Tom Lane wrote: > On the whole though I think we should let this idea go till 8.4; we have > a lot to deal with for 8.3 and a definite shortage of evidence that > advancing xmin will buy much. Mu gut feeling is that the above design > would save about enough in snapshot-copying costs to pay for its extra > management logic, but we won't come out ahead unless advancing xmin > intra-transaction really helps, and I'm not sure I believe that (except > in the special case of VACUUM, and we already have a solution for that, > which would be independent of this).
The improvement is going to be a win for multi-statement transactions --- the only question is how often are they long-running. It does seem best to put this on the TODO for 8.4, and I will do that now. The only thing that makes it tempting to get into 8.3 is that we could advertise this release as a major "space reuse" release because of HOT, autovacuum on by default, multiple autovacuum processes, and, if we added it, improved VACUUM for multi-statement transactions. -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend