java - Any Idea/guess of how twitter saves its tweets in the database and updates it real-time -

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i making twitter type of website (not big twitter:), without using twitter api), have decide kind of database should use , how maintain in consistent state.

the main problem: suppose website twitter clone(that make question easier understand), if have user "a" has 100 friends , friends tweet same time "a" logs in @ point in time tweets fetched database, database being updated friends tweets => database in inconsistent state

q1> best solution it? maintain 2 database, use multi-threading etc? can explain in detail.

q2>what best database particular usage.

twitter uses nosql database called cassandra.
take closer here: apache cassandra


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