Обсуждение: new postgresql.conf
Just saw these: #default_transaction_isolation = 'read committed' #default_transaction_read_only = false Does the second option control the new read only transaction mode? I thought 'read only' was just a new level of transaction isolation (ie. one of the 4 sql standard ones), so why does it need its own GUC var? Chris
On Mon, 28 Jul 2003, Christopher Kings-Lynne wrote: > Just saw these: > > #default_transaction_isolation = 'read committed' > #default_transaction_read_only = false > > Does the second option control the new read only transaction mode? I > thought 'read only' was just a new level of transaction isolation (ie. one > of the 4 sql standard ones), so why does it need its own GUC var? It is a transaction access mode, not an isolation level. ansi sql supports two modes: read only and read write. Gavin
"Christopher Kings-Lynne" <chriskl@familyhealth.com.au> writes: > Just saw these: > #default_transaction_isolation = 'read committed' > #default_transaction_read_only = false > Does the second option control the new read only transaction mode? Yes. > I thought 'read only' was just a new level of transaction isolation (ie. one > of the 4 sql standard ones), so why does it need its own GUC var? No, it's orthogonal to isolation. A read-only transaction could sensibly want either READ COMMITTED or SERIALIZABLE behavior, depending on whether it wants to see the effects of commits while it's in progress. regards, tom lane