Two other options that mention span state percentage of total log space:
oldest_active_transaction_pct– returns a number from 0 to 100 indicating the span of the oldest active transaction in percentage of total log space
stp_span_pct– returns a number from 0 to 100 indicating the span of secondary truncation point to the end of log with respect to total log space
Unfortunately the example they give in the manuals doesn't have much context and is confusing as the '2' could answer your question about front+end = 2 pages:
================================
select loginfo(dbid, ‘xactspanbyspid’, spid)
spid log_span_pct
----------------------
15 2
================================
Since none of the other cases support the idea of front+end=2 (which would always be the case, right?), my guess would be that xactspanbyspid gives a percentage of the log consumed by a particular spid.
'course the easiest way to verify would be to run some tests. [When in doubt, try it out!]
