Can not find a command that displays the current configuration of mysql from within the database.
I know I could look at /etc/mysql/my.cnf but that is not what I need.
What you are looking for is this:
SHOW VARIABLES;
You can modify it further like any query:
SHOW VARIABLES LIKE '%max%';
Use SHOW VARIABLES:
show variables like 'version';
As an alternative you can also query the information_schema database and retrieve the data from the global_variables (and global_status of course too). This approach provides the same information, but gives you the opportunity to do more with the results, as it is a plain old query.
For example you can convert units to become more readable. The following query provides the current global setting for the innodb_log_buffer_size in bytes and megabytes:
SELECT
variable_name,
variable_value AS innodb_log_buffer_size_bytes,
ROUND(variable_value / (1024*1024)) AS innodb_log_buffer_size_mb
FROM information_schema.global_variables
WHERE variable_name LIKE 'innodb_log_buffer_size';
As a result you get:
+------------------------+------------------------------+---------------------------+
| variable_name | innodb_log_buffer_size_bytes | innodb_log_buffer_size_mb |
+------------------------+------------------------------+---------------------------+
| INNODB_LOG_BUFFER_SIZE | 268435456 | 256 |
+------------------------+------------------------------+---------------------------+
1 row in set (0,00 sec)
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Can not find a command that displays the current configuration of mysql from within the database.
I know I could look at /etc/mysql/my.cnf but that is not what I need.
What you are looking for is this:
SHOW VARIABLES;
You can modify it further like any query:
SHOW VARIABLES LIKE '%max%';
Use SHOW VARIABLES:
show variables like 'version';
As an alternative you can also query the information_schema database and retrieve the data from the global_variables (and global_status of course too). This approach provides the same information, but gives you the opportunity to do more with the results, as it is a plain old query.
For example you can convert units to become more readable. The following query provides the current global setting for the innodb_log_buffer_size in bytes and megabytes:
SELECT
variable_name,
variable_value AS innodb_log_buffer_size_bytes,
ROUND(variable_value / (1024*1024)) AS innodb_log_buffer_size_mb
FROM information_schema.global_variables
WHERE variable_name LIKE 'innodb_log_buffer_size';
As a result you get:
+------------------------+------------------------------+---------------------------+
| variable_name | innodb_log_buffer_size_bytes | innodb_log_buffer_size_mb |
+------------------------+------------------------------+---------------------------+
| INNODB_LOG_BUFFER_SIZE | 268435456 | 256 |
+------------------------+------------------------------+---------------------------+
1 row in set (0,00 sec)
I am trying to insert base64_encoded data in Db, but it says 'Mysql server has gone'. I have taken Blob type for inserting data then also it is not inserting.
set max_allowed_packet to a higher value (your value * x) in the /etc/my.cnf and restart the server and try again
check before and after restart
MariaDB [your_schema]> show variables like 'max_allowed_packet';
+--------------------+---------+
| Variable_name | Value |
+--------------------+---------+
| max_allowed_packet | 1048576 |
+--------------------+---------+
Every socket of MySQL Database will have defaults connections as 100 but I am looking for any way to increase the number of possible connections > 100 to a socket connection of MySQL Database.
If you need to increase MySQL Connections without MySQL restart do like below
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 100 |
+-----------------+-------+
1 row in set (0.00 sec)
mysql> SET GLOBAL max_connections = 150;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 150 |
+-----------------+-------+
1 row in set (0.00 sec)
These settings will change at MySQL Restart.
For permanent changes add below line in my.cnf and restart MySQL
max_connections = 150
From Increase MySQL connection limit:-
MySQL’s default configuration sets the maximum simultaneous connections to 100. If you need to increase it, you can do it fairly easily:
For MySQL 3.x:
# vi /etc/my.cnf
set-variable = max_connections = 250
For MySQL 4.x and 5.x:
# vi /etc/my.cnf
max_connections = 250
Restart MySQL once you’ve made the changes and verify with:
echo "show variables like 'max_connections';" | mysql
EDIT:-(From comments)
The maximum concurrent connection can be maximum range: 4,294,967,295. Check MYSQL docs
I had the same issue and I resolved it with MySQL workbench, as shown in the attached screenshot:
in the navigator (on the left side), under the section "management", click on "Status and System variables",
then choose "system variables" (tab at the top),
then search for "connection" in the search field,
and 5. you will see two fields that need to be adjusted to fit your needs (max_connections and mysqlx_max_connections).
Hope that helps!
The system does not allow me to upload pictures, instead please click on this link and you can see my screenshot...
I have followed a few tutorials in tracking down slow queries through the slow query log.
I have tried changing long_query_time to the value of 1 for testing purposes, but whatever I do, a query only makes it into the log when the default time of 10 is reached.
I tried:
set ##GLOBAL.long_query_time = 1;
set global long_query_time = 1;
When using either of these commands:
show variables like '%long%';
show global variables like '%long%';
I get the result that the variable was changed.
I have the exact same query running, just adding more LEFT JOIN entries to make it run longer. Whenever the query runs 10 seconds or longer, it is logged, but it does NOT show up in the log when it runs less than that, even though all my variables appear to say they are changed.
I am logged into MySQL as root as I make these changes.
I restarted Apache and MySQL, still no dice.
My version information is:
Server version: 5.1.63-log SUSE MySQL RPM
When I query both the session and the global variables (I tried both), I get this:
mysql> show variables like '%long%';
+--------------------+----------+
| Variable_name | Value |
+--------------------+----------+
| long_query_time | 1.000000 |
| max_long_data_size | 1048576 |
+--------------------+----------+
2 rows in set (0.00 sec)
mysql> show global variables like '%long%';
+--------------------+----------+
| Variable_name | Value |
+--------------------+----------+
| long_query_time | 1.000000 |
| max_long_data_size | 1048576 |
+--------------------+----------+
2 rows in set (0.00 sec)
The general logging feature is obviously on, and it is redirected to TABLE or I wouldn't get an entry in the log at all.
The setting log_queries_not_using_indexes if turned on starts logging EVERY query even if it does not take 1 second to execute.
What am I missing?
Thanks!
The configuration below turns MySQL to log queries which execution time is more than half second:
slow_query_log = 1
long_query_time = 0.5
log-slow-queries = /var/log/mysql/log-slow-queries.log
log_queries_not_using_indexes = 0
Is there a command in MySQL that returns the read-to-write ratio of queries so that I'm able to know on what MySQL spends time, and whether the load would lower significantly by splitting data over two servers?
This SQL command will give you an indication as to the read/write ratio:
SHOW GLOBAL STATUS WHERE Variable_name = 'Com_insert'
OR Variable_name = 'Com_update'
OR Variable_name = 'Com_select'
OR Variable_name = 'Com_delete';
3rd party edit
On one of our servers gave this result
Variable_name | Value
Com_delete | 6878
Com_insert | 5975
Com_select | 101061
Com_update | 9026
Bytes_received | 136301641 <-- added by 3rd party
Bytes_sent | 645476511 <-- added by 3rd party
I assume that update and insert have different IO implications but i combined them like this Com_insert + Com_update / Com_select to get a "write/read" idea. I also use Bytes_received and Bytes_sent - but this might lead to false conclusions since bytes received do not have to lead to a write on disk (for example a long where clause).
SELECT (136263935/1000000) AS GB_received
, (644471797/1000000) AS GB_sent
, (136263935/644471797) AS Ratio_Received_Sent
, (6199+9108)/106789 AS Ins_Upd_Select_ratio;
This gave this result
GB_received | GB_sent | Ratio_Received_Sent | Ins_Upd_Select_ratio
136 | 644 | 0,2114 | 0,1433
You can use the "show status" and check the "Com_%" variables for read/write ratios.
As for splitting the data, you'll have to check the slow query log (Google mysqlsla) and find out if those queries are amicable to being split.
http://forums.mysql.com/read.php?10,328920,337142#msg-337142
"SHOW GLOBAL STATUS LIKE 'Com%'. This will give overall counts (since last restart) of each statement type. This will not necessarily tell you whether you are mostly SELECT-bound versus write-bound. You might have a small number in Com_select, but the selects are terribly slow. "