Aggregate optimization settings

On the Optimization tab you specify the following.

Keys are contiguous. Select this option if you know that all records with the same key values are grouped together in the input (for example, if the input is sorted on the key fields). Doing so can improve performance.

Allow approximation for Median and Quartiles. The Order statistics (Median, 1st Quartile, and 3rd Quartile) are currently not supported when processing data in Analytic Server. If you are using Analytic Server you can select this check box to use an approximated value for these statistics instead which is calculated by binning the data and then computing an estimate for the statistic based on the distribution across the bins. By default, this option is unchecked.

Number of bins. Only available if you select the Allow approximation for Median and Quartiles check box. Select the number of bins to be used when estimating the statistic; the number of bins affects the Maximum error %. By default, the number of bins is 1000, which corresponds to a maximum error of 0.1 percent of the range.