A quick run of that code on my laptop (RH 7.3, Athlon 1.something GHz, Sybase ASE 12.5.0.3) shows that I was wrong, and that batched commits almost certainly improve the performance for large inserts:

ac: 129 wallclock secs ( 2.77 usr +  0.40 sys =  3.17 CPU) @  3.15/s (
+n=10)
mc: 14 wallclock secs ( 2.05 usr +  0.40 sys =  2.45 CPU) @  4.08/s (n
+=10)
[download]

This is with no indexes on the tables.

Still, it's an interesting problem - I'll have to try this on some more serious iron, and with more data, and, ideally, with raw devices rather than disk devices that have O_DSYNC turned on.

Michael