Load balancers (Distributors)

Distributor as the part of test definition provides pairs of endpoints and queries for invokers. More...

Classes
class	com.griddynamics.jagger.invoker.CircularExclusiveAccessLoadBalancer< Q, E >
	Subclass of ExclusiveAccessLoadBalancer that circularly selects pairs of Q and E. More...
class	com.griddynamics.jagger.invoker.ExclusiveAccessLoadBalancer< Q, E >
	This com.griddynamics.jagger.invoker.LoadBalancer implementation provides guarantees that each query and endpoint pair will be in exclusive access, i.e. More...
class	com.griddynamics.jagger.user.test.configurations.loadbalancer.JLoadBalancer
	Provides load balancer aka distributor (how to pair endpoints and queries) (subtypes of QueryPoolLoadBalancer). More...
interface	com.griddynamics.jagger.invoker.LoadBalancer< Q, E >
	An object which provides pairs of queries and endpoints for Invoker. More...
class	com.griddynamics.jagger.invoker.NonCircularExclusiveAccessLoadBalancer< Q, E >
	Subclass of ExclusiveAccessLoadBalancer that provides each pair of Q and E only once (does not circle an iteration). More...
class	com.griddynamics.jagger.invoker.OneByOneLoadBalancer< Q, E >
	Schedules queries across endpoints one by one. More...
class	com.griddynamics.jagger.invoker.PairSupplierFactoryLoadBalancer< Q, E >
class	com.griddynamics.jagger.invoker.QueryPoolLoadBalancer< Q, E >
	LoadBalancer which uses query and endpoint provider. More...
class	com.griddynamics.jagger.invoker.RandomLoadBalancer< Q, E >
	Randomly selects pairs of Q and E. More...
class	com.griddynamics.jagger.invoker.RoundRobinLoadBalancer< Q, E >
	Encapsulates Round-Robin algorithm. More...
class	com.griddynamics.jagger.invoker.SimpleCircularLoadBalancer< Q, E >
	Circularly selects pairs of Q and E. More...
class	com.griddynamics.jagger.invoker.SimpleLoadBalancer< Q, E >
	Contains only one query and endpoint. More...

Detailed Description

Distributor as the part of test definition provides pairs of endpoints and queries for invokers.

Before start of the test distributor is combining all endpoints and queries according to user setup and stores these combination in internal list.
Important: mentioned list is shared by all threads that produce load. it is not possible to have separate list per workload thread
Before every invoke distributor is providing single pair of endpoint / query to invoker
Endpoints and queries can be combined in following combinations: Round Robin or One by one

Round Robin algorithm - for input endpoints [e1, e2] and queries [q1, q2, q3] creates following pairs:
(e1, q1), (e2, q2), (e1, q3), (e2, q1), (e1, q2), (e2, q3).

One by one algorithm - for input endpoints [e1, e2] and queries [q1, q2, q3] creates following pairs:
(e1, q1), (e2, q1), (e1, q2), (e2, q2), (e1, q3), (e2, q3).

Both Round Robin and One by one are supporting:

• same order of the pairs for every virtual user
• random order of the pair for every virtual user

It is also possible to enable:

• exclusive access to every combination. Only one virtual user is using combination at the single point of time
• unique access. Only one virtual user is using combination at the single point of time. One combination is used only single time during test execution

It is recommended to use JLoadBalancer to setup build-in distributers like in the example below
Or you can implement your own balancer by extending QueryPoolLoadBalancer
Example of the load balancer setup:

        //begin: following section is used for docu generation - Load balancer setup

        JTestDefinition jTestDefinition =
                JTestDefinition.builder(Id.of("td_user_scenario_example"), new UserScenarioEndpointsProvider())
                        .withInvoker(new JHttpUserScenarioInvokerProvider())
                        // Exclusive access - single scenario is executed only by one virtual user at a time. No parallel execution
                        // Random seed - different virtual users execute scenarios in different order
                        .withLoadBalancer(JLoadBalancer.builder(ROUND_ROBIN)
                                .withExclusiveAccess()
                                .withRandomSeed(1234)
                                .build())
                        .addListener(JHttpUserScenarioInvocationListener.builder()
                                .withLatencyAvgStddevAggregators()
                                .withLatencyMinMaxAggregators()
                                .withLatencyPercentileAggregators(50D, 95D, 99D)
                                .build())
                        .build();

        //end: following section is used for docu generation - Load balancer setup