Hi,
this is the second improvement proposed in the thread [1] about ext4
data loss issue. It adds another field to control file, tracking the
last known WAL segment. This does not eliminate the data loss, just the
silent part of it when the last segment gets lost (due to forgetting the
rename, deleting it by mistake or whatever). The patch makes sure the
cluster refuses to start if that happens.
[1] http://www.postgresql.org/message-id/56583BDD.9060302@2ndquadrant.com
It's a fairly simple patch, but obviously it touches very complex part
of the code. I'll add it to 2016-01 CF.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services