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Preserver failover slots when cloning a standby, if enabled

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This commit is contained in:
Ian Barwick
2016-04-05 16:47:47 +09:00
parent 3f0d1754a4
commit d48093e732
2 changed files with 70 additions and 44 deletions
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113
repmgr.c
View File

@@ -121,7 +121,7 @@ static bool remote_command(const char *host, const char *user, const char *comma
static void format_db_cli_params(const char *conninfo, char *output);
static bool copy_file(const char *old_filename, const char *new_filename);
static void read_backup_label(const char *local_data_directory, struct BackupLabel *backup_label);
static void read_backup_label(const char *local_data_directory, struct BackupLabel *out_backup_label);
/* Global variables */
static const char *keywords[6];
@@ -144,12 +144,11 @@ static char repmgr_slot_name[MAXLEN] = "";
static char *repmgr_slot_name_ptr = NULL;
static char path_buf[MAXLEN] = "";
static struct BackupLabel backup_label;
/* Collate command line errors and warnings here for friendlier reporting */
ErrorList cli_errors = { NULL, NULL };
ErrorList cli_warnings = { NULL, NULL };
static struct BackupLabel backup_label;
int
main(int argc, char **argv)
@@ -1333,6 +1332,7 @@ do_standby_clone(void)
PQExpBufferData event_details;
/*
* If dest_dir (-D/--pgdata) was provided, this will become the new data
* directory (otherwise repmgr will default to the same directory as on the
@@ -1664,6 +1664,12 @@ do_standby_clone(void)
goto stop_backup;
}
/* Read backup label copied from primary */
/* XXX ensure this function does not exit on error as we'd need to stop the backup */
read_backup_label(local_data_directory, &backup_label);
printf("Label: %s; file: %s\n", backup_label.label, backup_label.start_wal_file);
/* Handle tablespaces */
sqlquery_snprintf(sqlquery,
@@ -1955,35 +1961,38 @@ stop_backup:
exit(retval);
}
read_backup_label(local_data_directory, &backup_label);
/*
* Clean up any $PGDATA subdirectories which may contain
* files which won't be removed by rsync and which could
* be stale or are otherwise not required
*/
if (runtime_options.rsync_only && runtime_options.force)
if (runtime_options.rsync_only)
{
char script[MAXLEN];
char label_path[MAXPGPATH];
/*
* Remove any existing WAL from the target directory, since
* rsync's --exclude option doesn't do it.
*/
maxlen_snprintf(script, "rm -rf %s/pg_xlog/*",
local_data_directory);
r = system(script);
if (r != 0)
if (runtime_options.force)
{
log_err(_("unable to empty local WAL directory %s/pg_xlog/\n"),
local_data_directory);
exit(ERR_BAD_RSYNC);
/*
* Remove any existing WAL from the target directory, since
* rsync's --exclude option doesn't do it.
*/
maxlen_snprintf(script, "rm -rf %s/pg_xlog/*",
local_data_directory);
r = system(script);
if (r != 0)
{
log_err(_("unable to empty local WAL directory %s/pg_xlog/\n"),
local_data_directory);
exit(ERR_BAD_RSYNC);
}
}
/*
* Remove any replication slot directories; this matches the
* behaviour a base backup, which would result in an empty
* pg_replslot directory.
* Remove any existing replication slot directories from previous use
* of this data directory; this matches the behaviour of a fresh
* pg_basebackup, which would usually result in an empty pg_replslot
* directory.
*
* If the backup label contains a nonzero
* 'MIN FAILOVER SLOT LSN' entry we retain the slots and let
@@ -1999,6 +2008,8 @@ stop_backup:
{
maxlen_snprintf(script, "rm -rf %s/pg_replslot/*",
local_data_directory);
log_debug("deleting pg_replslot directory contents\n");
r = system(script);
if (r != 0)
{
@@ -2007,6 +2018,13 @@ stop_backup:
exit(ERR_BAD_RSYNC);
}
}
/* delete the backup label file copied from the primary */
maxlen_snprintf(label_path, "%s/backup_label", local_data_directory);
if (0 && unlink(label_path) < 0 && errno != ENOENT)
{
log_warning(_("unable to delete backup label file %s\n"), label_path);
}
}
/* Finally, write the recovery.conf file */
@@ -2123,7 +2141,7 @@ parse_label_lsn(const char *label_key, const char *label_value)
/*======================================
* Read entries of interest from the backup label.
*
* Sample backup label:
* Sample backup label (with failover slots):
*
* START WAL LOCATION: 0/6000028 (file 000000010000000000000006)
* CHECKPOINT LOCATION: 0/6000060
@@ -2141,10 +2159,11 @@ read_backup_label(const char *local_data_directory, struct BackupLabel *out_back
char label_path[MAXPGPATH];
FILE *label_file;
int nmatches = 0;
char label_key[MAXLEN];
char label_value[MAXLEN];
char line[MAXLEN];
out_backup_label->start_wal_location = InvalidXLogRecPtr;
out_backup_label->start_wal_file[0] = '\0';
out_backup_label->checkpoint_location = InvalidXLogRecPtr;
out_backup_label->backup_from[0] = '\0';
out_backup_label->backup_method[0] = '\0';
@@ -2157,43 +2176,52 @@ read_backup_label(const char *local_data_directory, struct BackupLabel *out_back
label_file = fopen(label_path, "r");
if (label_file == NULL)
{
log_err(_("could not open backup label file %s: %s"),
log_err(_("read_backup_label: could not open backup label file %s: %s"),
label_path, strerror(errno));
exit(ERR_BAD_BACKUP_LABEL);
}
log_info(_("standby clone: backup label file '%s'\n"),
log_info(_("read_backup_label: parsing backup label file '%s'\n"),
label_path);
do
while(fgets(line, sizeof line, label_file) != NULL)
{
char label_key[MAXLEN];
char label_value[MAXLEN];
char newline;
/*
* Scan a line, including newline char.
*
* See http://stackoverflow.com/a/8097776/398670
*/
nmatches = fscanf(label_file, "%" MAXLEN_STR "s: %" MAXLEN_STR "[^\n]%c",
&label_key[0], &label_value[0], &newline);
nmatches = sscanf(line, "%" MAXLEN_STR "[^:]: %" MAXLEN_STR "[^\n]%c",
label_key, label_value, &newline);
if (nmatches != 3)
break;
if (newline != '\n')
{
log_err(_("standby clone: line too long in backup label file. Line begins \"%s: %s\""),
log_err(_("read_backup_label: line too long in backup label file. Line begins \"%s: %s\""),
label_key, label_value);
exit(ERR_BAD_BACKUP_LABEL);
}
log_debug("standby clone: got backup label entry \"%s: %s\"",
log_debug("standby clone: got backup label entry \"%s: %s\"\n",
label_key, label_value);
if (strcmp(label_key, "START WAL LOCATION") == 0)
{
char start_wal_location[MAXLEN];
char wal_filename[MAXLEN];
nmatches = sscanf(label_value, "%" MAXLEN_STR "s (file %" MAXLEN_STR "[^)]", start_wal_location, wal_filename);
if (nmatches != 2)
{
log_err(_("read_backup_label: unable to parse \"START WAL LOCATION\" in backup label\n"));
exit(ERR_BAD_BACKUP_LABEL);
}
out_backup_label->start_wal_location =
parse_label_lsn(&label_key[0], &label_value[0]);
parse_label_lsn(&label_key[0], start_wal_location);
(void) strncpy(out_backup_label->start_wal_file, wal_filename, MAXLEN);
out_backup_label->start_wal_file[MAXLEN-1] = '\0';
}
else if (strcmp(label_key, "CHECKPOINT LOCATION") == 0)
{
@@ -2227,11 +2255,10 @@ read_backup_label(const char *local_data_directory, struct BackupLabel *out_back
}
else
{
log_info("standby clone: ignored unrecognised backup label entry \"%s: %s\"",
log_info("read_backup_label: ignored unrecognised backup label entry \"%s: %s\"",
label_key, label_value);
}
}
while (!feof(label_file));
(void) fclose(label_file);
}
@@ -4224,6 +4251,7 @@ test_ssh_connection(char *host, char *remote_user)
return r;
}
static int
copy_remote_files(char *host, char *remote_user, char *remote_path,
char *local_path, bool is_directory, int server_version_num)
@@ -4268,6 +4296,9 @@ copy_remote_files(char *host, char *remote_user, char *remote_path,
* See function 'sendDir()' in 'src/backend/replication/basebackup.c' -
* we're basically simulating what pg_basebackup does, but with rsync rather
* than the BASEBACKUP replication protocol command.
*
* *However* currently we'll always copy the contents of the 'pg_replslot'
* directory and delete later if appropriate.
*/
if (is_directory)
{
@@ -4296,12 +4327,6 @@ copy_remote_files(char *host, char *remote_user, char *remote_path,
appendPQExpBuffer(&rsync_flags, "%s",
" --exclude=pg_xlog/* --exclude=pg_log/* --exclude=pg_stat_tmp/*");
if (server_version_num >= 90400)
{
appendPQExpBuffer(&rsync_flags, "%s",
" --exclude=pg_replslot/*");
}
maxlen_snprintf(script, "rsync %s %s:%s/* %s",
rsync_flags.data, host_string, remote_path, local_path);
}

1
repmgr.h
View File

@@ -100,6 +100,7 @@ typedef struct
struct BackupLabel
{
XLogRecPtr start_wal_location;
char start_wal_file[MAXLEN];
XLogRecPtr checkpoint_location;
char backup_from[MAXLEN];
char backup_method[MAXLEN];