pg_waldump --help claims that you run it like this: Usage: pg_waldump [OPTION]... [STARTSEG [ENDSEG]]
And https://www.postgresql.org/docs/10/static/pgwaldump.html agrees. Since square brackets indicate optional arguments, this sort of makes it sound like running pg_waldump with no arguments ought to work. But it doesn't: $ pg_waldump pg_waldump: no arguments specified Try "pg_waldump --help" for more information. If we removed the error check that displays "pg_waldump: no arguments specified", then it would still fail, but with a more useful error message: $ pg_waldump -- pg_waldump: no start WAL location given Try "pg_waldump --help" for more information. That message ought to perhaps be changed to say that you specified neither the start WAL location nor the start WAL file, but even as it stands it's certainly better than "no arguments specified". Another problem is that if the file name you pass to pg_waldump doesn't happen to have a name that looks like a WAL file, it fails in a completely ridiculous fashion: $ pg_waldump /etc/passwd pg_waldump: FATAL: could not find file "000000017C55C16F000000FF": No such file or directory The problem appears to be that fuzzy_open_file() successfully opens the file and then invokes XLogFromFileName() on the filename. XLogFromFileName() calls sscanf() on the file name without any error checking, which I think results in leaving private.timeline uninitialized and setting segno to whatever preexisting garbage was in the log and segno variables declared inside XLogFromFileName(), resulting in an attempt to find a more or less completely random file. A slightly broader concern is whether we need to require the start position at all. It seems like one could locate the WAL directory using the existing logic, then search for the earliest file. It might be a little unclear what "earliest" means when multiple timelines are present, but I bet we could come up with some behavior that would be convenient for most users. It would be quite handy to be able to run this without arguments (or just with -z) and have it process all the WAL files that you've got on hand. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers