payload":{"id":1,"attr1":0.1}}
and{"type":"b","payload":{"id":"2","attr2":true}}
While thejson
column type works best with fixed JSON schema, with better query performance and more efficient storage. For the above example, it will try to change the data type to support existing data.payload.id
will be inint
since the first event is1
. Then it will change tostring
, to support both1
and"2"
. If you define the column asjson
, running non-streaming query for the dataset will get astring
type forpayload.id
However data type cannot be changed during the execution of streaming queries. If you runSELECT col.payload.id as id FROM json_stream
and insert{.."payload":{"id":1..}
the first column in the streaming query result will be inint
. Then if the future event is{.."payload":{"id":"2"..}
, we cannot dynamically change this column fromint
tostring
, thus the streaming query will fail. In short, bothstring
andjson
work great for non-streaming query. If the JSON documents with dynamic schema, it's recommended to define the column instring
type.