[Freebase-discuss] Converting Freebase mid to integer

[Paul Houle]

       It's not crazy to be concerned about the efficiency of database 
keys.  On the other hand,  properly used mids are fairly efficient.

     Those who use sequential integer primary keys are almost always 
satisfied with performance;  some of them have tried a different kind of 
key and found performance degraded by orders of magnitude.

     The first explanation that comes to many people for this is the 
small size of the integer key,  which uses less RAM,  less disk space,  
less room in the cache,  fewer disk blocks,  etc.  This is a real 
effect,  but it's nowhere near large enough to account for the huge 
performance change.  This guy did a nice experiment

http://www.informit.com/articles/printerfriendly.aspx?p=25862

     who showed that sequential integer keys are drastically faster in 
Microsoft's SQL server than GUIDs,  not because of the the size,  but 
because they're sequential.  Once he started generating sequential 
"GUID" objects (breaking the GUID property of the objects) he found only 
a tiny difference compared with primary keys.