Thanks Gregory, thanks Simon. I'm trying to read the tqual.c source file to better understand. On Wednesday 25 July 2007 Gregory Stark's cat, walking on the keyboard, wrote: > If you really want to understand how snapshots work at this level you could > read (slowly -- it's pretty dense stuff) through > src/backend/utils/time/tqual.c:HeapTupleSatisfiesMVCC() I don't find it, I think you mean HeapTupleSatisfiesNow and HeapTupleSatisfiesSnapshot. Just for confirmation: the relfrozenxid of a fresh table is the xid of the transaction that created it, isn't it? Luca
