Remove useless lstat() call in pg_rewind.

This is duplicative of an lstat that was just done by the calling
function (traverse_datadir), besides which we weren't really doing
anything with the results.  There's not much point in checking to
see if someone removed the file since the previous lstat, since the
FILE_ACTION_REMOVE code would have to deal with missing-file cases
anyway.  Moreover, the "exists = false" assignment was a dead store;
nothing was done with that value later.

A syscall saved is a syscall earned, so back-patch to 9.5
where this code was introduced.

Discussion: https://postgr.es/m/1221796.1599329320@sss.pgh.pa.us

diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c
index 1879257b66a378bf3913f7821fbada5d8ee0276f..1abc257177efdb42afbfe8ba07a7b70b77de9353 100644 (file)
--- a/src/bin/pg_rewind/filemap.c
+++ b/src/bin/pg_rewind/filemap.c
@@ -349,8 +349,6 @@ process_target_file(const char *path, file_type_t type, size_t oldsize,
                                        const char *link_target)
 {
        bool            exists;
-       char            localpath[MAXPGPATH];
-       struct stat statbuf;
        file_entry_t key;
        file_entry_t *key_ptr;
        filemap_t  *map = filemap;
@@ -362,16 +360,6 @@ process_target_file(const char *path, file_type_t type, size_t oldsize,
         * the source data folder when processing the source files.
         */
 
-       snprintf(localpath, sizeof(localpath), "%s/%s", datadir_target, path);
-       if (lstat(localpath, &statbuf) < 0)
-       {
-               if (errno != ENOENT)
-                       pg_fatal("could not stat file \"%s\": %m",
-                                        localpath);
-
-               exists = false;
-       }
-
        if (map->array == NULL)
        {
                /* on first call, initialize lookup array */