rate-limiting

Issue Description

ConcurrentLinkedHashMap在构造二维数组时会根据CPU核心数来计算出当前数组的一维下标长度，当核数为96时，下标为128，此时单个ParameterMetric对象大小接近1M，如下图所示：

当接口调用量较大时，此处将会占用大量内存，sentinel是否有考虑过这块的内存使用，或者切成其他Cache？毕竟googlecode.concurrentlinkedhashmap作者也建议使用Caffeine了.

Tell us your environment

springbo

Sorry for not following the template. It's a straightforward question.

By enabling "WordPress-specific rules", the following codes will be added to the wordpress.conf:

# WordPress: deny general stuff
location ~* ^/(?:xmlrpc\.php|wp-links-opml\.php|wp-config\.php|wp-config-sample\.php|readme\.html|license\.txt)$ {
    deny all;
}

However, this disables xmlrpc feature, which disa

I've read the docs, and it seems you can pass through knex instances, but I didn't see if it supports SQLite3 - could you clarify please?

Issue Description

Type: bug report

Describe what happened

https://github.com/alibaba/sentinel-golang/blob/683c229b23a96c4ad07dc795da3730db8fd9d93c/exporter/metric/exporter.go#L35-L45

Since the above code (code 1) uses the init function and is executed before the following code (code 2), the app variable in code 1 is an error.

https://github.com/alibaba/sentinel-golang/b

🚀 Feature Proposal

Have an option to slow down responses instead of returning 429 errors.

Motivation

By having the option to slow down responses would deter scrapping of data from a server which would put an additional load on the server while still enabling responses for cases where user may not be actually scrapping, but just that there are many machines surfing the webpage under