The document discusses Mule's Scatter-Gather component, which sends a message concurrently to all configured routes and aggregates the responses. It can collect successful responses into a message collection, while routing failures are collected into a CompositeRoutingException. Custom aggregation strategies can be used to modify this behavior. The document provides examples of modeling Scatter-Gather in a flow and considerations for threading profiles and migrating from All routers.

1. SCATTER-GATHER COMPONENT - MULE
Presented By
Sindhu VL

2.  The routing message processor Scatter-
Gather sends a request message to multiple
targets concurrently. It collects the responses
from all routes, and aggregates them into a
single message.

3. SCATTER-GATHER BEHAVIOR AND EXCEPTIONS

4.  The Scatter-Gather router sends a message for
concurrent processing to all configured routes.
The thread executing the flow that owns the
router waits until all routes complete or time out.
 If there are no failures, Mule aggregates the
results from each of the routes into a message
collection (MessageCollection class). Failure in
one route does not stop the Scatter-Gather from
sending messages to its other configured
routes, so it is possible that many, or all routes
may fail concurrently.

5.  The Scatter-Gather router sends a message for
concurrent processing to all configured routes.
The thread executing the flow that owns the
router waits until all routes complete or time out.
 If there are no failures, Mule aggregates the
results from each of the routes into a message
collection (MessageCollection class). Failure in
one route does not stop the Scatter-Gather from
sending messages to its other configured
routes, so it is possible that many, or all routes
may fail concurrently.

6. COMPOSITEROUTINGEXCEPTION :
 The CompositeRoutingException is new to
the 3.5.0 Runtime. It extends the Mule
MessagingException to aggregate
exceptions from different routes in the
context of a single message router.
Exceptions are correlated to each route
through a sequential ID.

7.  This exception exposes two methods which
allow you to obtain the IDs of failed routes and
the exceptions returned by each route.
 The getExceptions method returns a map where
the key is an integer that identifies the index of
the failed route, and the value is the exception
itself.
 The getExceptionForRouteIndex(int) method
returns the exception of the requested route ID.

8. CUSTOMIZING AGGREGATION STRATEGIES :
 Scatter-Gather allows you to define a custom
aggregation strategy which overrides its default
aggregation strategy. Among other things,
custom gathering strategies allow you to:
 Discard message responses
 Merge message properties that originated in
different routes
 Discard failed messages without throwing an
exception
 Select only one from multiple responses

9. MODELING SCATTER-GATHER IN A FLOW :
 Add a scatter-gather element to your flow,
then, inside the dashed-line scope area of
the scatter-gather element, drag and drop
two or more message processors or
connectors, placing them parallel to one
another, as shown.

11. SCATTER-GATHER THREADING PROFILES :
 Scatter-Gather’s default threading profile is designed to
work in most scenarios, where the Scatter-Gather
component is typically configured with between three to
six routes. If the default threading profile is not best suited
for your needs, Scatter-Gather allows you to define a
custom threading profile for the component. Ultimately,
the optimum threading profile depends on each
application. For most scenarios, MuleSoft recommends
that the number of threads in Scatter-Gather should be
the result of the number of routes times the value
of maxThreadsActive for the flow where Scatter-Gather
resides.
 maxThreadsActive for Scatter-Gather = number of
routes in Scatter-GathermaxThreadsActive for flow

12. MIGRATING TO SCATTER-GATHER FROM THE ALL
MESSAGE ROUTER :
 If you are currently using All routers in your
application, you may wish to replace them
with Scatter-Gather routers. This section
details the differences you need to be aware
of when considering migration.

13. WHY MIGRATE?
 Scatter-Gather is a better option for most
cases
 migrating to Scatter-Gather now will facilitate
the transition to Mule 4

14. ThankYou!!!!!!!!!!