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• Define overall performance of POST /inventory-hierarchy/items-and-holdings;
• Find bottlenecks if possible;
• Measure KPI's for different number of instances included in request;
• Measure KPI's for different number of holdings attached per instance ID;

Overview

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Mod-inventory-storage has a new API to gather all related instances' data, i.e., items and holdings, in one call in order to eliminate making 3 separate calls to get the data. The API also allows passing in x number of instance IDs to lookup. Since teams are now starting to use this API, it's important to understand the stability of the API with respect to the module's CPU and memory usage, and also the database usage.

Summary

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1. System shows stable work and quick responses in all test;
2. No memory leaks found;
3. There is dependency a link between most used modules (see CPU) and test type. In case if it's extremely fast responses (for example for 5 holdings per instance and one instanceuser) - most used module will be mod-authtoken, otherwise in (see test 4) that will be mod-inventory-storage. Same for increasing number of instances per request.
4. DB CPU usage reach it reaches maximum at in 8-users test
5.  Fast Fast response for most high load test (test 4). To extract an instance contains > having 300+ holdings it takes (75 percentile) 373 ms . what means that for 75th percentile. Therefore getting one holding with this endpoint takes 1.2 ms.
6. No bottlenecks found. 

Version:

"okapi-3.1.2";

"mod-inventory-storage-19.4.0-SNAPSHOT.448";

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Precondition, if database free memory is less than 2000 MB, DB instance should be restarted. 

Test Runs:

Results

Summary:

During test set we've measured  general performance of new endpoint.

Test 1: 1 user, 1 instance
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Resource usage:

Most used modules: 

• Mod Authtoken;
• Okapi;
• Mod-Inventory Storage.

RDS resource usage:

RDS memory usage

As you can see, all resources shows stable behavior. During whole test Memory and CPU usage hasn't spikes or anomalies. No slow queries was found.

Test 2: 2 users, 1 instance

Resources

most Most used modules:

• mod autotoken
• okapi 
• mod inventory storage

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Comment: As you can see, 75 percentile response time for first and second test are almost the same (43ms VS 47ms) while request total number almost twice higher. That cases almost twice higher CPU usage on mod-autotoken.

Test 3: 1 user with incremental instances per iteration

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Resources

Most used module - Mod

• mod-inventory storage

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RDS memory usage

Test 4: 1 user, 1 instance with 300 holdings

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RDS CPU usage

RDS memory usage

Services CPU usage

Most used modules:

• mod-inventory storage
• okapi
• mod-authtoken

Test 5: 1 user, 50 instances

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As you can see, there is a little higher response time at the beginning of the test than at the end of it. During that time (5 minutes) 2000 http requests was executed each request contains 50 instance id's. That mean that using this endpoint we can complete 1000000 instances id's in 5 minutes.

Resources

As you can see none of modules are overloaded or has unexpected spikes.

Same situation for services memory usage

RDS :CPU usage

Using 50 instances per request RDS CPU usage reached ~20%. 

RDS Memory usage

Memory usage didn't show much usage 

Test 6: 8 users, 50 instances per request

Resources

Most used modules:

• mod-inventory storage
• okapi
• mod-authtoken

RDS CPU usage

RDS Memory usage

Test

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7: 1 user with incremental instances per request, +10 per loop

Note: maximum instances per request reached in this test - 5325 instances in one request. 

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Mod-Inventory-storage CPU usage

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Mod Inventory-storage Mem. Usage

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RDS CPU usage

RDS Memory usage

As you can see even with capacity test, resource usage show steady usage, without spikes and anomalies.  

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