# PostgreSQL Production Configuration
# Custom PHP Framework - Production Optimized Settings
# PostgreSQL 16

# ============================================================================
# CONNECTIONS AND AUTHENTICATION
# ============================================================================

# Maximum number of concurrent connections
max_connections = 100

# Reserved connections for superuser emergency access
superuser_reserved_connections = 3

# ============================================================================
# MEMORY CONFIGURATION
# ============================================================================

# Shared memory for cache (25% of RAM, adjust based on available memory)
# For 4GB RAM server: 1GB
# For 8GB RAM server: 2GB
# For 16GB RAM server: 4GB
shared_buffers = 2GB

# Memory for complex sorts (per operation)
work_mem = 16MB

# Memory for maintenance operations (VACUUM, CREATE INDEX)
maintenance_work_mem = 256MB

# Maximum memory for autovacuum workers
autovacuum_work_mem = 128MB

# Effective cache size (hint for query planner, 50-75% of RAM)
effective_cache_size = 6GB

# ============================================================================
# WRITE-AHEAD LOG (WAL)
# ============================================================================

# WAL level for replication and point-in-time recovery
wal_level = replica

# Minimum size of past WAL files
min_wal_size = 1GB

# Maximum size of WAL files
max_wal_size = 4GB

# Number of WAL sender processes (for replication)
max_wal_senders = 3

# Number of replication slots
max_replication_slots = 3

# WAL keep size (for replication lag)
wal_keep_size = 1GB

# Synchronous commit (trade-off between durability and performance)
# on: Full durability (safest, slower)
# remote_apply: Wait for replica to apply (if using streaming replication)
# local: Wait for local flush (balanced)
# off: Fastest but risk of data loss on crash (NOT recommended for production)
synchronous_commit = on

# Checkpoint frequency (time between checkpoints)
checkpoint_timeout = 15min

# Target checkpoint completion time (fraction of checkpoint_timeout)
checkpoint_completion_target = 0.9

# ============================================================================
# QUERY PLANNING
# ============================================================================

# Random page cost (lower for SSD, higher for HDD)
# SSD: 1.0-1.1, HDD: 4.0
random_page_cost = 1.1

# Sequential page cost
seq_page_cost = 1.0

# Effective I/O concurrency (number of concurrent disk I/O operations)
# SSD: 200, HDD: 2-4
effective_io_concurrency = 200

# ============================================================================
# PARALLELISM
# ============================================================================

# Maximum number of parallel workers per query
max_parallel_workers_per_gather = 2

# Maximum number of parallel maintenance workers
max_parallel_maintenance_workers = 2

# Maximum number of parallel workers (total across all sessions)
max_parallel_workers = 4

# ============================================================================
# LOGGING
# ============================================================================

# Log destination
log_destination = 'stderr'

# Logging collector (rotate logs automatically)
logging_collector = on

# Log directory
log_directory = 'log'

# Log filename pattern (include date for rotation)
log_filename = 'postgresql-%Y-%m-%d.log'

# Log rotation age (daily)
log_rotation_age = 1d

# Log rotation size (500MB per file)
log_rotation_size = 500MB

# Truncate logs on rotation
log_truncate_on_rotation = on

# Log line prefix (include timestamp, user, database, PID)
log_line_prefix = '%t [%p] %u@%d '

# Log connections
log_connections = on

# Log disconnections
log_disconnections = on

# Log duration of statements (in milliseconds)
# Log only slow queries (>500ms)
log_min_duration_statement = 500

# Log lock waits (statements waiting for locks)
log_lock_waits = on

# Log checkpoints
log_checkpoints = on

# Log autovacuum activity
log_autovacuum_min_duration = 0

# ============================================================================
# AUTOVACUUM
# ============================================================================

# Enable autovacuum
autovacuum = on

# Maximum number of autovacuum workers
autovacuum_max_workers = 3

# Naptime between autovacuum runs
autovacuum_naptime = 1min

# Minimum number of updated/deleted tuples before vacuum
autovacuum_vacuum_threshold = 50

# Minimum number of inserted tuples before analyze
autovacuum_analyze_threshold = 50

# Fraction of table size to add to vacuum threshold
autovacuum_vacuum_scale_factor = 0.1

# Fraction of table size to add to analyze threshold
autovacuum_analyze_scale_factor = 0.05

# Cost delay for autovacuum (throttling)
autovacuum_vacuum_cost_delay = 10ms

# Cost limit for autovacuum
autovacuum_vacuum_cost_limit = 200

# ============================================================================
# STATISTICS
# ============================================================================

# Track activity across all databases
track_activities = on

# Track counts of rows accessed
track_counts = on

# Track I/O timing
track_io_timing = on

# Track functions
track_functions = all

# ============================================================================
# CONNECTION POOLING SUPPORT
# ============================================================================

# Prepared statements (use with PgBouncer in transaction pooling mode)
# For PgBouncer: set to 'auto' or create prepared statements per transaction
# For direct connections: 'on' for better performance
# plan_cache_mode = auto

# ============================================================================
# STATEMENT TIMEOUT
# ============================================================================

# Maximum statement execution time (30 seconds)
# Prevents long-running queries from blocking
statement_timeout = 30s

# Lock timeout (10 seconds)
# Prevents long lock waits
lock_timeout = 10s

# Idle in transaction session timeout (5 minutes)
# Closes idle transactions automatically
idle_in_transaction_session_timeout = 5min

# ============================================================================
# SECURITY
# ============================================================================

# SSL configuration (if using SSL)
# ssl = on
# ssl_cert_file = '/path/to/server.crt'
# ssl_key_file = '/path/to/server.key'
# ssl_ca_file = '/path/to/ca.crt'

# Password encryption (scram-sha-256 is most secure)
password_encryption = scram-sha-256

# ============================================================================
# CLIENT CONNECTION DEFAULTS
# ============================================================================

# Default transaction isolation level
default_transaction_isolation = 'read committed'

# Timezone
timezone = 'UTC'

# Client encoding
client_encoding = 'UTF8'

# Locale settings
lc_messages = 'en_US.UTF-8'
lc_monetary = 'en_US.UTF-8'
lc_numeric = 'en_US.UTF-8'
lc_time = 'en_US.UTF-8'

# Default text search configuration
default_text_search_config = 'pg_catalog.english'

# ============================================================================
# PERFORMANCE TUNING NOTES
# ============================================================================

# These settings are optimized for:
# - 8GB RAM server
# - SSD storage
# - Mixed OLTP/OLAP workload
# - Connection pooling via PgBouncer (optional)

# Adjust based on your hardware:
#
# For 4GB RAM server:
#   shared_buffers = 1GB
#   effective_cache_size = 3GB
#   work_mem = 8MB
#
# For 16GB RAM server:
#   shared_buffers = 4GB
#   effective_cache_size = 12GB
#   work_mem = 32MB
#
# For HDD storage:
#   random_page_cost = 4.0
#   effective_io_concurrency = 2

# ============================================================================
# MONITORING QUERIES
# ============================================================================

# Check current connections:
# SELECT count(*) FROM pg_stat_activity;

# Check slow queries:
# SELECT pid, query, now() - query_start AS duration
# FROM pg_stat_activity
# WHERE state = 'active' AND now() - query_start > interval '5 seconds';

# Check database size:
# SELECT pg_database.datname, pg_size_pretty(pg_database_size(pg_database.datname))
# FROM pg_database ORDER BY pg_database_size(pg_database.datname) DESC;

# Check table bloat (vacuum needed):
# SELECT schemaname, tablename,
#        pg_size_pretty(pg_total_relation_size(schemaname||'.'||tablename)) AS size
# FROM pg_tables WHERE schemaname = 'public' ORDER BY pg_total_relation_size(schemaname||'.'||tablename) DESC;

# Check index usage:
# SELECT schemaname, tablename, indexname, idx_scan, idx_tup_read, idx_tup_fetch
# FROM pg_stat_user_indexes ORDER BY idx_scan ASC;