Database tweaks for performance (publiclab#5575)

* Database tweaks for performance

* Reduce innodb buffer pool size because of low memory

* Reduce RAM burden

* Reduce memory consumption following mysqltuner advice.

* Even more conservative limits for RAM

config/my.cnf

@@ -1,42 +1,39 @@
-[mysqld]
-skip-host-cache
-skip-name-resolve
-datadir = /var/lib/mysql
-
-# Plots specific
-# To avoid single large file
-innodb_file_per_table = 1
-# Replication
-#server-id=2
-#log_bin = /var/lib/mysql/log/mysql-bin.log
-#binlog_do_db = publiclab_production
-# Persist socket
-socket = /var/lib/mysql/mysqld.sock
-pid-file = /var/lib/mysql/mysqld
-
-# master-host=172.17.0.1
-#replicate-do-db=publiclab_production
-#relay-log=publiclab-relay-bin
-#relay-log-index=publiclab-relay-bin.index
-
-#
-# * Fine Tuning
-#
-key_buffer		= 16M
-max_allowed_packet	= 16M
-thread_stack		= 192K
-thread_cache_size       = 8
-max_connections        =  50
-wait_timeout = 60
-#
-# * Query Cache Configuration
-#
-query_cache_limit	= 1M
-query_cache_size        = 16M
-
-# Here you can see queries with especially long duration
-slow-query-log	= 1
-slow-query-log-file = /var/lib/mysql/log/mysql-slow.log
-long_query_time = 5
-
-!includedir /etc/mysql/conf.d/
+[mysqld]
+skip-host-cache
+skip-name-resolve
+datadir = /var/lib/mysql
+
+# To avoid single large file
+innodb_file_per_table = 1
+
+socket = /var/lib/mysql/mysqld.sock
+pid-file = /var/lib/mysql/mysqld
+
+#
+# * Fine Tuning
+#
+key_buffer		= 16M
+max_allowed_packet	= 16M
+thread_stack		= 192K
+thread_cache_size       = 8
+max_connections        =  20
+wait_timeout = 60
+innodb_buffer_pool_size = 600M
+innodb_log_file_size = 150M
+join_buffer_size = 2M
+
+#
+# * Query Cache Configuration
+#
+#query_cache_limit	= 1M
+#query_cache_size        = 80M
+query_cache_limit	= 0
+query_cache_size        = 0
+# Disabled to reduce RAM overhead - we have rails cache
+
+# Here you can see queries with especially long duration
+slow-query-log	= 1
+slow-query-log-file = /var/lib/mysql/log/mysql-slow.log
+long_query_time = 5
+
+!includedir /etc/mysql/conf.d/