Chapman Flack <c...@anastigmatix.net> writes: > On 03/27/18 22:10, Michael Paquier wrote: >> Here you go for one example: >> https://sourceforge.net/projects/pglesslog/
> In any case, from my study of the commit, it is hard for me to see an issue. > The code comment says: "mark the header to indicate that WAL records > beginning in this page have removable backup blocks." Yeah, that commit just moved a flag from individual WAL records to page headers, arguing that it was okay to assume that the same flag value applies to all records on a page. If there are no records in the page, it doesn't matter what you think the flag value is. A potentially stronger complaint is that WAL-reading tools might fail outright on a page with an invalid header, but I'd say that's a robustness issue that they'd need to address anyway. There's never been any guarantee that the trailing pages of a WAL segment are valid. regards, tom lane