Rest-Server Job API Perf Tests and Improvements

[suiguoxin]

DB table framework & frameworkHistory store the snapshot of framework as text. When the snapshot is used by Rest API, rest-server need to parse it as JSON and convert it to required schema. This can be very slow when the snapshot is large.

We test the performance of get job detail API after this fix in int bed and have the following results:

In the function convertFrameworkDetail , rest-server convert the framework snapshot to the required response schema.
This process is very slow. When lots of job/detail pages opened in the web-portal, rest-server can be overloaded.

Potential solutions:

• move the convert process to client side
• convert before write to DB
• ...