Replace wsrep_causal_reads with wsrep_sync_wait

[Raghavendra D Prabhu]

Currently innobackupex sets session wsrep_causal_reads to OFF to gather status while FTWRL is in progress. Since wsrep_causal_reads is deprecated, wsrep_sync_wait needs to be used.

Details here https://www.percona.com/doc/percona-xtradb-cluster/5.5/wsrep-system-index.html#wsrep_sync_wait

[Nilnandan Joshi (nilnandan-joshi)]

Confirmed.

nilnandan@desktop:~$ xtrabackup --version
xtrabackup version 2.2.11 based on MySQL server 5.6.24 Linux (x86_64) (revision id: )
nilnandan@desktop:~$

nilnandan@desktop:~$ head -3543 /usr/bin/innobackupex | tail -12

    if ($have_galera_enabled) {
        mysql_query($con, "SET SESSION wsrep_causal_reads=0");
    }

    mysql_query($con, "FLUSH TABLES WITH READ LOCK");

    $now = current_time();
    print STDERR "$now $prefix All tables locked and flushed to disk\n";

    # stop query killer process
    if ($option_kill_long_queries_timeout) {
nilnandan@desktop:~$
nilnandan@desktop:~$
nilnandan@desktop:~$

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-1331