Restrict String size when data is being inserted into cache

[v3g42]

Failed to insert record in Cache: "events", Error: Query(InsertValue(BadValSize)). Usually this happens if primary key is wrongly specified

Right now if string is long, dozer panics.

• One event cannot bring the pipeline.
• Secondly if the string is longer, maybe we can trim ?

[chubei]

Yes we can do trimming. Pipeline crash is bad.