Which begs the question, what is more important, the old/vacuumed data, or the current valid data?
If someone can hack into the freed data, then they certainly have the ability to hack into the current valid data.On Wed, Nov 18, 2015 at 3:13 PM, Alvaro Herrera <alvherre@xxxxxxxxxxxxxxx> wrote:
David G. Johnston wrote:
> On Wed, Nov 18, 2015 at 12:45 PM, Day, David <dday@xxxxxxxxxx> wrote:
> > I believe the concern, based on my current understanding of postgres
> > inner workings, is that when a dead tuple is reclaimed by vacuuming: Is
> > that reclaimed space initialized in some fashion that would shred any
> > sensitive data that was formerly there to any inspection by the
> > subsequent owner of that disk page ? ( zeroization )
No. Ultimately, space occupied by dead tuples is "freed" in
PageRepairFragmentation(), src/backend/storage/page/bufpage.c;
the contents of the tuples are shuffled to "defragment" the free space,
but the free space is not zeroed. You could certainly try to read the
unused page and extract some data from there.
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