Kong LUA Shared Dictionary Usage Test

In Kong API Gateway, LUA Shared Dictionary Usage refers to the in-memory storage used by Kong’s Nginx-based runtime to store temporary data like rate limits, caching, and session data. Efficient usage ensures fast performance and low latency. Overuse or exhaustion can lead to errors and degraded API performance.

Monitoring Kong API LUA Shared Dictionary Usage helps administrators ensure optimal memory utilization, prevent dictionary overflows, and maintain high performance. It enables early detection of memory pressure, supports efficient plugin behavior, and helps avoid runtime errors that could disrupt API traffic, ensuring stable and reliable API gateway operations.

This test reports the key metrics like Allocated, used and percentage used memory, these metrics provide actionable insights to admins to identify and fix any issues before any performance degradation.

Target of the test : A Kong API Gateway

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the target Kong API Server being monitored.

Configurable parameters for the test

Parameter	Description
Test Period	How often should the test be executed.
Host	The IP address of the host for which this test is to be configured.
Port	Specify the port at which the specified Host listens. By default, this is 8001.
SSL Enabled	If the Kong API Gateway uses the HTTPS protocol, set the SSL ENABLED test parameter to Yes. By default, this parameter is set to No.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Allocated memory	Indicates the total memory allocated for this Kong API Gateway in NGINX.	MB	The total size of the shared dictionary allocated in NGINX. This represents the maximum memory available for caching, plugin state, counters, etc.
Used memory	Indicates the memory currently used from the allocated memory for this Kong API Gateway in NGINX.	MB	The amount of memory currently in use within the shared dictionary. This includes cached data, counters, plugin states, and other runtime data.
Percentage memory used	Indicates the percentage of allocated memory currently in use by Kong API Gateway.	Percentage	Represents how much of the shared dictionary’s allocated memory is currently in use. A higher percentage indicates the dictionary is nearing full capacity, which may lead to evictions or failures to store new data.