This commit is contained in:
Sears Russell 2005-03-26 02:31:58 +00:00
parent 2049da3b13
commit ed03f9c515

View file

@ -1908,12 +1908,12 @@ of object serialization. The first is to use a single transaction for
each object modification, avoiding the cost of generating or logging
any UNDO records. The second option is to assume that the
application will provide a custom UNDO for the delta,
which requires a log entry for each update,
which increases the size of the log entry generated by each update,
but still avoids the need to read or update the page
file.
The third option is to relax the atomicity requirements for a set of
object updates, and again avoid generating any UNDO records. This
object updates and again avoid generating any UNDO records. This
assumes that the application cannot abort individual updates,
and is willing to
accept that some prefix of logged but uncommitted updates may
@ -1944,7 +1944,7 @@ by the page LSN so that unrelated updates remain independent.
Recovery work essentially the same as before, except that we need to
use RSNs to calculate the earliest allowed point for log truncation
(so as to not lose an older record update). In the implementation, we
(so as to not lose an older record update). In practice, we
also periodically flush the object cache to move the truncation point
forward, but this is not required.