> Also, does WAL offer instantaneous crash recovery like no-overwrite?
No, but it offers < 1 fsync per commit, instead of fsyncing every
changed table/index...
+ rollback changes of aborted transactions.
And, btw, WAL can live with non-overwriting smgr without problem -
why do you oppose them?
Also, try to power off while inserts into table with indices -
indices will be broken...
Vadim