Questions about `UnHealthy Connection Expel Task` connection select

[YunWZ]

Is your feature request related to a problem? Please describe. UnHealthy Connection Expel Task will evict connections that exceed the limited count.

The selection priority of the connection set is:

1. exceed the count per client ip or app；
2. random connection set.

the code show as below(ConnectionManager.java):

                //1. calculate expel count  of ip.
                for (Map.Entry<String, Connection> entry : entries) {

                    Connection client = entry.getValue();
                    String appName = client.getMetaInfo().getAppName();
                    String clientIp = client.getMetaInfo().getClientIp();
                    if (client.getMetaInfo().isSdkSource() && !expelForIp.containsKey(clientIp)) {
                        //get limit for current ip.
                        int countLimitOfIp = connectionLimitRule.getCountLimitOfIp(clientIp);
                        if (countLimitOfIp < 0) {
                            int countLimitOfApp = connectionLimitRule.getCountLimitOfApp(appName);
                            countLimitOfIp = countLimitOfApp < 0 ? countLimitOfIp : countLimitOfApp;
                        }
                        if (countLimitOfIp < 0) {
                            countLimitOfIp = connectionLimitRule.getCountLimitPerClientIpDefault();
                        }

                        if (countLimitOfIp >= 0 && connectionForClientIp.containsKey(clientIp)) {
                            AtomicInteger currentCountIp = connectionForClientIp.get(clientIp);
                            if (currentCountIp != null && currentCountIp.get() > countLimitOfIp) {
                                expelForIp.put(clientIp, new AtomicInteger(currentCountIp.get() - countLimitOfIp));
                            }
                        }
                    }
                }

                Set<String> outDatedConnections = new HashSet<>();
                long now = System.currentTimeMillis();
                //2.get expel connection for ip limit.
                for (Map.Entry<String, Connection> entry : entries) {
                    Connection client = entry.getValue();
                    String clientIp = client.getMetaInfo().getClientIp();
                    AtomicInteger integer = expelForIp.get(clientIp);
                    if (integer != null && integer.intValue() > 0) {
                        integer.decrementAndGet();
                        expelClient.add(client.getMetaInfo().getConnectionId());
                        expelCount--;
                    } else if (now - client.getMetaInfo().getLastActiveTime() >= KEEP_ALIVE_TIME) {
                        outDatedConnections.add(client.getMetaInfo().getConnectionId());
                    }

                }

                //3. if total count is still over limit.
                if (expelCount > 0) {
                    for (Map.Entry<String, Connection> entry : entries) {
                        Connection client = entry.getValue();
                        if (!expelForIp.containsKey(client.getMetaInfo().clientIp) && client.getMetaInfo()
                                .isSdkSource() && expelCount > 0) {
                            expelClient.add(client.getMetaInfo().getConnectionId());
                            expelCount--;
                            outDatedConnections.remove(client.getMetaInfo().getConnectionId());
                        }
                    }
                }

The question is: why not evict the outdated connections before random connections?

Describe the solution you'd like I think it would be better to do it this way：

1. evict connections that exceed the count per client ip or app；
2. evict connections that exceed the outdated connctions;
3. random eviction from all connections

For outdated connections, there is a high probability that the connection has been disconnected。

[shiyiyue1102]

Yes, you are right, if the total count is no longer exceed the limit rule after active detection, we should not evict any connections.

[leopardrota]

So, why not evict the outdated connections before random connections? The solution the author would like should be implemented or not?

[stale[bot]]

Thanks for your feedback and contribution. But the issue/pull request has not had recent activity more than 180 days. This issue/pull request will be closed if no further activity occurs 7 days later. We may solve this issue in new version. So can you upgrade to newest version and retry? If there are still issues or want to contribute again. Please create new issue or pull request again.