mysql

# Debian / Ubuntu — MySQL 8
sudo apt update
sudo apt install -y mysql-server

# RHEL / Amazon Linux
sudo dnf install -y mysql-server
sudo systemctl enable --now mysqld

# Run the secure installation wizard
sudo mysql_secure_installation
# Prompts: set root password, remove anonymous users, disable remote root, remove test db

# Verify
mysql --version
sudo systemctl status mysql

sudo mysql -u root -p

-- Create a database
CREATE DATABASE mydb CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

-- Create an application user with strong auth
CREATE USER 'myapp'@'%' IDENTIFIED BY 'strong_password_here';
GRANT SELECT, INSERT, UPDATE, DELETE ON mydb.* TO 'myapp'@'%';
FLUSH PRIVILEGES;

-- Verify
SHOW GRANTS FOR 'myapp'@'%';

# Connect
mysql -u myapp -p -h 127.0.0.1 mydb

# Execute a single statement
mysql -u myapp -p -e "SELECT COUNT(*) FROM orders;" mydb

# Import a SQL file
mysql -u myapp -p mydb < schema.sql

# Export query results to CSV
mysql -u myapp -p -e "SELECT * FROM users" mydb \
  | tr '\t' ',' > users.csv

-- Inside the mysql shell
SHOW DATABASES;
USE mydb;
SHOW TABLES;
DESCRIBE users;
SHOW CREATE TABLE users\G
SHOW PROCESSLIST;
SHOW ENGINE INNODB STATUS\G

[mysqld]
# -- Networking --
bind-address           = 0.0.0.0
max_connections        = 300
wait_timeout           = 600
interactive_timeout    = 600

# -- InnoDB (most impactful settings) --
innodb_buffer_pool_size   = 4G          # ~70% of RAM on a dedicated server
innodb_buffer_pool_instances = 4        # 1 per GB of pool (up to 64)
innodb_log_file_size      = 1G
innodb_flush_log_at_trx_commit = 1      # 1 = ACID; 2 = faster, slight risk
innodb_flush_method       = O_DIRECT    # avoids double buffering on Linux
innodb_io_capacity        = 2000        # raise for SSD
innodb_io_capacity_max    = 4000

# -- Query cache (disabled in MySQL 8, use ProxySQL or app cache) --
# query_cache_type = 0

# -- Logging --
slow_query_log         = 1
slow_query_log_file    = /var/log/mysql/slow.log
long_query_time        = 1
log_error              = /var/log/mysql/error.log

# -- Binary log (required for replication) --
server-id              = 1
log_bin                = /var/log/mysql/mysql-bin
binlog_expire_logs_seconds = 604800     # 7 days
sync_binlog            = 1

# -- Character set --
character-set-server   = utf8mb4
collation-server       = utf8mb4_unicode_ci

# Apply changes
sudo systemctl restart mysql

# Verify a setting at runtime
mysql -u root -p -e "SHOW VARIABLES LIKE 'innodb_buffer_pool_size';"

# Single database
mysqldump -u root -p --single-transaction --routines --triggers \
  mydb > /backups/mydb_$(date +%F).sql

# All databases
mysqldump -u root -p --all-databases --single-transaction \
  > /backups/all_$(date +%F).sql

# Compressed backup
mysqldump -u root -p --single-transaction mydb \
  | gzip > /backups/mydb_$(date +%F).sql.gz

# Restore
mysql -u root -p mydb < /backups/mydb_2025-01-15.sql

# Restore compressed
gunzip < /backups/mydb_2025-01-15.sql.gz | mysql -u root -p mydb

# Install