Many Facebook users were unable to access the social networking site for up to two and a half hours on Thursday, the worst outage the website has had in over four years, Facebook said in a posting.
The problems were traced back to a change made by Facebook in one of its systems.
The change was made to a piece of data that was called upon whenever an error-checking routine found invalid data in Facebook's system. The piece of data was itself interpreted as invalid, which caused the system to try and replace it with the same piece of data and so a feedback loop began.
The loop resulted in hundreds of thousands of queries per second being sent to Facebook's database cluster, overwhelming the system.
More: http://www.computerworld.com/s/article/9187738/
The problems were traced back to a change made by Facebook in one of its systems.
The change was made to a piece of data that was called upon whenever an error-checking routine found invalid data in Facebook's system. The piece of data was itself interpreted as invalid, which caused the system to try and replace it with the same piece of data and so a feedback loop began.
The loop resulted in hundreds of thousands of queries per second being sent to Facebook's database cluster, overwhelming the system.
More: http://www.computerworld.com/s/article/9187738/