Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> writes: > Gregory Stark wrote: > > Tom Lane <tgl@xxxxxxxxxxxxx> writes: > > > > > Matteo Sgalaberni <sgala@xxxxxxxxx> writes: > > > > Good to know this...but why this behaviour? it'is lovely...:) > > > > > > Open transactions are tracked across the whole cluster. This is > > > necessary when vacuuming shared catalogs. In principle we could > > > track per-database xmin values as well, but the distributed overhead > > > that'd be added to *every* GetSnapshotData call is a bit worrisome. > > > > Don't we do that now in CVS (ie, in 8.2)? > > No, we don't. I must be misunderstanding Tom's comment then. What I'm referring to is lazy_vacuum_rel() calls vacuum_set_xid_limits with the relisshared flag of the relation. vacuum_set_xid_limits passes that to GetOldestXmin as the allDbs parameter. GetOldestXmin ignores transactions not connected to the same database unless allDbs is true. -- greg
