 

What is my identity burn factor vulnerability ri More DBA job interview questions and answers at
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(Continued from previous question...) What is my identity burn factor vulnerability right now in Sybase?
Identities are created type numeric, scale 0, and precision X. A precision of 9 means the largest identity value the server will be able to process is 10^91, or 1,000,000,0001, or 999,999,999. However, when it comes to Burning identities, the server will burn (based on the default value of 5000) .05% of 1,000,000,000 or 500,000 values in the case of a crash. (You may think an identity precision allowing for 1 Billion rows is optimistic, but I once saw a precision set at 14...then the database crashed and their identity values jumped 5 TRILLION. Needless to say they abandoned their original design. Even worse, SQL server defaults precision to 18 if you don't specify it upon table creation...that's a MINIMUM 10,000,000,000 jump in identity values upon a crash with the absolute minimum burn factor)
Burn value % of values # values burned during crash So, the absolute lowest amount of numbers you'll burn, assuming you configure the burn factor down to 1 (sp_configure "identity burning set factor", 1) and a precision of 9, is 100 values. (Continued on next question...)
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