On 11/25/21, 9:16 AM, "Mark Dilger" <mark.dil...@enterprisedb.com> wrote: >> On Nov 24, 2021, at 12:53 PM, Bossart, Nathan <bossa...@amazon.com> wrote: >> >> Another option we might consider is only checking for the >> HEAP_XMAX_LOCK_ONLY bit instead of everything in >> HEAP_XMAX_IS_LOCKED_ONLY. IIUC everything else is only expected to >> happen for upgrades from v9.2 or earlier, so it might be pretty rare >> at this point. Otherwise, I'll extract the exact bit pattern for the >> error message as you suggest. > >I would prefer to detect and report any "can't happen" bit patterns without >regard for how likely the pattern may be. The difficulty is in proving that a >bit pattern is disallowed. Just because you can't find a code path in the >current code base that would create a pattern doesn't mean it won't have >legitimately been created by some past release or upgrade path. As such, any >prohibitions explicitly in the backend, such as Asserts around a condition, >are really valuable. You can know that the pattern is disallowed, since the >server would Assert on it if encountered. > > Aside from that, I don't really buy the argument that databases upgraded from > v9.2 or earlier are rare. Even if servers *running* v9.2 or earlier are (or > become) rare, servers initialized that far back which have been upgraded one > or more times since then may be common.
Okay, I'll do it that way in the next revision. Nathan
