On Sun, Mar 29, 2020 at 01:22:04PM -0400, Tom Lane wrote: > Justin Pryzby <pry...@telsasoft.com> writes: > > On Sun, Mar 29, 2020 at 12:37:05PM -0400, Tom Lane wrote: > >> After looking at the callers of pg_ls_dir_files, and noticing that > >> it's already defined to ignore anything that's not a regular file, > >> I think switching to lstat makes sense. > > > Yea, only pg_ls_dir() shows special file types (and currently the others > > even > > hide dirs). > > > The essence of your patch is to ignore ENOENT, but you also changed to use > > lstat(), which seems unrelated. That means we'll now hide (non-broken) > > symlinks. Is that intentional/needed ? > > Well, the following comment says "ignore anything but regular files", > so I'm supposing that that is the behavior that we actually want here > and failed to implement correctly. There might be scope for > additional directory-reading functions, but I'd think you'd want > more information (such as the file type) returned from anything > that doesn't act this way.
Maybe pg_stat_file() deserves similar attention ? Right now, it'll fail on a broken link. If we changed it to lstat(), then it'd work, but it'd also show metadata for the *link* rather than its target. Patch proposed as v14-0001 patch here may be relevant: https://www.postgresql.org/message-id/20200317190401.GY26184%40telsasoft.com - indicating if it is a directory. Typical usages include: + indicating if it is a directory (or a symbolic link to a directory). ... > In practice, since these directories shouldn't contain symlinks, > it's likely moot. The only place in PG data directories where > we actually expect symlinks is pg_tablespace ... and that contains > symlinks to directories, so that this function would ignore them > anyway. I wouldn't hesitate to make symlinks, at least in log. It's surprising when files are hidden, but I won't argue about the best behavior here. I'm thinking of distributions or local configurations that use /var/log/postgresql. I didn't remember or didn't realize, but it looks like debian's packages use logging_collector=off and then launch postmaster with 2> /var/log/postgres/... It seems reasonable to do something like: log/huge-querylog.csv => /zfs/compressed/... -- Justin