MySQL Bugs: #66184: mysqldump: Got an error writing communication packets, Error

Bug #66184	mysqldump: Got an error writing communication packets, Error_code: 1160
Submitted:	3 Aug 2012 12:33	Modified:	16 Dec 2014 21:29
Reporter:	K Vargo	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: mysqldump Command-line Client	Severity:	S2 (Serious)
Version:	5.1.62, 5.5.25a	OS:	Linux (RHEL-5.x)
Assigned to:	Assigned Account	CPU Architecture:	Any
Tags:	1160

Description:
Much like behavior described in: http://bugs.mysql.com/bug.php?id=51196
we see intermittent failure of `mysqldump' with error 1160.  One or more database from our database server will fail to properly export.  FEDERATED engine is ON in the database.  However, while this may be, but more often is not the databases that include FEDERATED tables.
Sometimes running the mysqldump in a loop allows a successful backup to be taken, simple retry behavior.  mysqldump is configured to use SOCKETS.
E.g.,
MYSQL_SOCKET='/var/lib/mysql/mysql.sock'
NUMBER_RETRY=6
mysqldump -u root -p"${MYSQL_PASS}" --debug-check --debug-info --protocol=SOCKET --socket=$MYSQL_SOCKET --single-transaction --max_allowed_packet=1GB --verbose --log-error=${MYSQL_LOG}.${BACKUP_RETRY} --routines ${database_name} 
the debug logs provide no additional useful information.

How to repeat:
Intermittent, not directly reproducable.  We have a cron for various times in the evening that takes backups, from 22:00 to 00:00.  Typically the problem will show on one server for weeks, and then disappear, only to show up on a different server.
The principally affected servers are VMs, which may/not contribute.

Suggested fix:
* Review changes in bug #51196 and see if there might be a second instance of the issue in mysqldump or related portions of the code (i.e., missed-a-case of fix for #51196).
* Add additional debugging information to help pinpoint the underlying case of the 1160 failure.

Strace capture appears to show the dump running until it starts hitting timeouts, and then gives up:

--
mysql-backup-dbs.02.2120-21794      0.000019 write(3, "\34\0\0\0\3select @@collation_database", 32) = 32
mysql-backup-dbs.02.2120-21794      0.000026 read(3, "\1\0\0\1\1*\0\0\2\3def\0\0\0\24@@collation_dat"..., 16384) = 89
mysql-backup-dbs.02.2120-21794      0.000061 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21794      0.000021 write(3, "E\0\0\0\3SHOW TRIGGERS LIKE 'events\\"..., 73) = 73
mysql-backup-dbs.02.2120-21794      0.000027 read(3, "\1\0\0\1\vK\0\0\2\3def\22information_schema"..., 16384) = 952
mysql-backup-dbs.02.2120-21794      0.000272 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21794      0.000020 write(3, "+\0\0\0\3SET SESSION character_set_r"..., 47) = 47
mysql-backup-dbs.02.2120-21794      0.000029 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
mysql-backup-dbs.02.2120-21794      0.000052 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21794      0.000020 write(3, ")\0\0\0\3show table status like 'fil"..., 45) = 45
mysql-backup-dbs.02.2120:21794      0.000027 read(3, "3\0\0\1\377\210\4#08S01Got an error writin"..., 16384) = 55
mysql-backup-dbs.02.2120-21794      0.000180 write(2, "mysqldump: Couldn't execute 'sho"..., 122) = 122
mysql-backup-dbs.02.2120-21794      0.000022 write(3, "\1\0\0\0\1", 5) = 5
mysql-backup-dbs.02.2120-21794      0.000025 shutdown(3, 2 /* send and receive */) = 0
mysql-backup-dbs.02.2120-21794      0.000016 close(3)            = 0
mysql-backup-dbs.02.2120-21794      0.000035 munmap(0x2aaaaacca000, 1048576) = 0
--
mysql-backup-dbs.02.2120-21800      0.000020 write(3, "L\1\0\0\3SELECT DISTINCT TABLESPACE_"..., 336) = 336
mysql-backup-dbs.02.2120-21800      0.000319 read(3, "\1\0\0\1\6P\0\0\2\3def\22information_schema"..., 16384) = 489
mysql-backup-dbs.02.2120-21800      0.000033 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21800      0.000020 write(3, "\f\0\0\0\2reg_auth_db", 16) = 16
mysql-backup-dbs.02.2120-21800      0.000042 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
mysql-backup-dbs.02.2120-21800      0.000025 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21800      0.000019 write(3, "\f\0\0\0\3show tables", 16) = 16
mysql-backup-dbs.02.2120-21800      0.000284 read(3, "\1\0\0\1\1]\0\0\2\3def\22information_schema"..., 16384) = 1459
mysql-backup-dbs.02.2120-21800      0.000044 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21800      0.000021 write(3, "*\0\0\0\3show table status like 'ACC"..., 46) = 46
mysql-backup-dbs.02.2120:21800      0.000394 read(3, "3\0\0\1\377\210\4#08S01Got an error writin"..., 16384) = 55
mysql-backup-dbs.02.2120-21800      0.005884 write(2, "mysqldump: Couldn't execute 'sho"..., 123) = 123
mysql-backup-dbs.02.2120-21800      0.000031 write(3, "\1\0\0\0\1", 5) = 5
mysql-backup-dbs.02.2120-21800      0.000098 shutdown(3, 2 /* send and receive */) = 0
mysql-backup-dbs.02.2120-21800      0.000016 close(3)            = 0
mysql-backup-dbs.02.2120-21800      0.000019 munmap(0x2aaaaacca000, 1048576) = 0
--
mysql-backup-dbs.02.2120-21804      0.000019 write(3, "\34\0\0\0\3select @@collation_database", 32) = 32
mysql-backup-dbs.02.2120-21804      0.000026 read(3, "\1\0\0\1\1*\0\0\2\3def\0\0\0\24@@collation_dat"..., 16384) = 91
mysql-backup-dbs.02.2120-21804      0.000062 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21804      0.000019 write(3, "-\0\0\0\3SHOW TRIGGERS LIKE 'ACCOUNT"..., 49) = 49
mysql-backup-dbs.02.2120-21804      0.000028 read(3, "\1\0\0\1\vK\0\0\2\3def\22information_schema"..., 16384) = 952
mysql-backup-dbs.02.2120-21804      0.000349 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21804      0.000021 write(3, "+\0\0\0\3SET SESSION character_set_r"..., 47) = 47
mysql-backup-dbs.02.2120-21804      0.000027 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
mysql-backup-dbs.02.2120-21804      0.000063 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21804      0.000021 write(3, "2\0\0\0\3show table status like 'ACC"..., 54) = 54
mysql-backup-dbs.02.2120:21804      0.000027 read(3, "3\0\0\1\377\210\4#08S01Got an error writin"..., 16384) = 55
mysql-backup-dbs.02.2120-21804      0.004751 write(2, "mysqldump: Couldn't execute 'sho"..., 131) = 131
mysql-backup-dbs.02.2120-21804      0.000022 write(3, "\1\0\0\0\1", 5) = 5
mysql-backup-dbs.02.2120-21804      0.000026 shutdown(3, 2 /* send and receive */) = 0
mysql-backup-dbs.02.2120-21804      0.000016 close(3)            = 0
mysql-backup-dbs.02.2120-21804      0.000020 munmap(0x2aaaaacca000, 1048576) = 0
--
mysql-backup-dbs.02.2120-21808      0.000019 write(3, "\34\0\0\0\3select @@collation_database", 32) = 32
mysql-backup-dbs.02.2120-21808      0.000025 read(3, "\1\0\0\1\1*\0\0\2\3def\0\0\0\24@@collation_dat"..., 16384) = 91
mysql-backup-dbs.02.2120-21808      0.000062 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21808      0.000020 write(3, ".\0\0\0\3SHOW TRIGGERS LIKE 'ACCOUNT"..., 50) = 50
mysql-backup-dbs.02.2120-21808      0.000028 read(3, "\1\0\0\1\vK\0\0\2\3def\22information_schema"..., 16384) = 952
mysql-backup-dbs.02.2120-21808      0.000347 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21808      0.000020 write(3, "+\0\0\0\3SET SESSION character_set_r"..., 47) = 47
mysql-backup-dbs.02.2120-21808      0.000028 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
mysql-backup-dbs.02.2120-21808      0.000054 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
mysql-backup-dbs.02.2120-21808      0.000019 write(3, "9\0\0\0\3show table status like 'ACC"..., 61) = 61
mysql-backup-dbs.02.2120:21808      0.000026 read(3, "3\0\0\1\377\210\4#08S01Got an error writin"..., 16384) = 55
mysql-backup-dbs.02.2120-21808      0.000437 write(2, "mysqldump: Couldn't execute 'sho"..., 138) = 138
mysql-backup-dbs.02.2120-21808      0.000022 write(3, "\1\0\0\0\1", 5) = 5
mysql-backup-dbs.02.2120-21808      0.000026 shutdown(3, 2 /* send and receive */) = 0
mysql-backup-dbs.02.2120-21808      0.000015 close(3)            = 0
mysql-backup-dbs.02.2120-21808      0.000020 munmap(0x2aaaaacca000, 1048576) = 0

Thank you for the report.

According to strace few timeouts were hit when query show table status like 'ACC' was running. Is ACC federated table?

We have some that are FEDERATED and some not that start with ACC_.  However, even on dumping of performance_schema, we still see the issue, from what I can tell:

mysqldump-performance_schema-08-08-1230.log.5
-- Connecting to localhost...
-- Starting transaction...
-- Retrieving table structure for table cond_instances...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_current...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_history...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_history_long...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_summary_by_instance...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_summary_by_thread_by_event_name...
-- Sending SELECT query...
-- Retrieving rows...
-- Retrieving table structure for table events_waits_summary_global_by_event_name...
-- Sending SELECT query...
-- Retrieving rows...
mysqldump: Couldn't execute 'show table status like 'file\_instances'': Got an error writing communication packets (1160)

Which appears to correlate with:
2815       0.000096 read(3, "\1\0\0\1\20b\0\0\2\3def\22performance_schema"..., 16384) = 1705
2815       0.000056 write(2, "-- Retrieving rows...\n", 22) = 22
2815       0.000028 write(1, "/*!40000 ALTER TABLE `cond_insta"..., 1286) = 1286
2815       0.000025 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000019 write(3, "-\0\0\0\3SET SESSION character_set_r"..., 49) = 49
2815       0.000054 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
2815       0.000025 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000019 write(3, "\31\0\0\0\3use `performance_schema`", 29) = 29
2815       0.000045 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
2815       0.000023 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000019 write(3, "\34\0\0\0\3select @@collation_database", 32) = 32
2815       0.000058 read(3, "\1\0\0\1\1*\0\0\2\3def\0\0\0\24@@collation_dat"..., 16384) = 89
2815       0.000030 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000020 write(3, ",\0\0\0\3SHOW TRIGGERS LIKE 'events\\"..., 48) = 48
2815       0.000260 read(3, "\1\0\0\1\vK\0\0\2\3def\22information_schema"..., 16384) = 952
2815       0.000034 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000020 write(3, "+\0\0\0\3SET SESSION character_set_r"..., 47) = 47
2815       0.000052 read(3, "\7\0\0\1\0\0\0\3\0\0\0", 16384) = 11
2815       0.000026 poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
2815       0.000020 write(3, "0\0\0\0\3show table status like 'eve"..., 52) = 52
2815       0.000183 read(3, "3\0\0\1\377\210\4#08S01Got an error writin"..., 16384) = 55
2815       0.000053 write(2, "mysqldump: Couldn't execute 'sho"..., 129) = 129
2815       0.000023 write(3, "\1\0\0\0\1", 5) = 5
2815       0.000065 shutdown(3, 2 /* send and receive */) = 0
2815       0.000016 close(3)            = 0
2815       0.000019 munmap(0x2aaaaacca000, 1048576) = 0
2815       0.000041 write(1, "/*!40000 ALTER TABLE `events_wai"..., 75) = 75
2815       0.000032 exit_group(2)       = ?

I think that means that it happens on databases that have no FEDERATED tables (i.e., the core performance_schema) database.

Oct 22:27] murjan
Description:
I use mysqldump with Ashay OBS to backup my database.
The database is running a master master configuration, and I use one for production and the other for fallback and runs the backup from it too.

I'm starting to get these errors when running the mysqldump. Not every day, but almost.

mysqldump: Couldn't execute 'FLUSH /*!40101 LOCAL */ TABLES': Got an
error writing communication packets (1160)

The consequence does not seem to be severe, but I dont like such messages.

Recently I upgraded the fallback server from 5.1.41-3 to 5.5.24-0, thus I suspect that this behaviour is related to 5.5.24-0

I have been googling for a long time but I haven't found any similar examples of this behaviour.

 

How to repeat:
Run this command
/usr/bin/mysqldump --master-data=2 --routines --single-transaction --quick --routines $*
[9 Oct 14:08] Miguel Solorzano 
Thank you for the bug report. Looks like duplicate of http://bit.ly/SWkmsV . Please check for duplicate/related behavior.

I dont know if this of relevance, but when this is what I usually see in Ashay's log. It seems that the error only occurs for me when dumping information_schema. 

1 	Info 	2012/11/21 05:00 	Start [ Linux 2.6.32-41-generic (tgsql02), DLXOBM 6.7.2.8 ]
2 	Info 	2012/11/21 05:00 	Start running pre-commands
3 	Info 	2012/11/21 05:00 	Finished running pre-commands
4 	Info 	2012/11/21 05:00 	Using Temporary Directory /root/.obm/cache/1306332126883
5 	Info 	2012/11/21 05:00 	[Start] Backing up database "information_schema" to "/root/.obm/cache/
1306332126883/MySQL/information_schema.sql"
6 	Error 	2012/11/21 05:00 	mysqldump: Couldn't execute 'FLUSH /*!40101 LOCAL */ TABLES': Got an
error writing communication packets (1160)
7 	Info 	2012/11/21 05:00 	[End]
8 	Info 	2012/11/21 05:00 	[Start] Backing up database "ICH2-data" to "/root/.obm/cache/
1306332126883/MySQL/ICH2-data.sql"
9 	Info 	2012/11/21 05:00 	[End]

Thank you for the feedback.

> I dont know if this of relevance, but when this is what I usually see in Ashay's log. It seems that the error only occurs for me when dumping information_schema. 

Which version of mysqldump you use?

Last question from Sveta. Thanks.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

The bug exist in mysql 5.5.30, too.

Leandro ,

thank you for the feedback.

Which exact error do you get?

I can get error "mysqldump: Couldn't execute 'SELECT /*!40001 SQL_NO_CACHE */ * FROM `KEY_COLUMN_USAGE`': Unable to connect to foreign data source: Can't connect to MySQL server on '127.0.0.1' (111) (1429)" while backing up information_schema database with option --single-transaction, but don't get any error for flush local tables;

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

Our replication have failed on this bug quite a few times lately. From the replication log we see this

Last_SQL_Error: Error 'Got an error reading communication packets' on query. Default database: 'mobileprepaid'. Query: 'CREATE TABLE federatedtables.`mobilePrepaidUserID` AS SELECT `mobilePrepaidUserID` FROM federatedtables.vipteluser_mobileprepaiduser WHERE IsDeleted = 0'

It is an SQL function which needs to join with some external data, so to speed up things it creates a copy of the table. The table only has 564 elements, no text blob or any big items. But the federation goes across the internet.

All in all, it seems that the error is a timeout problem. Either adding longer timeouts or more retries might be a way to make this error go away. 
On the other hand, maybe federated tables should not be used.

Kjeld,

thank you for the feedback. You are absolutely correct regarding to timeout and federated tables. But your case most likely is not a bug: simply slave has issues when connects to the server where source table for the federated is located. Also, to prove that original case is MySQL bug we need more information.

We have a nightly cron job running at 03.00 and that nightly job fails sometimes, not all the times.
The MySQL server is on the same machine, this is the bash script we run:
DATABASE="xibdb1"
DUMP="/opt/db/mysql/mysql/bin/mysqldump"
DATE=`date +%y%m%d-%H%M%S`
DIR="/opt/db/mysql/backup/"
BZIP="/usr/bin/bzip2"
GZIP="/usr/bin/gzip"
SOCKET="/opt/db/mysql/mysql/tmp/mysql.sock"
BKP_USER="*******"
BKP_USERPASS="*******"

if [ ! -d $DIR ]; then
  mkdir -p $DIR
fi

$DUMP --user=$BKP_USER --password=$BKP_USERPASS --socket=$SOCKET  --single-transaction \
--routines --master-data=2 --databases APDBP01 SLA konrad | $GZIP > $DIR/Backup-$DATABASE-$DATE.sql.gz

The error we get is this:
mysqldump: Couldn't execute 'FLUSH /*!40101 LOCAL */ TABLES': Got an error writing communication packets (1160)

The tables are NOT federated in the databases being dumped.
This definitly seems to be a bug.

Seeing the same problem here, on 5.6.14. Previously with 5.5.25 we had it every once in a while on 5.6.14 is pretty much every night the backup fails with this error.

Running the exact same command on the command line it seems complete more often but that could be a timing / load thing as the auto backups are @ 3am where as when they are run manually its during the day.

This problem happens on 5.5.28. 

Sometimes, the first run have this error:
 mysqldump: Couldn't execute 'FLUSH /*!40101 LOCAL */ TABLES': Got an error writing communication packets (1160)

But running it again, everything is fine. 

Is there any answer/fix ?

Thanks

Thank you for the feedback.

All reporters who do *not* use federated tables, please send output of SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES

mysql> SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES;
+----------+
| COUNT(*) |
+----------+
|      142 |
+----------+

mysql> SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES;
+----------+
| COUNT(*) |
+----------+
|     1643 |
+----------+
1 row in set (0.03 sec)

mysql>

mysql> SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES;
+----------+
| COUNT(*) |
+----------+
|      948 |
+----------+
1 row in set (0.03 sec)

Hi All,

i am getting the error below when I am taking mysqldump of databaes. Please give me resolution of this error. 

mysqldump: Couldn't execute 'SELECT /*!40001 SQL_NO_CACHE */ * FROM `KEY_COLUMN_USAGE`': Unable to connect to foreign data source: Access denied for user 'repl'@'%' to database 'CMCDB' (1429)

Thanks 
Bharat Parshad

Thank you for the feedback.

I still cannot repeat any connection failure if don't backup Information Schema with version 5.6. So I can only verify it as "mysqldump fails due to timeout when backups Information Schema database if one of other databases contains Federated table which is pointed to a server which is not accessible." But this is technically feature request.

I need repeatable test case to verify failures of backing up other databases.

I'm facing same problem from last 2 month

mysql> SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES;
+----------+
| COUNT(*) |
+----------+
|    45138 |
+----------+

need proper solution on this.

Posted by developer:
 
Has anyone encountered this is 5.5.42, 5.6.23, 5.7.6, or later?

If not, this is a duplicate of Bug 20224202.

Using a slightly modified test case from Bug 17599258:

In 5.6.18:

5.6.18_fedclient: world> SELECT NOW(), City.* FROM City WHERE ID = 130; DO SLEEP(130); SHOW TABLE STATUS LIKE 'City';
+---------------------+-----+--------+-------------+-----------------+------------+
| NOW()               | ID  | Name   | CountryCode | District        | Population |
+---------------------+-----+--------+-------------+-----------------+------------+
| 2015-12-02 08:42:15 | 130 | Sydney | AUS         | New South Wales |    3276207 |
+---------------------+-----+--------+-------------+-----------------+------------+
1 row in set (0.00 sec)

Query OK, 0 rows affected (2 min 10.00 sec)

ERROR 1160 (08S01): Got an error writing communication packets

In 5.6.23:

5.6.23_fedclient: world> SELECT NOW(), City.* FROM City WHERE ID = 130; DO SLEEP(130); SHOW TABLE STATUS LIKE 'City';
+---------------------+-----+--------+-------------+-----------------+------------+
| NOW()               | ID  | Name   | CountryCode | District        | Population |
+---------------------+-----+--------+-------------+-----------------+------------+
| 2015-12-02 09:05:23 | 130 | Sydney | AUS         | New South Wales |    3276207 |
+---------------------+-----+--------+-------------+-----------------+------------+
1 row in set (0.00 sec)

Query OK, 0 rows affected (2 min 10.00 sec)

+------+-----------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+-------------+-------------+------------+-------------------+----------+----------------+---------+
| Name | Engine    | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation         | Checksum | Create_options | Comment |
+------+-----------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+-------------+-------------+------------+-------------------+----------+----------------+---------+
| City | FEDERATED |      10 | Fixed      | 4188 |             97 |      406236 |               0 |            0 |         0 |              0 | NULL        | NULL        | NULL       | latin1_swedish_ci |     NULL |                |         |
+------+-----------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+-------------+-------------+------------+-------------------+----------+----------------+---------+
1 row in set (0.01 sec)