Is there a way to know the bin log files path from mysql console as we can know whether its ON or OFF by using
Select * information_schema.GLOBAL_VARIABLES
where variable_name like '%log_bin%'.
Use this to show on/off:
SHOW VARIABLES LIKE 'log_bin'
Also:
SHOW GLOBAL VARIABLES LIKE '%bin%'
Or
SHOW SESSION VARIABLES LIKE ...
More Information: (notice that some of these values and results changed from 5.5 to 5.6!)
http://dev.mysql.com/doc/refman/5.5/en/show-master-status.html
mysql > SHOW MASTER STATUS;
+---------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+---------------+----------+--------------+------------------+
| mysql-bin.003 | 73 | test | manual,mysql |
+---------------+----------+--------------+------------------+
mysql> SHOW BINARY LOGS;
+---------------+-----------+
| Log_name | File_size |
+---------------+-----------+
| binlog.000015 | 724935 |
| binlog.000016 | 733481 |
+---------------+-----------+
From the docs regarding log-bin"
Setting this option causes the log_bin system variable to be set
to ON (or 1), and not to the base name. This is a known issue;
see Bug #19614 for more information.
There is a workaround using mysqld instead in the Bug 19614 which I modified a bit. If you are scripting, you can use from the mysql client (which I found a bit tedious to do, see the next workaround):
mysql >\! dirname $(mysqld --help --verbose 2> /dev/null | egrep "^log-bin " | grep -o "\/.*")
Looks like there is a patch submitted by Mark Callaghan, and it was never committed. There is a function in WP5465 (which is the work in progress for this patch), however it didn't work properly for me, as the location of the logs can be different across setups.
Related
Hello i got an error when im about to insert datas to a column a tutorial in google said to use
SET SQL_mode= 'ALLOW_INVALID DATES'
Now I got error 1265 Data truncated for column 'BDAY' And the BDAY column now shows 0000-00-00
How do I revert it back to normal or do I just reinstall mysql?
Thanks so much
If you have changed the sql_mode on your configuration files, you can run below command on Linux to find the changes:
sudo grep -ir "ALLOW_INVALID DATES" /etc/
sudo grep -ir "ALLOW_INVALID DATES" /etc/mysql/
Default configuration files on Linux are stored on the etc folder.
On your configuration file set sql_mode to save it permanently:
[mysqld]
sql-mode="ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION"
On the MySQL command line you can set it for the session and global.
First check using:
mysql> show variables like '%sql_mode%';
+---------------+-----------------------------------------------------------------------------------------------------------------------+
| Variable_name | Value |
+---------------+-----------------------------------------------------------------------------------------------------------------------+
| sql_mode | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION |
+---------------+-----------------------------------------------------------------------------------------------------------------------+
mysql> show global variables like '%sql_mode%';
+---------------+-----------------------------------------------------------------------------------------------------------------------+
| Variable_name | Value |
+---------------+-----------------------------------------------------------------------------------------------------------------------+
| sql_mode | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION |
+---------------+-----------------------------------------------------------------------------------------------------------------------+
Then you change it using:
SET GLOBAL sql_mode = 'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';
SET SESSION sql_mode = 'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';
refer to MySQL's official document: https://dev.mysql.com/doc/refman/5.7/en/hexadecimal-literals.html
its official example:
mysql> SELECT X'4D7953514C', CHARSET(X'4D7953514C');
+---------------+------------------------+
| X'4D7953514C' | CHARSET(X'4D7953514C') |
+---------------+------------------------+
| MySQL | binary |
+---------------+------------------------+
However, in my windows-MySQL5.7, I got below: (client is Heidi )
why?
OK I got it.
It's Heidi's problem, not MySQL's.
I changed another client (MySQL-front) , then the text result shown as "MySQL", not 0x4D79...
also I changed to print the query result in a .php page, the text result also shown corrently as "MySQL".
The following questions will be answered.
How to enable slow query log in MySQL
How to set slow query time
How to read the logs generated by MySQL
Log analysis is becoming a menace day-by-day. Most tech companies have started using ELK stack or similar tools for Log analysis. But what if you don't have hours to spend on the set up of ELK and just want to spend some time on analysing the logs by your on (manually, that is).
Although, it is not the best way but don't underestimate the power of analysing the logs from the terminal. From the terminal too, we can efficiently analyse the logs but there are limitations to what we can or cannot do. I am posting about the basic process of analysing a MySQL log.
(In addition to the 'setup' provided by #MontyPython...)
Run
pt-query-digest, or mysqldumpslow -s t
Either will give you the details of 'worst' query first, so stop the output after a few dozen lines.
I prefer long_query_time=1. It's in seconds; you can specify less than 1.
Also, in more recent versions, you need log_output = FILE.
show variables like '%slow%';
+---------------------------+-----------------------------------+
| Variable_name | Value |
+---------------------------+-----------------------------------+
| log_slow_admin_statements | OFF |
| log_slow_slave_statements | OFF |
| slow_launch_time | 2 |
| slow_query_log | OFF |
| slow_query_log_file | /var/lib/mysql/server-slow.log |
+---------------------------+-----------------------------------+
And then,
show variables like '%long_query%';
+-----------------+----------+
| Variable_name | Value |
+-----------------+----------+
| long_query_time | 5.000000 |
+-----------------+----------+
Change the long query time to whatever you want. Queries taking more than this will be captured in the slow query log.
set global long_query_time = 2.00;
Now, switch on the slow query log.
set global slow_query_log = 'ON';
flush logs;
Go to the terminal and check the directory where the log file is supposed to be.
cd /var/lib/mysql/
la -lah | grep slow
-rw-rw---- 1 mysql mysql 4.6M Apr 24 08:32 server-slow.log
Opening the file - use one of the following commands
cat server-slow.log
tac server-slow.log
less server-slow.log
more server-slow.log
tail -f server-slow.log
How many unique slow queries have been logged during a day?
grep 'Time: 160411.*' server-slow.log | cut -c2-18 | uniq -c
I set two user-defined variables as shown below but after some time, I forgot the names:
SET #a = 2, #b = 3;
So, does MySQL have the command that displays all user-defined variables?
Starting with MySQL 5.7, the performance schema exposes user variables.
See table performance_schema.user_variables_by_thread
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-user-variable-tables.html
If you have MariaDB (a binary "drop-in" equivalent of MySQL) there is a plugin available, provided by MariaDB itself.
MariaDB 10.2 (equivalent to MySQL 5.7) and above has a plugin that creates a "USER_VARIABLES" table.
Here is how to install the plugin.
Here is an example of its use:
SELECT * FROM information_schema.USER_VARIABLES ORDER BY VARIABLE_NAME;
+---------------+----------------+---------------+--------------------+
| VARIABLE_NAME | VARIABLE_VALUE | VARIABLE_TYPE | CHARACTER_SET_NAME |
+---------------+----------------+---------------+--------------------+
| var | 0 | INT | utf8 |
| var2 | abc | VARCHAR | utf8 |
+---------------+----------------+---------------+--------------------+
MariaDB installs the plugin by default after version MariaDB 10.2.6.
The link above shows how to install it for prior versions.
Double check what version of "mysql" you're running, because sometimes people will refer to a MariaDB as MySQL, due to its use as a "binary drop in replacement" for MySQL. So it's possible that you are running a MariaDB database.
I am not aware of MySQL providing anything similar.
How to check which version of mysql you're running (the prompt is in bold)
From the command line:
$ mysql -v
From the mysql command client:
mysql> SHOW VARIABLES LIKE "%version%";
It is also shown when you first log into the mysql command client, which you can do via:
$ mysql -u your_mysql_username --password=your_mysql_password
With performance_schema.user_variables_by_thread, you can show all user-defined variables as shown below:
mysql> SELECT * FROM performance_schema.user_variables_by_thread;
+-----------+---------------+--------------------------------+
| THREAD_ID | VARIABLE_NAME | VARIABLE_VALUE |
+-----------+---------------+--------------------------------+
| 69 | first_name | 0x4A6F686E |
| 69 | last_name | 0x536D697468 |
+-----------+---------------+--------------------------------+
I have run mysql -u root -p gf < ~/gf_backup.sql to restore my db. However when I see the process list I see that one query has has been idle for a long time. I do not know the reason why.
mysql> show processlist;
+-----+------+-----------+-------------+---------+-------+-----------+------------------------------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----+------+-----------+-------------+---------+-------+-----------+------------------------------------------------------------------------------------------------------+
| 662 | root | localhost | gf | Query | 18925 | query end | INSERT INTO `gf_1` VALUES (1767654,'90026','Lddd',3343,34349),(1 |
| 672 | root | localhost | gf | Query | 0 | NULL | show processlist |
+-----+------+-----------+-------------+---------+-------+-----------+------------------------------------------------------------------------------------------------------+
Please check free space with df -h command (if under Linux/Unix) if you're out of space do not kill or restart MySQL until it catch up with changes when you free some space.
you may also want to check max_allowed_packet setting in my.cnf and set it to something like 256M, please refer to http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_max_allowed_packet
Probably your dump is very large and contains much normalized data (records split into a bunch of tables, with a bunch of foreign key constraints, indexes and so on).
If so, you may try to remove all constraints and index definitions from the SQL file, then import the data and re-create the former removed directives. This is a well-known trick to speed up imports, because INSERT commands without validation of any constraints are a lot faster, and creation of an index and so on afterwards can be done in a single transaction.
See also: http://support.tigertech.net/mysql-large-inserts
Of course, you should kill the query first. And remove all fragments it created already.