mysql max connections limit check increase how to decide thread cache size

mysql max connections limit check query commanding

mysql -u root -p

Password:

mysql> SHOW VARIABLES LIKE “max_connections”;

+—————–+——-+
| Variable_name | Value |
+—————–+——-+
| max_connections | 151 |
+—————–+——-+
1 row in set (0.01 sec)

To view max Reached Mysql Connections since the Server start

SHOW GLOBAL STATUS LIKE ‘max_use%’;

+—————————+———————+
| Variable_name | Value |
+—————————+———————+
| Max_used_connections | 38 |
| Max_used_connections_time | 2021-06-08 02:39:27 |
+—————————+———————+

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mysql max connections recommended settings (how to choose)

In digital ocean manged sql limits

350 MB used Operating system.

750MB = 100MB per connection

4GB RAM Mysql dedicated machine 3.6GB usable and 3Gb*75=225

mysql max connections calculator

Update max connection limit in mysql.conf

Check max used connections by mysql previous

maximum number of connections that have been in use simultaneously since the server started.

Aborted connection mysql

https://journeyontux.files.wordpress.com/2011/12/max_connection_measurements.xls

mysql> SHOW STATUS LIKE ‘Threads_connected’;
+——————-+——-+
| Variable_name | Value |
+——————-+——-+
| Threads_connected | 1 |
+——————-+——-+
1 row in set (0.00 sec)

also follow mysql memory allocation & optimization

Show threads currently running on MySQL DB instance

SHOW FULL PROCESSLIST\G

increasing thread_cache_size to allow more simultaneous users

max_used_connections is 151, and your current value for thread_cache_size is 10,

then you have a problem

thread_cache_size should be greater than Max_used_connections.

SHOW GLOBAL STATUS LIKE ‘Connections’;
SHOW GLOBAL STATUS LIKE ‘Threads_created’;
SHOW GLOBAL STATUS LIKE ‘Max_used_connections’;

Threads_created / Connections : If this is over 0.01, then increase

4/427=0.001

+—————+——-+
| Variable_name | Value |
+—————+——-+
| Connections | 427 |
+—————+——-+
1 row in set (0.01 sec)

mysql> SHOW GLOBAL STATUS LIKE ‘Threads_created’;
+—————–+——-+
| Variable_name | Value |
+—————–+——-+
| Threads_created | 4 |
+—————–+——-+
1 row in set (0.00 sec)

mysql> SHOW GLOBAL STATUS LIKE ‘Max_used_connections’;
+———————-+——-+
| Variable_name | Value |
+———————-+——-+
| Max_used_connections | 4 |
+———————-+——-+
1 row in set (0.00 sec)

default mysql thread cache size is = 9 or 10

max connecton limit 151

Max_used_connectionsprevipous restrt 47

so i set thread cache size to 50

show global variables like ‘innodb_buffer_pool_size’;

thread_cache_size | 9

set global thread_cache_size = 50;

mysql> set global thread_cache_size = 50;
Query OK, 0 rows affected (0.00 sec)

my.cnf

thread_cache_size = 50;

aws rds mysql max connections

mysql too many connections fix

ERROR 1040(): Too many connections error in the MySQL error log.

when it appears you need to increase the mysql max connections per second. it needs extra memory like memory per connection. more at amz rds