Ensuring that your end users get the performance they expect from your system requires an organized approach to performance management. This session will cover the planning and measurement necessary to ensure satisfied customers, and will also include tips and tricks learned from MariaDB’s years of supporting many of the most demanding installations in the world.

1. Maximizing
Performance via
Tuning and
Optimization
Getting the most from MariaDB
Server

2. Agenda • General Best Practices
• Server, Storage, Network and O/S
• Connections & Pooling
• MariaDB Config Settings
• Query Tuning
• Q&A

3. MariaDB Server + InnoDB

4. General Best Practices
Maybe obvious, but worth repeating

5. • Service Level Agreements (SLAs)
– Individual Biz/App Transactions
– Throughput
– Latency (at percentile)
– Peaks of peaks or favorable scheduling?
• Translate to Database Transactions
Define Target

6. Capture Metrics
• Biz/App Transactions
– Code Instrumentation
– Synthetic Transactions
– Compare to defined SLAs
• Database Transactions
• Sub-system level
– Servers (Web, App, DB, etc…)
– Storage
– Network
– Database

7. History
Alerts
Leverage your Metrics

8. Avoiding Cliffs • Understand expected business volumes
• Watch system-level stats for saturation
• Stress testing
– Sysbench
– HammerDB
– TPC
– Many others….
– Custom

9. Server, Storage, Network and O/S
Core Infrastructure

10. • Dedicated Server
• Memory
– More usually helps (up to ~dataset size)
– Important with read-heavy + slow disk
• More CPUs
– Highly concurrent use cases
– Usually favored over faster CPUs
• Faster CPUs
– Less concurrent use cases
– Dataset fits in memory
Database Server

11. • Local or SAN over NAS
– Performance
• SSD over HHD
– Performance and MTBF
– SSD wear not usually a factor
• SSDs
– Consumer
– Prosumer
– PCIe
– NVMe
Storage

12. • Can be Bandwidth Hungry
– Regular client traffic
– Replication Traffic
– Rebuilding replicas from snapshots
• Stability matters for Replication
• Sometimes overlooked as potential
bottleneck
• Efficient DNS setup*
Network

13. • vm.swappiness = 10
• ext4 or xfs for data files
• noatime for filesystem mounts
• ulimit changes
OS (Linux)
mariadb.com/kb/en/library/operating-system-optimizations/

14. Connections & Pooling
Applying Back Pressure

15. Back Pressure in the Full Stack
Firewall/LB Web Servers App Servers MaxScale MariaDB
Server(s)

16. MariaDB Connection Controls
App Servers MaxScale MariaDB
Server(s)
max_connections
wait_timeout
thread_handling
thread_pool_max_threads
thread_pool_min_threads
thread_pool_idle_timeout
...
MariaDBDataSource
MariaDBPoolDataSource
maxPoolSize
minPoolSize
...
Outbound
persistpoolmax
persistmaxtime
Inbound
max_connections
connection_timeout

17. Further Reading
• Java Connector Pooling
mariadb.com/kb/en/library/pool-datasource-implementation/
• MaxScale
mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-22/maxscale-configuration-
usage-scenarios/#server
mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-22/maxscale-configuration-
usage-scenarios/#server
• Server Thread Pools
mariadb.com/kb/en/library/thread-pool-in-mariadb/
mariadb.com/kb/en/library/thread-pool-system-and-status-variables/

18. Configuration Settings
Common Settings with Performance Impact

19. • Runtime changes via SET GLOBAL
• Make permanent with changes to my.cnf
– Make sure you have right my.cnf
– Verify with SHOW GLOBAL
• One change at a time
• Production changes
– tested, reviewed, version controlled
Changing Config
Settings
my.cnf

20. Config Settings (1 of 2)
innodb_buffer_pool_size
innodb_log_file_size
innodb_file_per_table
query_cache_size
max_connections

21. Config Settings (2 of 2)
tmp_table_size
max_heap_table_size
join_buffer_size
sort_buffer_size

22. Query Tuning
There are always more queries to tune

23. Finding Slow
Queries
slow_query_log = 1
slow_query_log-file = /var/lib/mysql/myslow.log
long_query_time = 10
Pay attention to similar queries and the
query count

24. Analyzing Slow
Queries
EXPLAIN
SELECT *
FROM employees
WHERE MONTH(birth_date) = 8 G
id: 1
select_type: SIMPLE
table: employees
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 299587
Extra: Using where

25. • Poor Indexing #1 Reason for poor
performance
• Basics of B-Tree Indexing same across
relational systems
• Space/Performance Tradeoff
• Write/Read Tradeoff
Indexing

26. • PRIMARY KEY = Clustered Index
• Secondary Indexes reference hold
primary key
– key PRIMARY KEY small
• InnoDB Table Stats
• Optimizer Hints
– https://mariadb.com/kb/en/library/optimizer-hints/
InnoDB
Indexing Tips

27. Query Tuning
SHOW STATUS
Global or Session
● Returns List of Internal Counters
● GLOBAL for System-Wide Status — Since
Start-Up
● SESSION for Local to Client Connection
● FLUSH STATUS Resets Local Counters
● Monitor Changes to Counters to Identify Hot
Spots
● Collect Periodically Status Snapshots to Profile
Traffic

28. Query Tuning
PERFORMANCE_SCHEMA
● Similar to INFORMATION_SCHEMA , but
Performance Tuning
● Monitors MariaDB Server Events
● Function Calls, Operating System Waits, Internal
Mutexes, I/O Calls
● Detailed Query Execution Stages (Parsing,
Statistics, Sorting)
● Some Features Storage Engine Specific
● Monitoring Lightweight and Requires No
Dedicated Thread
● Designed to be Used Iteratively with Successive
Refinement

29. Q&A

30. Thank you
james.mclaurin@mariadb.com.

31. Appendix
Backup Slides and More