API gateway policy (Seemingly) Random delay in XML-schema validation

Products

• CA API Gateway
• API SECURITY
• CA API Gateway Precision API Monitoring Module for API Gateway (Layer 7)
• CA API Gateway Enterprise Service Manager (Layer 7)
• STARTER PACK-7
• CA Microgateway

Issue/Introduction

From time to time we see that our policies have a response time of around 5 seconds where they normally are around 500 ms. Analysis of different policies shows that the slowness always takes place at  specific places in the policy when Validating xml content. 

Environment

Release :

Component : API GATEWAY

Cause

The gateway is rebuilding the schema cache schema on a regular base based on the cluster wide property schemacache.maxAge  by default 30000 ms . If the case is large and need to pull a lot of schema's or schema;s from remote locations the rebuild could take some time and cause the policy to delay for that time when the xml validation assertion is used. 

Resolution

Increase the cluster wide property  schemacache.maxAge to a  larger value to reduce the times the cache needs to be rebuild .In this scenario client was only using static locally stored schemas , increasing the value to a day prevent any schema's invalidation during the day . If using less static schema the gateway will not refresh the schema as often and could be using a outdated schema file