GRA_*.log
These files contain binlog events in ROW format representing the failed
transaction. That means that the slave thread was not able to apply one of
the transactions. For each of those file, a corresponding warning or error
message is present in the mysql error log file. Those error can also be
false positives like a bad DDL
statement (dropping a table that doesn’t
exists for example) and therefore nothing to worry about. However it’s
always recommended to check these log to understand what’s is happening.
To be able to analyze these files binlog header needs to be added to the log
file. To create the GRA_HEADER
file you need an instance running with
binlog_checksum
set to NONE
and extract first 120 bytes from
the binlog file:
$ head -c 120 mysqld-bin.000001 > GRA_HEADER
$ cat GRA_HEADER > /var/lib/mysql/GRA_1_2-bin.log
$ cat /var/lib/mysql/GRA_1_2.log >> /var/lib/mysql/GRA_1_2-bin.log
$ mysqlbinlog -vvv /var/lib/mysql/GRA_1_2-bin.log
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#160805 9:35:35 server id 1 end_log_pos 120 Start: binlog v 4, server v 5.6.30-76.3-56-log created 160805 9:35:35 at startup
# Warning: this binlog is either in use or was not closed properly.
ROLLBACK/*!*/;
BINLOG '
512kVw8BAAAAdAAAAHgAAAABAAQANS42LjMwLTc2LjMtNTYtbG9nAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAADnXaRXEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAOfS
sRE=
'/*!*/;
# at 120
#160805 9:33:37 server id 0 end_log_pos 79 Query thread_id=27 exec_time=0 error_code=0
use `world`/*!*/;
SET TIMESTAMP=1470389617/*!*/;
SET @@session.pseudo_thread_id=27/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=1073741824/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=8/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
drop table test
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
This information can be used for checking the MySQL error log for the corresponding error message.
160805 9:33:37 8:52:21 [ERROR] Slave SQL: Error 'Unknown table 'test'' on query. Default database: 'test'. Query: 'drop table test', Error_code: 1051
160805 9:33:37 8:52:21 [Warning] WSREP: RBR event 1 Query apply warning: 1, 3
In this example DROP TABLE
statement was executed on a table that doesn’t exist.
galera.cache
This file is used as a main writeset store. It’s implemented as a permanent
ring-buffer file that is preallocated on disk when the node is initialized.
File size can be controlled with the variable gcache.size
. If
this value is bigger, more writesets are cached and chances are better that
the re-joining node will get IST instead of SST. Filename can be changed
with the gcache.name
variable.
grastate.dat
This file contains the Galera state information.
version
- grastate versionuuid
- a unique identifier for the state and the sequence of changes it
undergoes.For more information on how UUID is generated see UUID.seqno
- Ordinal Sequence Number, a 64-bit signed integer used to denote
the position of the change in the sequence. seqno
is 0
when no
writesets have been generated or applied on that node, i.e., not
applied/generated across the lifetime of a grastate
file. -1
is
a special value for the seqno
that is kept in the grastate.dat
while the server is running to allow Galera to distinguish between a clean
and an unclean shutdown. Upon a clean shutdown, the correct seqno
value
is written to the file. So, when the server is brought back up, if the
value is still -1
, this means that the server did not shut down
cleanly. If the value is greater than 0
, this means that the shutdown
was clean. -1
is then written again to the file in order to allow the
server to correctly detect if the next shutdown was clean in the same
manner.cert_index
- cert index restore through grastate is not implemented yetExamples of this file look like this:
In case server node has this state when not running it means that that node crashed during the transaction processing.
# GALERA saved state
version: 2.1
uuid: 1917033b-7081-11e2-0800-707f5d3b106b
seqno: -1
cert_index:
In case server node has this state when not running it means that the node was gracefully shut down.
# GALERA saved state
version: 2.1
uuid: 1917033b-7081-11e2-0800-707f5d3b106b
seqno: 5192193423942
cert_index:
In case server node has this state when not running it means that the node crashed during the DDL.
# GALERA saved state
version: 2.1
uuid: 00000000-0000-0000-0000-000000000000
seqno: -1
cert_index:
gvwstate.dat
This file is used for Primary Component recovery feature. This file is
created once primary component is formed or changed, so you can get the
latest primary component this node was in. And this file is deleted when the
node is shutdown gracefully.
First part contains the node UUID information. Second part contains
the view information. View information is written between #vwbeg
and
#vwend
. View information consists of:
view_id: [view_type] [view_uuid] [view_seq]. -
view_type
is always3
which means primary view.view_uuid
andview_seq
identifies a unique view, which could be perceived as identifier of this primary component.bootstrap: [bootstarp_or_not]. - It could be
0
or1
, but it does not affect primary component recovery process now.member: [node’s uuid] [node’s segment]. - it represents all nodes in this primary component.
Example of this file looks like this:
my_uuid: c5d5d990-30ee-11e4-aab1-46d0ed84b408 #vwbeg view_id: 3 bc85bd53-31ac-11e4-9895-1f2ce13f2542 2 bootstrap: 0 member: bc85bd53-31ac-11e4-9895-1f2ce13f2542 0 member: c5d5d990-30ee-11e4-aab1-46d0ed84b408 0 #vwend
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