pg_upgrade: remove pg_multixact files left by initdb

This fixes a bug that caused vacuum to fail when the '0000' files left
by initdb were accessed as part of vacuum's cleanup of old pg_multixact
files.

Backpatch through 9.3

diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
index 773bb07e04eb9c2a3384ff68fc9398fe5cbd7313..c7386cdd3d3bc74b60fb57fb5cd0f6353988c10a 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.c
+++ b/contrib/pg_upgrade/pg_upgrade.c
@@ -363,22 +363,35 @@ create_new_objects(void)
 }
 
 /*
- * Delete the given subdirectory contents from the new cluster, and copy the
- * files from the old cluster into it.
+ * Delete the given subdirectory contents from the new cluster
  */
 static void
-copy_subdir_files(char *subdir)
+remove_new_subdir(char *subdir, bool rmtopdir)
 {
-   char        old_path[MAXPGPATH];
    char        new_path[MAXPGPATH];
 
    prep_status("Deleting files from new %s", subdir);
 
-   snprintf(old_path, sizeof(old_path), "%s/%s", old_cluster.pgdata, subdir);
    snprintf(new_path, sizeof(new_path), "%s/%s", new_cluster.pgdata, subdir);
-   if (!rmtree(new_path, true))
+   if (!rmtree(new_path, rmtopdir))
        pg_fatal("could not delete directory \"%s\"\n", new_path);
+
    check_ok();
+}
+
+/*
+ * Copy the files from the old cluster into it
+ */
+static void
+copy_subdir_files(char *subdir)
+{
+   char        old_path[MAXPGPATH];
+   char        new_path[MAXPGPATH];
+
+   remove_new_subdir(subdir, true);
+
+   snprintf(old_path, sizeof(old_path), "%s/%s", old_cluster.pgdata, subdir);
+   snprintf(new_path, sizeof(new_path), "%s/%s", new_cluster.pgdata, subdir);
 
    prep_status("Copying old %s to new server", subdir);
 
@@ -419,6 +432,7 @@ copy_clog_xlog_xid(void)
    {
        copy_subdir_files("pg_multixact/offsets");
        copy_subdir_files("pg_multixact/members");
+
        prep_status("Setting next multixact ID and offset for new cluster");
 
        /*
@@ -436,6 +450,13 @@ copy_clog_xlog_xid(void)
    }
    else if (new_cluster.controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER)
    {
+       /*
+        * Remove files created by initdb that no longer match the
+        * new multi-xid value.
+        */
+       remove_new_subdir("pg_multixact/offsets", false);
+       remove_new_subdir("pg_multixact/members", false);
+
        prep_status("Setting oldest multixact ID on new cluster");
 
        /*