I wrote: > What that'd have to imply is that get_ps_display() messed up, > returning a bad pointer or a bad length. > A platform-specific problem in get_ps_display() seems plausible > enough. The apparent connection to a concurrent VACUUM FULL seems > pretty hard to explain that way ... but maybe that's a mirage.
If I understand correctly that you're only seeing this in v13 and HEAD, then it seems like bf68b79e5 (Refactor ps_status.c API) deserves a hard look. regards, tom lane