On Wed, 2007-01-10 at 10:37 -0500, Tom Lane wrote: > "Simon Riggs" <[EMAIL PROTECTED]> writes: > > I agree we could get this to Just Work by altering > > HeapTupleSatisfies...() functions so that their first test is > > if (TransactionIdIsCurrentTransactionId(xvac))
Oh? Sorry, I meant xmin not xvac at that point. Cut N Paste thinko. > > rather then > > if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED)) > > Huh? That doesn't make any sense at all. xvac wouldn't normally be > valid. > I don't want to put TransactionIdIsCurrentTransactionId into the main > path of the tqual routines if at all possible; it's not an especially > cheap test, particularly if deeply nested in subtransactions. Phew, well I'm relieved. Such a mainline change did make me nervous. > This would require rejiggering snapshots to include our own xid, see > comment for XidInSnapshot. That would add some distributed cost to > executions of XidInSnapshot for recently-committed tuples, but it would > avoid adding any cycles to the path taken for tuples committed before > the xmin horizon, which is the normal case that has to be kept fast. > > Haven't looked at whether an equivalent hack is possible for the other > tqual routines. Will check, thanks. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
