Thinking more about other systems, ISTM that Oracle can do this, as can any MVCC based system. OTOH DB2 and SQLServer take block level read locks, so they can do this too, but at major loss of concurrency and threat of deadlock. Having said that, *any* system that chose not to do this would be severely sub-optimal with buffer manager contention. So AFAICS they all need this optimization.
MySQL/Innodb would presumably do it also I wonder... Chris ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
