The http.pipelining.max_events setting in Elasticsearch controls the maximum number of events that can be queued per HTTP connection when HTTP pipelining is enabled.
Description
- Default value: 10000
- Possible values: Any positive integer
- Recommendation: The default value is suitable for most use cases, but it can be adjusted based on specific performance requirements and available system resources.
This setting determines how many events (requests/responses) can be queued in a single HTTP connection before the connection starts to block. It helps in managing the memory usage and preventing potential out-of-memory issues when dealing with a high number of concurrent requests.
Example
To change the http.pipelining.max_events setting using the cluster settings API:
PUT _cluster/settings
{
"persistent": {
"http.pipelining.max_events": 15000
}
}
Increasing this value might be beneficial in scenarios where you have clients that send a large number of requests in quick succession and you want to improve throughput. However, be cautious as setting it too high might lead to increased memory usage.
Common Issues and Misuses
- Setting the value too high without considering the available system resources can lead to excessive memory consumption.
- Setting the value too low might result in reduced throughput and increased latency for clients that send many requests in quick succession.
Do's and Don'ts
- Do monitor your system's memory usage when adjusting this setting.
- Do consider the nature of your client applications and their request patterns when tuning this setting.
- Don't set this value arbitrarily high without testing the impact on your system.
- Don't ignore this setting if you're experiencing performance issues with HTTP pipelining enabled.
Frequently Asked Questions
Q: What is HTTP pipelining in Elasticsearch?
A: HTTP pipelining is a technique that allows multiple HTTP requests to be sent on a single TCP connection without waiting for the corresponding responses. This can improve performance by reducing latency and increasing throughput.
Q: How does the http.pipelining.max_events setting affect performance?
A: This setting controls how many events can be queued per HTTP connection. A higher value can potentially improve throughput for clients that send many requests quickly, but it also increases memory usage.
Q: Can changing http.pipelining.max_events solve all HTTP-related performance issues?
A: No, while this setting can help in certain scenarios, it's not a silver bullet. Other factors like network latency, server resources, and client behavior also play crucial roles in overall performance.
Q: Is it safe to increase http.pipelining.max_events in a production environment?
A: While it's generally safe to increase this value, it's recommended to test the changes in a staging environment first. Monitor memory usage and overall system performance to ensure the change doesn't negatively impact your cluster.
Q: How can I determine the optimal value for http.pipelining.max_events for my use case?
A: The optimal value depends on your specific use case, client behavior, and available system resources. Start with the default value and gradually increase it while monitoring performance metrics and system resource usage to find the sweet spot for your environment.
