Hands-on Webinar Camunda BPM 7.2 Per formance and Scalability
Hands-on Webinar
Camunda BPM 7.2
Performance and Scalability
Daniel Meyer
Process Engine Expert
Technical Project Lead
@meyerdan | [email protected]
Bernd Rücker
10+ years experience with workflow and Java
Co-Founder of Camunda
Evangelist & Head of Consulting
@berndruecker | [email protected]
Your speakers today
Performance is a difficult topic
It always depends
−On hardware
−On software environment (OS, Java, App Server, Database, …)
−On Service Tasks in the process
−On network topology (e.g. remote database, web services, …)
−On concurrent requests, database load, …
There is no simple answer to performance
But we always succeed – in each and every real-life situation
−Handling millions of process instances / day
−Handling more than 1.000 process instances / second
−Handling thousands of parallel users
Performance is a difficult topic
We are much faster than competition
see http://camunda.com/landing/whitepaper-camunda-jbpm/
In our tests, Camunda‘s throughput was 10x – 30x higher than with JBoss jBPM.
1. Understand basic engine architecture
2. Understand influence parameters on performance
3. Discuss performance improvement approaches
4. See example figures / measurements
5. Discuss future scenarios (e.g. sharding, NoSQL, …)
What we do today
Basic Engine Architecture
We use Optimistic Locking
Runtime vs. History Database
Runtime database schema
Learning #1: The architecture it damn simple – and the bottleneck is not the process engine!
Biggest influence on Performance
Database Delegation Code
Call Service
Clustering via shared database
Learning #2: All state is in the database so clustering gets really easy. camunda scales! More on this later…
„But what can I do if performance IS a problem?“
1. Tasklist
2. (History) Queries
3. Job Execution
Typical Areas of performance issues
Process/Task Variables
−Show in list
−Use in Search/Filter
Support for Pagination
Big number of users accessing the tasklist very often
Implementation challenge
Provide a generic database schema
Complex data types are serialized – no SQL-JOIN possible
Variables are stored in one row per variable – multiple SQL-JOINs might be required
Some customers use 10-30 variables
Tasklist Requirements
Add Process Variables optimized (and only used) for Queries
−Extract attributes
−Combine variables to work with LIKE
Use own queries
−Native – if you want to improve the WHERE
−Custom – if you want to SELECT multiple information at once
Own TaskInfo or ProcessInstanceInfo entities
−Persisted as MyBatis or JPA entities
−Combine all attributes – allow to query tasks without (or with one) JOIN only
−Synchronisation via Listener – or use ProcessInstanceInfo as single source
Solution Approaches: Tasklist
Example
Customer
- customerId - company - …
Your DB camunda
PROCESS_VARIABLES
customerId ... searchField
4711 ... 4711#camunda#Berlin#...
1
2
Native Query:
3
Custom Query:
4
Java API – results are
camunda „Task“ entities
Own MyBatis mapping – result can be anything.
Called via custom code.
Example
TaskInfo
- taskId - customerId - companyName - contractId - productName - …
Your DB
camunda
PROCESS_VARIABLES
customerId contractId productId
4711 0815 42
5
TaskInfo Entity (or ProcessInstanceInfo)
The challenge:
−Indexes cost space and performance in writing data
−We provide a generic database schema without knowing what you exactly do with it
−We constantly work on the right balance of too many and too less indexes
What you can do:
−Check indexes and slow query log
−Add index where appropriate for your situation (perfectly OK with us, you do not loose support!)
−As Enterprise Customer you can always discuss/validate changes with support
Example: create index PROC_DEF_ID_END_TIME ON ACT_HI_PROCINST (PROC_DEF_ID_,END_TIME_)
(History) Queries
You can also customize history
Custom History (e.g.
ElasticSearch)
Different History Levels: - NONE - ACTIVITY - AUDIT - FULL - CUSTOM (own Filter written
in Java, e.g. „only variable X“, „not process Y“, …)
Example for custom log level: https://github.com/camunda/camunda-bpm-examples/tree/master/process-engine-plugin/custom-history-level
Job Execution
Asynchronous Continuation involve Jobs
Jobs are stored in the database
Job Executor can be configured
−Number of Worker Threads
−Number of Jobs fetched with one database query
−Size of in-memory Queue
−Lock Time, Retry Behavior, …
Job Execution can be distributed over a Cluster
Optimizing is not a straight forward task, hard to give general advise
If you need to improve: Measure and benchmark configurations in your environment!
Job Execution
The good news: We did big performance improvements in Camunda BPM 7.2!
Improved First Level Cache (throughput increased by up to 90% if async Service Tasks are executed in a row)
Improved locking to have less Optimistic Lock Exceptions and more Jobs acquired per Acquisition. Results in bigger Clusters getting possible.
Job Execution in Camunda BPM 7.2
Recap:
Added log level “CUSTOM” for History
First Level Cache
Job Executor Acquisition Locking
Plus:
Added flush ordering (comparable to Hibernate) to minimize risk of deadlocks
Summary: Performance Improvements in 7.2
Learning #3: All performance challenges can be solved.
This is AWESOME!
Recommendation: Measure! No guessing.
camunda engine
Process Application
External Load
Generator
e.g. JMeter, HP Load Runner, CURL, …
REST
„close to production“ environment
- Measure
- JobExecutor Horizontal Scalability
- Impact of 1st level cache reuse
- Improvements Version 7.1.0 vs. Version 7.2.0
- Environment: Amazon AWS Cloud (EC2 & RDS)
Benchmark
Benchmark Setup
Client
Process Engine Node 1
Process Engine Node 2
Process Engine Node 3
Process Engine Node 4
Start Process Instance (Rest API)
Database (Postgres)
https://github.com/meyerdan/ec2-benchmark
EC2 m3.xlarge (Intel Xeon E5-2670 v2, 4 core, 15 GiB Memory)
EC2 m3.xlarge (Intel Xeon E5-2670 v2, 4 core, 15 GiB Memory)
EC2 db.m3.xlarge (Intel Xeon E5-2670 v2, 4 core, 15 GiB Memory)
Provisioned using Docker
EC2
Benchmark Setup - The process
- All service tasks „Async“ - 1st service task creates 5 variables - Variables are read by subsequent service tasks
Throughput in terms of transactions / second
No absolute Numbers
Benchmark Results
Benchmark Results (1)
Benchmark Results (1)
Benchmarks Results (2)
Benchmarks Results
Cache Off Cache On
Amazon RDS Metrics
Benchmarks Results
Cache Off
Cache On
Amazon RDS Metrics
What about true Horizontal Scalability?
What is Horizontal Scalability? Scale up the number of transactions executed by adding more processing nodes to the system. [*] [*] http://en.wikipedia.org/wiki/Scalability#Horizontal_and_vertical_scaling (Adapted)
Horizontal Scalability
transactions / sec
nodes
The current Situation
Scale number of Process Engine Nodes (JVMs) Up to a certain point
Limited possibilities for scaling the shared relational Database. In a sense this can only be scaled “up”, not “out”.
Shared Relational Database
Process Engine
Process Engine
Process Engine
Which way to go?
Distributed Datastore
Process Engine
Process Engine
Process Engine
Distributed Datastore. Use a database which is itself a distributed system and can be scaled horizontally.
- Apache Cassandra, - Apache HBase, - Distributed Caches
(Hazelcast, …) - ...
Sharding and partitioning. Distribute the state over multiple Datastores.
- Multiple instances of PostgreSQL
- Each “DB” is a Mongo DB shard
- No “DB” at all: use a filesystem journal?
- ...
Key Difference: on the right hand side, the process engine itself is “distributed” in the sense that it is aware of the distribution and sharding.
The problem with Distributed Datastores
(In the context of process engines)
1. Consistency guarantees offered by these databases (eventual consistency, ACID vs.
BASE, ...) often do not match the requirements of BPMN process execution. See:
conflicting concurrent transactions: a. Racing incoming signals (E.g.: Two Messages targeting the same event instance arrive at the
same time)
b. Joins & Synchronization (E.g.: Gateways, Multi Instance, ...)
c. Cancel Activity instance (E.g.: Interrupting Message Boundary Event)
1. Data Representation and Network Latency / Overhead: Process instance state is
composite: a. Token state / active activity instances
b. Variables
c. Task Information, …
Challenge is to find a data representation which does not lead to distribution of the state of a
single process instance across the cluster while still supporting the required access patterns.
2. Significant differences between individual technologies while there are no
industry standards in place yet. (Different with SQL).
Sharding => Distributed yet Local
Scale horizontally...
Each “shard / node” maitains its state locally Partitioning workflow instance state - Each process instance lives inside a single shard / partition => local data consistency easy to guarantee, => easy to access efficiently => Support range of different persistence engines (Relational Database, Non-Relational Databases, …)
Process
Engine
Flexible Architecture
...
Reality @ zalando 2014
Process
Engine
Process
Engine
The simplest case A single process engine node
running on top of a conventional database.
A medium Scenario Horizontally scale on top of a
conventional database.
Massive Compute Cluster 500 Nodes ?
All of this should be possible with one unified architecture!
No more Search!
The catch
“Find Process Instance for order with ID 43543242” ??
???
Human Workflow (Build Task Lists) History: Monitoring, Reporting, … Message Correlation
When is „Search“ required?
Message Correlation
The Problem to solve
Workflow Instance State for order with ID 435345
Incoming Message: “customer cancelled Order
with ID 435345”
Yes, but for non-workflow execution Use Cases
Use Search Index?
(A)sync Updates
Search Index (Near Realtime)
Tasklist Queries, Monitoring,...
Vision
History Tasks Core Process Execution
Signal / Cancel Activity Instance by Id Correlate Message
Query for List of Tasks
Monitoring, Reports
Real Time, Strongly Consistent Horizontally scalable through sharding
Multiple persistence technologies possible
Near Real Time, Eventually Consistent Use best technology for the Job.
Async Event Stream
But still...
History Tasks Core Process Execution
Signal / Cancel Activity Instance by Id Correlate Message
Query for List of Tasks
Monitoring, Reports
In the simplest case!
Learning #4: You can do true horizontal clustering with the engine which exists today! There is no need for No-SQL persistence in the core engine.
Learning #5: Camunda is really damn smart :-)
Camunda BPM Performance is already awesome
However: We are continuously improving performance
There are strategies to solve specific performance challenges
There is no limit in scalability
Summary
Start now!
Open Source Edition • Download:
www.camunda.org • Docs, Tutorials etc. • Forum • Meetings
Enterprise Edition • Trial:
www.camunda.com • Additional Features • Support, Patches etc. • Consulting, Training
http://camunda.com/bpm/consultation/
[email protected] | US +1.415.800.3908 | DE +49 30 664040 900
Thank you!
Questions?