When configuring AWS RDS, some of the most important database parameters depend on the engine (MySQL, PostgreSQL, SQL Server, etc.), but here are the most critical parameters across most engines:
1. Performance & Optimization
max_connections
- Defines the maximum number of concurrent database connections.
- Too low → Connection errors; Too high → Memory exhaustion. max_connections
innodb_buffer_pool_size (MySQL/MariaDB)
START Basic what is the database engine used in MySQL Back: innodb
END
START Basic Usually how much of ram will allocate for innoDB? Back: 70-80%
END
- Controls how much memory is allocated to InnoDB storage engine for caching.
- Typically set to 70-80% of available RAM for performance. Case 2
- innodb
work_mem (PostgreSQL)
START
Basic
what work_mem database parameter does?
Back:
- Determines memory allocated for sorting and hashing operations. END
START
Basic
if we increase work_mem database parameter, how it will effect for database?
Back:
-
Increasing it improves complex query performance but consumes RAM.
END
-
Determines memory allocated for sorting and hashing operations.
-
Increasing it improves complex query performance but consumes RAM.
shared_buffers (PostgreSQL)
START
Basic
what shared_buffers database parameter does?
Back:
-
Determines how much RAM is used for caching database pages.
END
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Determines how much RAM is used for caching database pages.
-
Generally set to 25-40% of total RAM. work_mem vs shared_buffers
2. Replication & High Availability
START Basic what are the main database parameters we use to optimize replication & high availability Back:
- binlog_format
- rds.repilcation_source
- wal_level END
binlog_format (MySQL)
START Basic which binlog format is best to avoid non-deterministic behavior? Back: rows
END
- Defines the binary log format (ROW, STATEMENT, MIXED).
- ROW is best for replication to avoid non-deterministic behavior.
rds.replication_source (MySQL/PostgreSQL)
- Used for setting up read replicas for scaling read operations.
wal_level (PostgreSQL)
- Controls how much information is logged for replication.
- Set to
logicalorreplicafor streaming replication.
3. Security & Access Control
rds.force_ssl
- Ensures all database connections use SSL encryption for security.
log_connections & log_disconnections (PostgreSQL)
- Helps track who is connecting/disconnecting for auditing.
rds.log_retention_period
- Defines how long logs are retained (useful for auditing & compliance).
4. Maintenance & Backups
backup_retention_period
- Sets the number of days automated backups are retained (default: 7 days).
rds.enable_auto_minor_version_upgrade
- Automatically applies minor DB version upgrades.
autovacuum (PostgreSQL)
- Cleans up dead tuples to prevent table bloat.
5. Query Logging & Monitoring
slow_query_log
- Logs queries that take longer than a specified time (useful for debugging).
long_query_time
- Defines the threshold (in seconds) for logging slow queries.
log_statement (PostgreSQL)
- Controls which SQL statements are logged (
none,ddl,mod,all).
Best Practices for AWS RDS Parameter Tuning
- Adjust memory-related settings based on instance size (e.g.,
innodb_buffer_pool_size,work_mem). - Enable logging (
slow_query_log,log_connections,binlog_format). - Optimize replication settings (
wal_level,rds.replication_source). - Set proper security parameters (
rds.force_ssl,log_connections).