Question
Answer and Explanation
Yes, there are several ways to tune time-related settings in the FIWARE Orion Context Broker. These settings primarily deal with how the broker handles expirations, caching, and internal operations. Here’s a breakdown of the key areas and how you can adjust them:
1. Subscription Expiration:
- Purpose: Subscriptions in Orion have an expiration time. After this time, the subscription will be removed unless it's renewed.
- How to Tune: You can set the expiration time when creating the subscription. This is done through the `expires` field in the subscription payload. The time format is typically ISO 8601.
- Example:
{
"subject": { ... },
"notification": { ... },
"expires": "2024-08-20T10:00:00.00Z"
}
- Note: There isn't a global Orion setting for subscription expirations; it's handled per subscription.
2. Caching Time-to-Live (TTL):
- Purpose: Orion uses an internal cache to store recently accessed context data to optimize performance. The TTL determines how long data stays valid in the cache.
- How to Tune: The caching TTL can be configured using command-line options when starting the Orion broker. Specific options include -cacheMaxAge and -cacheMinAge, allowing you to define the maximum and minimum cache lifetimes in seconds. Default values vary, but are typically a few seconds to a few minutes. The -defaultCacheMaxAge determines the default value when cache settings are not provided at the entity level.
- Example:
orion -cacheMaxAge 10 -cacheMinAge 1 -defaultCacheMaxAge 15
- Note: Adjust these carefully as this impacts performance and consistency of data.
3. Internal Timeout Settings:
- Purpose: Orion has internal timeout settings that govern the maximum time to complete operations such as database queries or internal services.
- How to Tune: While there aren't direct command-line switches for every timeout scenario, you may find configurations related to database connection timeouts. The main way to adjust this is through the environment variables like ORION_MONGODB_CONNECT_TIMEOUT_MS and ORION_MONGO_SOCKET_TIMEOUT_MS for adjusting database timeouts. There's also ORION_HTTP_REQUEST_TIMEOUT_MS for HTTP requests and ORION_BATCH_REQUEST_TIMEOUT_MS for batch operations.
- Example:
export ORION_MONGODB_CONNECT_TIMEOUT_MS=5000
export ORION_MONGO_SOCKET_TIMEOUT_MS=10000
export ORION_HTTP_REQUEST_TIMEOUT_MS=7000
- Note: These should be configured cautiously, as incorrect timeouts can lead to connection issues or slow responses.
4. Operation Timeouts:
- Purpose: You can control how long Orion waits for certain operations like updates or queries before returning an error.
- How to Tune: Some operations can be configured on a per-request basis using headers like Fiware-Request-Timeout, specified in milliseconds.
- Example: You would add this header in an HTTP request to Orion.
5. Advanced Settings:
- Purpose: Some time-related settings may be hidden within the source code or configurable through configuration files if you are running a custom setup of Orion.
- How to Tune: This typically requires deeper knowledge of the Orion codebase and deployment methods. This is not a common or recommended way of configuring Orion.
In Summary, tuning time settings of Orion involves a combination of settings:
- Subscription expirations are set per subscription.
- Caching is configured with command-line arguments.
- Internal timeouts are adjusted via environment variables and request headers.
Carefully configure these settings based on the specific needs of your application and environment. Always monitor performance and error logs when making adjustments. Check the latest Orion documentation for more detailed information regarding these and any other potential configurations.