Distribution information in dbschema output

The distribution information in dbschema output describes the bins that are created for the distribution, the range of values in the table and in each bin, and the number of distinct values in each bin.

     (                        5)
  1: (  16,     7,           11)
  2: (  16,     6,           17)
  3: (  16,     8,           25)
  4: (  16,     8,           38)
  5: (  16,     7,           52)
  6: (  16,     8,           73)
  7: (  16,    12,           95)
  8: (  16,    12,          139)
  9: (  16,    11,          182)
 10: (  10,     5,          200)

The first value in the rightmost column is the smallest value in this column. In this example, it is 5.

The column on the left shows the bin number, in this case 1 through 10. The first number in parentheses shows how many values are in the bin. For this table, 10 percent of the total number of rows (165) is rounded down to 16. The first number is the same for all the bins except for the last. The last row might have a smaller value, indicating that it does not have as many row values. In this example, all the bins contain 16 rows except the last one, which contains 10.

The middle column within the parentheses indicates how many distinct values are contained in this bin. Thus, if there are 11 distinct values for a 16-value bin, it implies that one or more of those values are duplicated at least once.

The right column within the parentheses is the highest value in the bin. The highest value in the last bin is also the highest value in the table. For this example, the highest value in the last bin is 200.