If you see like 

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130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate column name 'File_priv'' on query. Default database: 'mysql'. Query: 'ALTER TABLE user add File_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL', Error_code: 1060
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 532
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 55, g: 532, s: 531, d: 531, ts: 1379270745278593506)
130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate column name 'Grant_priv'' on query. Default database: 'mysql'. Query: 'ALTER TABLE user add Grant_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add References_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Index_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Alter_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL', Error_code: 1060
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 533
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 56, g: 533, s: 532, d: 532, ts: 1379270745289432756)
130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate column name 'Grant_priv'' on query. Default database: 'mysql'. Query: 'ALTER TABLE host add Grant_priv enum('N','Y') NOT NULL,add References_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Index_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Alter_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL', Error_code: 1060
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 534
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 57, g: 534, s: 533, d: 533, ts: 1379270745291123713)
130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate column name 'Grant_priv'' on query. Default database: 'mysql'. Query: 'ALTER TABLE db add Grant_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add References_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Index_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL,add Alter_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL', Error_code: 1060
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 535
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 58, g: 535, s: 534, d: 534, ts: 1379270745292659319)
130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate column name 'ssl_type'' on query. Default database: 'mysql'. Query: 'ALTER TABLE user
 ADD ssl_type enum('','ANY','X509', 'SPECIFIED') COLLATE utf8_general_ci NOT NULL,
 ADD ssl_cipher BLOB NOT NULL,
 ADD x509_issuer BLOB NOT NULL,
 ADD x509_subject BLOB NOT NULL', Error_code: 1060
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 536
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 59, g: 536, s: 535, d: 535, ts: 1379270745296376534)
130916  0:15:45 [ERROR] Slave SQL: Error 'Duplicate key name 'Grantor'' on query. Default database: 'mysql'. Query: 'ALTER TABLE tables_priv
   ADD KEY Grantor (Grantor)', Error_code: 1061
130916  0:15:45 [Warning] WSREP: RBR event 1 Query apply warning: 1, 538
130916  0:15:45 [Warning] WSREP: Ignoring error for TO isolated action: source: ecbbe2eb-1e36-11e3-a81b-a63f18512e2e version: 2 local: 0 state: APPLYING flags: 65 conn_id: 9 trx_id: -1 seqnos (l: 61, g: 538, s: 537, d: 537, ts: 1379270745313530556)
====================================================

in the log when a new node has been added, this is from debian-start.


The workaround is to do  'touch /etc/mysql/NO-DEBIAN-START'. This will skip it.  Probably it should be default and be reversed.  This will be checked in future.  
I will keep this issue open till then.

Hence, it is highly recommended to  touch those files.


This is not related to any foreign key issue.