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Increase Pipeline Throughput By Parallelizing Service Calls

dwhite
Employee
Employee

Many times when designing a pipeline for a use case one may need to make a call to an external service (REST/SOAP). In SnapLogic REST and SOAP snaps operate serially, meaning they can only process one document at a time. Some service calls may take an extended period of time to come back, so this will essentially block oneโ€™s pipeline execution until a response is received. This may be an acceptable for a pipeline with little volume, but if one is processing thousands of documents or more and each call takes a few seconds to complete, it can rack up quite the runtime.

To get around this, one can distribute the incoming documents over a number of outputs and add more snaps to make service calls.

To evenly distribute incoming documents across multiple outputs, one can use the router snap in โ€œautoroutingโ€ mode. What this will do is round-robin incoming documents over the number of given outputs. To setup, drag a router snap onto oneโ€™s pipeline, add the desired number of output views, and leave the expressions correlating to those output views blank.

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After that is setup, copy oneโ€™s snap making the service call and add one to each of the router outputs.

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Union the REST outputs to recombine the streams, and then reconnect the remaining pipeline logic.

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Thats it!

If your service calls block even a few seconds and one is making a large number of calls, this should decrease the runtime a bit. The exact amount of parallelism to use will be a factor of the use case and the service endpoint. Iโ€™ve found that two calls has worked best most of the time, only on extreme volume was an advantage gained by going to 3 or more.

6 REPLIES 6

tstack
Former Employee

Another approach would be to put the parts of the pipeline you wish to parallelize in a child pipeline that is called with the Pipeline Execute snap. Using a child pipeline will save you the trouble of having to maintain copies of the snaps and make it easier to test different concurrency levels since itโ€™s just a matter of changing the โ€˜Pool Sizeโ€™ property.

walkerline117
Contributor

So is this the same as having a sub-pipeline and tune the pool size of the Pipeline execute?

This is in addition to this.

So if you have 100 documents, and only one pipeline execute with a pool size of 10, then 10 are distributed for each instantiation of execution.

In this case net instantiations are only 10.

Now with the same amount of documents, you have 2 routes each calling pipeline execute with a pool size of 10 then 50 are distributed in 2 routes and then 5 run across each instantiation of execution.

In this case net instantiations are now 20.

Hope that makes sense.

So then why I have such duplicate in terms of snap and why not just do one pipeline execute with pool size of 20?