Duplicate inbound QPS in some adapters | 入口QPS 重复统计问题 · alibaba/Sentinel#2931

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Description

Issue Description

我这边使用的sentinel 的版本是：1.8.1

系统规则里面有一个入口QPS 统计，并可以对它进行限流。对于我使用的版本中如果我有多个资源在API 中定义，这些定义的资源名称对某一个相同的API 的匹配结果都为TRUE的时候。全局统计(Constants.ENTRY_NODE) 将对该API 的一次请求重复计数。最终导致的结果是这一次请求被认为是多次QPS，与正常逻辑相违背。

Type: bug report or feature request 我认为它是一个BUG。我们应该将这些去重，但感觉这个问题似乎不是那么好处理。除了http 请求的API 以外，其他的资源(使用注解定义的)应该也有这种重复的问题，这种重复就更难处理了吧。参考：com.alibaba.csp.sentinel.Constants#ENTRY_NODE

关键代码片段

@Spi(order = Constants.ORDER_STATISTIC_SLOT)
public class StatisticSlot extends AbstractLinkedProcessorSlot<DefaultNode> {

    @Override
    public void entry(Context context, ResourceWrapper resourceWrapper, DefaultNode node, int count,
                      boolean prioritized, Object... args) throws Throwable {
            ... 
            if (resourceWrapper.getEntryType() == EntryType.IN) {
                // Add count for global inbound entry node for global statistics.
                Constants.ENTRY_NODE.increaseThreadNum();
                Constants.ENTRY_NODE.addPassRequest(count);
            }
            ... 
    }
}

com.alibaba.csp.sentinel.slots.system.SystemRuleManager#checkSystem


public final class SystemRuleManager {

    public static void checkSystem(ResourceWrapper resourceWrapper) throws BlockException {
        ...

        // total qps
        double currentQps = Constants.ENTRY_NODE == null ? 0.0 : Constants.ENTRY_NODE.successQps();
        if (currentQps > qps) {
            throw new SystemBlockException(resourceWrapper.getName(), "qps");
        }

        ...
    }
}

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Contributor guide

Tech stack: java
Domain: backendperformance
Issue type: bug
Difficulty: 3
Estimated time: 1-2 days
Activity status: stale
Clarity: mostly clear
Prerequisites: JavaSentinel basicsStatisticSlot
Newbie friendliness: 45
Research direction: The bug occurs in `com.alibaba.csp.sentinel.slots.statistic.StatisticSlot` where `Constants.ENTRY NODE.addPassRequest` is called for each resource that matches an incoming request, leading to duplicate QPS counts for the same request. A fix would involve deduplicating the count, perhaps by using a per request context or checking if the request has already been counted. The `com.alibaba.csp.sentinel.slots.system.SystemRuleManager` uses `Constants.ENTRY NODE.successQps()` for system rule checking, causing premature throttling. Review the issue comments for any suggested approaches and consider adding a flag in the `Context` to indicate whether the request has already been counted for the global entry node.