Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> You can't change xmin --- this would break visibility tests.
> Basically the phantom xid's are a shorthand for saying the tuple was > created by xid1 and deleted by xid2, both part of the same main > transaction. That would be fine if the shorthand were readable, but it's not. > A cursor looking at the rows has to recognize the xid is a phantom (via > pg_subtrans) and look up the creation xid. And it will find that how? Imagine that the creating transaction is itself a subtransaction, and the deleting one is a few nesting levels further down. I don't see how the tuple is going to carry enough information to let you determine what's what, if the deleting subxact overwrites the creating one's XID. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]