Your team manages a job-posting board (similar to Linkedin/Google-jobs) with daily incoming job-postings being scrapped/manually-added.
You are asked to design the architecture that helps answer queries on aggregate-salaries on multiple dimensions of the job.
Examples of dimensions: location, job-type, job-category, part-time/full-time, company, etc

Requirements:

• should be scalable
• response time should be near real-time (<100ms)

Some more details, after discussing with the interviewer:

• number of jobs of the order of ~1B
• number of requests for aggregate ~100QPS

I think I couldnt move ahead much in terms of the design that satisfies the requirements (especially the <100ms response-time).
How should someone proceed about this?