MDEV#6316: Fix mysqldump SST method to transfer binlog

state to the joiner

In mysqldump SST, if Galera nodes are started with --log-bin and
-log-slave-updates, the GTID sequence increases as the dump is
played on the joiner, leaving behind the donor.

This patch introduces a new mysqldump option --galera-sst-mode,
which if enabled, would

a) Add command to set off binary logging (log_bin=OFF).
b) Add command to set @@global.gtid_binlog_state to that
   of donor.

This will help in keeping the GTIDs consistent post-SST across
the nodes.

2 files changed, 58 insertions, 0 deletions

diff --git a/client/client_priv.h b/client/client_priv.h
index 656c8fcf32a..dddf934e509 100644
--- a/client/client_priv.h
+++ b/client/client_priv.h
@@ -92,6 +92,9 @@ enum options_client
   OPT_REPORT_PROGRESS,
   OPT_SKIP_ANNOTATE_ROWS_EVENTS,
   OPT_SSL_CRL, OPT_SSL_CRLPATH,
+#ifdef WITH_WSREP
+  OPT_GALERA_SST_MODE,
+#endif
   OPT_MAX_CLIENT_OPTION /* should be always the last */
 };
 
diff --git a/client/mysqldump.c b/client/mysqldump.c
index cb4fa022d4f..5963d4da460 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -111,6 +111,9 @@ static my_bool  verbose= 0, opt_no_create_info= 0, opt_no_data= 0,
                 opt_slave_apply= 0, 
                 opt_include_master_host_port= 0,
                 opt_events= 0, opt_comments_used= 0,
+#ifdef WITH_WSREP
+                opt_galera_sst_mode= 0,
+#endif
                 opt_alltspcs=0, opt_notspcs= 0;
 static my_bool insert_pat_inited= 0, debug_info_flag= 0, debug_check_flag= 0;
 static ulong opt_max_allowed_packet, opt_net_buffer_length;
@@ -346,6 +349,14 @@ static struct my_option my_long_options[] =
   {"force", 'f', "Continue even if we get an SQL error.",
    &ignore_errors, &ignore_errors, 0, GET_BOOL, NO_ARG,
    0, 0, 0, 0, 0, 0},
+#ifdef WITH_WSREP
+  {"galera-sst-mode", OPT_GALERA_SST_MODE, "This mode is normally used "
+   "in mysqldump snapshot-state transfer in a Galera cluster. If enabled, "
+   "mysqldump additionally emits statements to turn off binary logging and "
+   "set global gtid_binlog_state with the current value.",
+   &opt_galera_sst_mode, &opt_galera_sst_mode, 0, GET_BOOL, NO_ARG, 0, 0, 0,
+   0, 0, 0},
+#endif
   {"help", '?', "Display this help message and exit.", 0, 0, 0, GET_NO_ARG,
    NO_ARG, 0, 0, 0, 0, 0, 0},
   {"hex-blob", OPT_HEXBLOB, "Dump binary strings (BINARY, "
@@ -4799,6 +4810,44 @@ static int dump_selected_tables(char *db, char **table_names, int tables)
 } /* dump_selected_tables */
 
 
+#ifdef WITH_WSREP
+/**
+  Additionally emit the following statements :
+  a) SET @@session.sql_log_bin=OFF;
+  b) SET @@global.gtid_binlog_state='[N-N-N,...]'
+*/
+static int wsrep_add_sst_mode_cmds(MYSQL *mysql) {
+  MYSQL_RES *res;
+  MYSQL_ROW row;
+
+  if (mysql_get_server_version(mysql) < 100005) {
+    // @@gtid_binlog_state does not exist.
+    return 0;
+  }
+
+  if (mysql_query_with_error_report(mysql, &res, "SELECT "
+                                    "@@global.gtid_binlog_state"))
+    return 1;
+
+  if (mysql_num_rows(res) != 1)
+    // No entry for @@global.gtid_binlog_state, nothing needs to be done.
+    return 0;
+
+  if (!(row= mysql_fetch_row(res)) || !(char *)row[0])
+    return 1;
+
+  // first, add a command to turn off binary logging,
+  fprintf(md_result_file, "SET @@session.sql_log_bin=OFF;\n");
+
+  // followed by, a command to set global gtid_binlog_state.
+  fprintf(md_result_file, "SET @@global.gtid_binlog_state='%s';\n",
+          (char*)row[0]);
+
+  mysql_free_result(res);
+  return 0;
+}
+#endif
+
 static int do_show_master_status(MYSQL *mysql_con, int consistent_binlog_pos)
 {
   MYSQL_ROW row;
@@ -5743,6 +5792,12 @@ int main(int argc, char **argv)
   /* Add 'STOP SLAVE to beginning of dump */
   if (opt_slave_apply && add_stop_slave())
     goto err;
+
+#ifdef WITH_WSREP
+  if (opt_galera_sst_mode && wsrep_add_sst_mode_cmds(mysql))
+    goto err;
+#endif
+
   if (opt_master_data && do_show_master_status(mysql, consistent_binlog_pos))
     goto err;
   if (opt_slave_data && do_show_slave_status(mysql))