Please find attached a patch to enable data checksums by default.
Currently, initdb only enables data checksums if passed the --data-checksums or -k argument. There was some hesitation years ago when this feature was first added, leading to the current situation where the default is off. However, many years later, there is wide consensus that this is an extraordinarily safe, desirable setting. Indeed, most (if not all) of the major commercial and open source Postgres systems currently turn this on by default. I posit you would be hard-pressed to find many systems these days in which it has NOT been turned on. So basically we have a de-facto standard, and I think it's time we flipped the switch to make it on by default.
The patch is simple enough: literally flipping the boolean inside of initdb.c, and adding a new argument '--no-data-checksums' for those instances that truly want the old behavior. One place that still needs the old behavior is our internal tests for pg_checksums and pg_amcheck, so I added a new argument to init() in PostgreSQL/Test/Cluster.pm to allow those to still pass their tests.
This is just the default - people are still more than welcome to turn it off with the new flag. The pg_checksums program is another option that actually argues for having the default "on", as switching to "off" once initdb has been run is trivial.
Yes, I am aware of the previous discussions on this, but the world moves fast - wal compression is better than in the past, vacuum is better now, and data-checksums being on is such a complete default in the wild, it feels weird and a disservice that we are not running all our tests like that.
Cheers,
Greg
