[Bug] HStore Partition Leader Changes Cause P99 Latency Jitter In The Cluster's Read And Write Operations

May 9, 2025 by ADMIN 106 views

Bug: HStore Partition Leader Changes Cause P99 Latency Jitter in the Cluster's Read and Write Operations

In this article, we will discuss a bug that affects the performance of Apache HugeGraph clusters, specifically when HStore partition leaders change. This change can cause significant P99 latency jitter in both read and write operations, impacting the overall performance and reliability of the cluster. We will delve into the details of the bug, its causes, and potential solutions to mitigate its effects.

Bug Type (问题类型)

None

Environment (环境信息)

Server Version: 1.5.0 (Apache Release Version)
Backend: HStore, SSD
OS: 32 CPUs, 128 G RAM, CentOS 7
Data Size: 1 billion vertices, 3 billion edges

Monitor

The monitoring data shows that node A experienced issues, resulting in increased latency.

Read

Read Latency

Write

Write Latency

The HugeServer log for node A is available at server.log.

TODO

The bug is caused by the frequent changes in HStore partition leaders, which can lead to the following issues:

Leader Election: When a partition leader changes, the election process can cause temporary delays in read and write operations.
Cache Invalidation: The change in partition leaders can invalidate the cache, leading to increased latency and jitter.
Rebalancing: The rebalancing process can cause temporary delays in read and write operations, especially when the cluster is under heavy load.

To mitigate the effects of this bug, we can implement the following strategies:

Reduce Leader Election Frequency: Implement a mechanism to reduce the frequency of leader elections, such as by increasing the election timeout or using a more efficient election algorithm.
Improve Cache Invalidation: Implement a more efficient cache invalidation mechanism to minimize the impact of cache invalidation on read and write operations.
Optimize Rebalancing: Optimize the rebalancing process to minimize temporary delays in read and write operations.

In conclusion, the bug affecting HStore partition leader changes can cause significant P99 latency jitter in both read and write operations, impacting the overall performance and reliability of the cluster. By understanding the causes of the bug and implementing mitigation strategies, we can reduce the impact of this bug and improve the performance of our Apache HugeGraph clusters.

Based on our analysis, we recommend the following:

Upgrade to a newer version of Apache HugeGraph: The latest versions of Apache HugeGraph may have fixed this bug or implemented mitigation strategies to its impact.
Implement the mitigation strategies: Implement the mitigation strategies outlined above to reduce the impact of this bug.
Monitor and analyze performance: Continuously monitor and analyze the performance of your cluster to identify potential issues and optimize its configuration.

By following these recommendations, we can improve the performance and reliability of our Apache HugeGraph clusters and ensure that they meet the demands of our applications.
Q&A: HStore Partition Leader Changes Cause P99 Latency Jitter in the Cluster's Read and Write Operations

In our previous article, we discussed a bug that affects the performance of Apache HugeGraph clusters, specifically when HStore partition leaders change. This change can cause significant P99 latency jitter in both read and write operations, impacting the overall performance and reliability of the cluster. In this article, we will answer some frequently asked questions (FAQs) related to this bug and provide additional information to help you understand and mitigate its effects.

A: The root cause of this bug is the frequent changes in HStore partition leaders, which can lead to leader election, cache invalidation, and rebalancing issues.

A: You can identify if your cluster is affected by this bug by monitoring the P99 latency jitter in both read and write operations. If you notice a significant increase in latency jitter, it may be related to this bug.

A: The symptoms of this bug include:

Increased P99 latency jitter in both read and write operations
Temporary delays in read and write operations
Cache invalidation and rebalancing issues

A: You can mitigate the effects of this bug by implementing the following strategies:

Reduce leader election frequency
Improve cache invalidation
Optimize rebalancing

A: Yes, upgrading to a newer version of Apache HugeGraph may fix this bug or implement mitigation strategies to its impact. We recommend checking the release notes and documentation for the latest version to see if it addresses this issue.

A: You can monitor and analyze the performance of your cluster by using tools such as:

Prometheus and Grafana for monitoring
Apache HugeGraph's built-in metrics and logging for analysis
Third-party tools for performance analysis and optimization

A: The best practices for configuring and optimizing your Apache HugeGraph cluster include:

Properly configuring the cluster's settings, such as the number of replicas and the cache size
Optimizing the cluster's configuration for your specific use case
Regularly monitoring and analyzing the cluster's performance
Implementing mitigation strategies for known issues, such as this bug

Based on our analysis, we recommend the following:

Upgrade to a newer version of Apache HugeGraph
Implement mitigation strategies
Monitor and analyze the performance of your cluster
Follow best practices for configuring and optimizing your Apache HugeGraph cluster

By following these recommendations, we can improve the performance and reliability of our Apache HugeGraph clusters and ensure that they meet the demands of our applications.