But epsilon is the error from a SINGLE operation if we add 10^6 numbers together, the possible error is nearly 10^6 as large, so that error is on the order of 1e-01 Unless you think that SQLite should have a SUM operation (and the like), with a defined rounding point to apply after every (or every so often) operation, this error will accumulate over the full sum, so you need to compute it for the full sum.