When setting up MySQL replication in version 5.1.49, the binlog format choice fundamentally affects replication behavior, data integrity, and performance. Let's examine each format's technical characteristics:
-- Check current binlog format
SHOW VARIABLES LIKE 'binlog_format';
ROW format logs actual row changes rather than SQL statements. This is particularly crucial when:
- Using non-deterministic functions like UUID() or RAND()
- Executing complex triggers or stored procedures
- Needing precise data recovery
-- Example where ROW format is essential
UPDATE large_table SET col = UUID() WHERE id BETWEEN 1 AND 10000;
The trade-off is increased binary log size, especially for bulk operations affecting many rows.
STATEMENT format replicates the actual SQL commands. While more compact, it's prone to edge cases:
-- Potential replication inconsistency in STATEMENT mode
UPDATE accounts SET balance = balance * 1.05 WHERE user_id = 42;
This format may be suitable for simple workloads with deterministic queries, but generally not recommended for production.
MIXED mode automatically switches between ROW and STATEMENT based on query characteristics:
- Uses STATEMENT for deterministic queries (simple INSERT/UPDATE)
- Switches to ROW for non-deterministic operations
-- Configuration example
SET GLOBAL binlog_format = 'MIXED';
SET GLOBAL binlog_row_image = 'FULL';
For MySQL 5.1.49 replication:
# my.cnf configuration
[mysqld]
server-id = 1
log-bin = mysql-bin
binlog-format = ROW
expire_logs_days = 7
sync_binlog = 1
Consider ROW format as your default choice unless you have specific legacy requirements. The data safety benefits typically outweigh the storage overhead.
If you encounter replication drift:
-- Verify replication consistency
CHECKSUM TABLE important_table;
-- Compare master/slave checksums
For large transactions in ROW format, monitor disk space and consider adjusting:
SET GLOBAL binlog_row_image = 'MINIMAL';
When setting up MySQL replication (specifically in version 5.1.49), the binlog format choice significantly impacts performance, data consistency, and storage requirements. Let's examine the three formats:
-- Check current binlog format
SHOW VARIABLES LIKE 'binlog_format';
Logs the actual SQL statements that modify data. Best for:
- Minimal storage usage
- Simple queries with deterministic results
- Cases where the same statement produces identical results on master and slave
-- Example of what gets logged
UPDATE users SET status='active' WHERE last_login > '2023-01-01';
Drawback: Non-deterministic functions (like UUID() or NOW()) may cause inconsistencies.
Logs changed rows rather than SQL statements. Advantages include:
- Precise data replication
- Handles non-deterministic functions correctly
- Better for stored procedures and triggers
-- Example row change representation
# at 12345
#230101 10:00:00 server id 1 end_log_pos 98765
Table_map: test.users mapped to number 14
Update_rows: table id 14 flags: STMT_END_F
BINLOG '
BASE64ENCODEDROWDATAHERE
'/*!*/;
Tradeoff: Larger binary logs and potentially slower replication for bulk operations.
Hybrid approach that uses statement-based by default but switches to row-based when needed:
- Automatic switching for non-deterministic statements
- Balance between storage efficiency and reliability
- Good for most general-purpose replication scenarios
-- Configuration example in my.cnf
[mysqld]
binlog_format = MIXED
log-bin = mysql-bin
server-id = 1
For MySQL 5.1.49 replication setups:
- Choose ROW if:
- You use stored procedures/triggers
- Need 100% data consistency
- Have non-deterministic queries
- Choose MIXED if:
- You want a balance of performance and reliability
- Have mostly deterministic statements with few edge cases
-- How to switch formats dynamically
SET GLOBAL binlog_format = 'ROW';
FLUSH LOGS;
- ROW format requires careful monitoring of disk space
- Statement-based may break with certain SQL modes
- Test thoroughly before changing formats in production
- Consider upgrading from 5.1 for better replication features