On 2020-Dec-01, Mark Dilger wrote: > 7) Run a SQL query that uses an index scan on the table and see that it > errors with something like: > > ERROR: could not read block 0 in file "base/13097/16391": read only 0 of > 8192 bytes > > I found it surprising that even when precisely zero of the tids in the > index exist in the table the index checks all come back clean.
Yeah, I've seen this kind of symptom in production databases (indexes pointing to non-existant heap pages). I think one useful cross-check that amcheck could do, is verify that if a heap page is referenced from the index, then the heap page must exist. Otherwise, it's a future index corruption of sorts: the old index entries will point to the wrong new heap tuples as soon as the table grows again.
