Hello hackers,
Using Svace* I think I've found a little bug in src/backend/utils/mmgr/dsa.c.
This bug is presented in REL_12_STABLE, REL_13_STABLE, REL_14_STABLE,
REL_15_STABLE, REL_16_STABLE and master. I see that it was introduced together
with dynamic shared memory areas in the commit 13df76a537cca3b8884911d8fdf7c89a457a8dd3.
I also see that at least two people have encountered this fprintf output.
fprintf(stderr,
" segment bin %zu (at least %d contiguous pages free):\n",
i, 1 << (i - 1));
In case i equals zero user will get "at least -2147483648 contiguous pages free".
I believe that this is a mistake, and fprintf should print "at least 0 contiguous pages free"
in case i equals zero.
The patch that has a fix of this is attached.
Juniour Software Developer at Postgres Professional