Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> There are other problems besides WAL bloat, too.
> I assumed the UNDO would have had to be in a separate place, or allow
> compression of the WAL file to keep needed UNDO stuff but get rid of
> unneeded stuff --- it was all quite complicated.
There is a mechanism in the XLOG code to distinguish "in transaction"
from "out of transaction" WAL entries. The thing I had not realized
before working on the btree code is that that mechanism is inadequate
for UNDO.
regards, tom lane
