so I just started reading a book about "Mongo schema design" and am currently reading the portion about MMAP and fragmentation.

From what I understood there are different ways to avoid database fragmentation. What I wanted to know, however is if the character limit in platforms like twitter a way they found to counter or solve the issue of database fragmentation and if so what would be another solution that does not involve tweaking the front end?


1 Answer 1


The original character limit in twitter was because it started out as a micro-blogging platform with the option to update via SMS. SMS messages had a limit of 160 bytes. The 140 limit on the message length is because the extra metadata (to identify the user) was up to 20 characters long.

It had nothing to do with things that could affect internal or external fragmentation (rows/page, dynamic/static row sizes, excess page splitting due to key values effectively in random order, ...) or other concerns of the backend database design.

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