"Dann Corbit" <[EMAIL PROTECTED]> writes: > How many accounts are 90 days overdue? Bill says 78 and Frank says 82. > Who is right and how can we know?
If Bill and Frank look at exactly the same instant (ie, from read-only transactions started at the same time), they will get the same answer. If they are looking from transactions started at different times, or from transactions that have themselves added/removed rows, they won't necessarily get the same answer. That does not make either answer wrong, just a reflection of the snapshots they are seeing. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org