Those files correspond to a replication failure. That means the slave thread was not able to apply one transaction. For each of those file, a corresponding warning or error message is present in the mysql error log file.
2019-05-17T13:56:35.525364Z 8 [ERROR] Slave SQL: Error 'Incorrect table definition; there can be only one auto column and it must be defined as a key' on query. Default database: 'percona'. Query: 'CREATE TABLE sbtest100 (
id int(10) unsigned NOT NULL AUTO_INCREMENT,
k int(10) unsigned NOT NULL DEFAULT '0',
c char(120) NOT NULL DEFAULT '',
pad char(60) NOT NULL DEFAULT '',
KEY k_1 (k)
) ENGINE=InnoDB', Error_code: 1075
2019-05-17T13:56:35.525848Z 8 [Warning] WSREP: RBR event 1 Query apply warning: 1, 36304
2019-05-17T13:56:35.571531Z 8 [Warning] WSREP: Ignoring error for TO isolated action: source: b7c194e5-7846-11e9-b6c4-2afd2e47cbf0 version: 4 local: 0 state: APPLYING flags: 65 conn_id: 19 trx_id: -1 seqnos (l: 36935, g: 36304, s: 36303, d: 36303, ts: 60090963212074)
Files are stored on the datadir:
[root@pxc2 mysql]# strings /var/lib/mysql/GRA_8_36304.log
percona
CREATE TABLE sbtest100 (
id int(10) unsigned NOT NULL AUTO_INCREMENT,
k int(10) unsigned NOT NULL DEFAULT '0',
c char(120) NOT NULL DEFAULT '',
pad char(60) NOT NULL DEFAULT '',
KEY k_1 (k)
) ENGINE=InnoDB
https://www.percona.com/blog/2012/12/19/percona-xtradb-cluster-pxc-what-about-gra_-log-files/
Let's create (properly) the table:
CREATE TABLE `sbtest100` (
`id` int(10) unsigned NOT NULL,
`k` int(10) unsigned NOT NULL DEFAULT '0',
`c` char(120) NOT NULL DEFAULT '',
`pad` char(60) NOT NULL DEFAULT '',
KEY `k_1` (`k`)
) ENGINE=InnoDB;
And now let's populate it with 1 single big TRX:
INSERT INTO sbtest100 SELECT * from sbtest1;
The strict mode will prevent to do such a crazy query. Let's override it:
set global pxc_strict_mode='DISABLED'; INSERT INTO sbtest100 SELECT * from sbtest1; set global pxc_strict_mode='ENFORCING';