Alexey Romanchuk <aromanchuk@xxxxxxxxxx> writes: > When i try to sum all size (live, dead and free) the sum is not equal > total size. For this table 206555428 + 3380295 + 13896816 = 223832539. > The difference between total and sum is 9410085. It is near 5%. pgstattuple is a bit simplistic: it doesn't count the page headers or item pointers at all. It looks to me like it also fails to consider the effects of alignment padding --- if a tuple's length is shown as 63, that's what it counts, even though the effective length is 64. (This might not be a problem in practice --- I'm not sure if the stored t_len has always been maxaligned or not.) regards, tom lane
