Bruce Momjian <[EMAIL PROTECTED]> writes: > I should add that I am not prepared to overhaul the pg_clog file format > as part of adding subtransactions for 7.4. I can do the tid/sequential scan > method for abort, or the single-lock method described.
If you think that changing the pg_clog file format would be harder than either of those other ideas, I think you're very badly mistaken. pg_clog is touched only by one rather simple module. I think the other methods will be completely unacceptable from a performance point of view. They could maybe work if subtransactions were a seldom-used feature; but the people who want to use 'em are mostly talking about a subtransaction for *every* command. If you design your implementation on the assumption that subtransactions are infrequent, it will be unusably slow. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org