我正在处理cannot write to log...错误（在link中描述），这是在Windows操作系统上升级PostgreSQL期间发生的。这些答案都没有帮助我。在调试此问题时，我注意到升级成功后，pg_upgrade_internal.log中的日志显示如下：
Running in verbose mode
-----------------------------------------------------------------
pg_upgrade run on Mon Nov 27 10:03:23 2017
-----------------------------------------------------------------
Running in verbose mode
-----------------------------------------------------------------
pg_upgrade run on Mon Nov 27 10:03:23 2017
-----------------------------------------------------------------
Performing Consistency Checks
-----------------------------
....
如果您发现，Running in .. pg_upgrade run...出现了两次。所以，我试着查看PostgreSQL 9.5.2的源代码。这些日志似乎是从文件void parseCommandLine(int argc, char *argv[])（link）的函数\src\bin\pg_upgrade\option.c中编写的。以下是PostgreSQL 9.5.2的源代码：
/*
* parseCommandLine()
*
* Parses the command line (argc, argv[]) and loads structures
*/
void
parseCommandLine(int argc, char *argv[])
{
static struct option long_options[] = {
{"old-datadir", required_argument, NULL, 'd'},
{"new-datadir", required_argument, NULL, 'D'},
{"old-bindir", required_argument, NULL, 'b'},
{"new-bindir", required_argument, NULL, 'B'},
{"old-options", required_argument, NULL, 'o'},
{"new-options", required_argument, NULL, 'O'},
{"old-port", required_argument, NULL, 'p'},
{"new-port", required_argument, NULL, 'P'},
{"username", required_argument, NULL, 'U'},
{"check", no_argument, NULL, 'c'},
{"link", no_argument, NULL, 'k'},
{"retain", no_argument, NULL, 'r'},
{"jobs", required_argument, NULL, 'j'},
{"verbose", no_argument, NULL, 'v'},
{NULL, 0, NULL, 0}
};
int option; /* Command line option */
int optindex = 0; /* used by getopt_long */
int os_user_effective_id;
FILE *fp;
char **filename;
time_t run_time = time(NULL);
user_opts.transfer_mode = TRANSFER_MODE_COPY;
os_info.progname = get_progname(argv[0]);
/* Process libpq env. variables; load values here for usage() output */
old_cluster.port = getenv("PGPORTOLD") ? atoi(getenv("PGPORTOLD")) : DEF_PGUPORT;
new_cluster.port = getenv("PGPORTNEW") ? atoi(getenv("PGPORTNEW")) : DEF_PGUPORT;
os_user_effective_id = get_user_info(&os_info.user);
/* we override just the database user name; we got the OS id above */
if (getenv("PGUSER"))
{
pg_free(os_info.user);
/* must save value, getenv()'s pointer is not stable */
os_info.user = pg_strdup(getenv("PGUSER"));
}
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
usage();
exit(0);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
puts("pg_upgrade (PostgreSQL) " PG_VERSION);
exit(0);
}
}
/* Allow help and version to be run as root, so do the test here. */
if (os_user_effective_id == 0)
pg_fatal("%s: cannot be run as root\n", os_info.progname);
if ((log_opts.internal = fopen_priv(INTERNAL_LOG_FILE, "a")) == NULL)
pg_fatal("cannot write to log file %s\n", INTERNAL_LOG_FILE);
while ((option = getopt_long(argc, argv, "d:D:b:B:cj:ko:O:p:P:rU:v",
long_options, &optindex)) != -1)
{
switch (option)
{
case 'b':
old_cluster.bindir = pg_strdup(optarg);
break;
case 'B':
new_cluster.bindir = pg_strdup(optarg);
break;
case 'c':
user_opts.check = true;
break;
case 'd':
old_cluster.pgdata = pg_strdup(optarg);
old_cluster.pgconfig = pg_strdup(optarg);
break;
case 'D':
new_cluster.pgdata = pg_strdup(optarg);
new_cluster.pgconfig = pg_strdup(optarg);
break;
case 'j':
user_opts.jobs = atoi(optarg);
break;
case 'k':
user_opts.transfer_mode = TRANSFER_MODE_LINK;
break;
case 'o':
/* append option? */
if (!old_cluster.pgopts)
old_cluster.pgopts = pg_strdup(optarg);
else
{
char *old_pgopts = old_cluster.pgopts;
old_cluster.pgopts = psprintf("%s %s", old_pgopts, optarg);
free(old_pgopts);
}
break;
case 'O':
/* append option? */
if (!new_cluster.pgopts)
new_cluster.pgopts = pg_strdup(optarg);
else
{
char *new_pgopts = new_cluster.pgopts;
new_cluster.pgopts = psprintf("%s %s", new_pgopts, optarg);
free(new_pgopts);
}
break;
/*
* Someday, the port number option could be removed and passed
* using -o/-O, but that requires postmaster -C to be
* supported on all old/new versions (added in PG 9.2).
*/
case 'p':
if ((old_cluster.port = atoi(optarg)) <= 0)
{
pg_fatal("invalid old port number\n");
exit(1);
}
break;
case 'P':
if ((new_cluster.port = atoi(optarg)) <= 0)
{
pg_fatal("invalid new port number\n");
exit(1);
}
break;
case 'r':
log_opts.retain = true;
break;
case 'U':
pg_free(os_info.user);
os_info.user = pg_strdup(optarg);
os_info.user_specified = true;
/*
* Push the user name into the environment so pre-9.1
* pg_ctl/libpq uses it.
*/
pg_putenv("PGUSER", os_info.user);
break;
case 'v':
pg_log(PG_REPORT, "Running in verbose mode\n");
log_opts.verbose = true;
break;
default:
pg_fatal("Try \"%s --help\" for more information.\n",
os_info.progname);
break;
}
}
/* label start of upgrade in logfiles */
for (filename = output_files; *filename != NULL; filename++)
{
if ((fp = fopen_priv(*filename, "a")) == NULL)
pg_fatal("cannot write to log file %s\n", *filename);
/* Start with newline because we might be appending to a file. */
fprintf(fp, "\n"
"-----------------------------------------------------------------\n"
" pg_upgrade run on %s"
"-----------------------------------------------------------------\n\n",
ctime(&run_time));
fclose(fp);
}
/* Turn off read-only mode; add prefix to PGOPTIONS? */
if (getenv("PGOPTIONS"))
{
char *pgoptions = psprintf("%s %s", FIX_DEFAULT_READ_ONLY,
getenv("PGOPTIONS"));
pg_putenv("PGOPTIONS", pgoptions);
pfree(pgoptions);
}
else
pg_putenv("PGOPTIONS", FIX_DEFAULT_READ_ONLY);
/* Get values from env if not already set */
check_required_directory(&old_cluster.bindir, NULL, "PGBINOLD", "-b",
"old cluster binaries reside");
check_required_directory(&new_cluster.bindir, NULL, "PGBINNEW", "-B",
"new cluster binaries reside");
check_required_directory(&old_cluster.pgdata, &old_cluster.pgconfig,
"PGDATAOLD", "-d", "old cluster data resides");
check_required_directory(&new_cluster.pgdata, &new_cluster.pgconfig,
"PGDATANEW", "-D", "new cluster data resides");
#ifdef WIN32
/*
* On Windows, initdb --sync-only will fail with a "Permission denied"
* error on file pg_upgrade_utility.log if pg_upgrade is run inside the
* new cluster directory, so we do a check here.
*/
{
char cwd[MAXPGPATH],
new_cluster_pgdata[MAXPGPATH];
strlcpy(new_cluster_pgdata, new_cluster.pgdata, MAXPGPATH);
canonicalize_path(new_cluster_pgdata);
if (!getcwd(cwd, MAXPGPATH))
pg_fatal("cannot find current directory\n");
canonicalize_path(cwd);
if (path_is_prefix_of_path(new_cluster_pgdata, cwd))
pg_fatal("cannot run pg_upgrade from inside the new cluster data directory on Windows\n");
}
#endif
}
此函数parseCommandLine仅调用一次，如下面的代码所示：
int
main(int argc, char **argv)
{
char *analyze_script_file_name = NULL;
char *deletion_script_file_name = NULL;
bool live_check = false;
parseCommandLine(argc, argv);
get_restricted_token(os_info.progname);
...
return 0;
}
任何人都可以解释一下，这是怎么回事？为什么日志出现两次？我可能会遗漏一些非常明显的东西。
更新
其他文件pg_upgrade_server_start.log，pg_upgrade_server.log，pg_upgrade_utility.log也包含重复日志，如下所述：
-----------------------------------------------------------------
pg_upgrade run on Mon Nov 27 10:03:23 2017
-----------------------------------------------------------------
-----------------------------------------------------------------
pg_upgrade run on Mon Nov 27 10:03:23 2017
-----------------------------------------------------------------