[client]
port                           = 3306
socket                         = /tmp/mysql.sock
default-character-set          = utf8mb4

[mysql]
no-auto-rehash
default-character-set          = utf8mb4

[mysqld]
# ====================================================================
# 1. PATHS & BASIC CORE SETTINGS
# ====================================================================
user                           = mysql
port                           = 3306
basedir                        = /usr/local/mysql
datadir                        = /data/mysql
socket                         = /tmp/mysql.sock
pid-file                       = /data/mysql/mysql.pid

# ====================================================================
# 2. GLOBAL INTERNATIONALIZATION (Supports ALL Languages + Emojis)
# ====================================================================
character-set-server           = utf8mb4
collation-server               = utf8mb4_unicode_ci
init_connect                   = 'SET NAMES utf8mb4'

# ====================================================================
# 3. 4GB RAM RESOURCE SAFEGUARDS & TUTOR BUDGETS
# ====================================================================
# Disabling this saves ~400MB to 600MB of overhead instantly.
performance_schema             = 0

# Limit max connections to prevent RAM exhaustion if code loops infinitely.
max_connections                = 50
max_connect_errors             = 1000

# Enforces strict, standardized ANSI SQL (forces students to code cleanly).
sql_mode                       = "STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION,ONLY_FULL_GROUP_BY"

# Explicit timeouts for idle tutorial connections
interactive_timeout            = 600
wait_timeout                   = 600

# ====================================================================
# 4. MEMORY ALLOCATIONS (Explicitly capped under 2GB Total)
# ====================================================================
# Global Storage Buffers
innodb_buffer_pool_size        = 1G          # Primary database buffer cache
innodb_log_file_size           = 128M        # Redo log file size
innodb_log_buffer_size         = 8M          # Transaction log buffer

# Server Shared Metadata Buffers
key_buffer_size                = 16M
max_allowed_packet             = 32M
table_open_cache               = 1000

# Per-Thread Connection Buffers (Allocated per connection)
sort_buffer_size               = 512K        # Used for ORDER BY actions
join_buffer_size               = 512K        # Used for table JOIN actions
read_buffer_size               = 256K        # Sequential scan buffer
read_rnd_buffer_size           = 512K        # Random read sorting buffer

# ====================================================================
# 5. STORAGE ENGINE CONFIGURATION (InnoDB Defaults)
# ====================================================================
innodb_data_home_dir           = /data/mysql
innodb_log_group_home_dir      = /data/mysql
innodb_file_per_table          = 1           # Isolates individual tables into standalone .ibd files
innodb_flush_log_at_trx_commit = 2           # Speed preference over safety for testing/learning
innodb_stats_on_metadata       = 0

# ====================================================================
# 6. LOGGING ARCHITECTURE (Perfect for Teaching & Debugging)
# ====================================================================
# General Diagnostic Error Logging
log-error                      = /data/mysql/mysql-error.log

# Slow Query Logging (Use to teach 'EXPLAIN' syntax and index optimization)
slow_query_log                 = 1
slow_query_log_file            = /data/mysql/mysql-slow.log
long_query_time                = 2           # Captures commands executing over 2 seconds

# Binary Logging & Replication Basics
server-id                      = 1
log-bin                        = /data/mysql/mysql-bin
binlog_format                  = ROW
expire_logs_days               = 3           # Automatically wipes old binlogs to preserve disk space