ElasticSearch之Analyze index disk usage API

本API用于分析、统计指定index当前占用的存储空间。
考虑到本特性目前仍然处于预览状态，因此使用方法、参数等可能会发生变化，或者未来也许会被删除。
本API暂时不建议在生产系统中使用。

命令样例如下：

curl -X POST "https://localhost:9200/testindex_001/_disk_usage?run_expensive_tasks=true&pretty" --cacert $ES_HOME/config/certs/http_ca.crt -u "elastic:ohCxPH=QBE+s5=*lo7F9"

执行结果的样例，如下：

{"_shards" : {"total" : 1,"successful" : 1,"failed" : 0},"testindex_001" : {"store_size" : "249b","store_size_in_bytes" : 249,"all_fields" : {"total" : "0b","total_in_bytes" : 0,"inverted_index" : {"total" : "0b","total_in_bytes" : 0},"stored_fields" : "0b","stored_fields_in_bytes" : 0,"doc_values" : "0b","doc_values_in_bytes" : 0,"points" : "0b","points_in_bytes" : 0,"norms" : "0b","norms_in_bytes" : 0,"term_vectors" : "0b","term_vectors_in_bytes" : 0,"knn_vectors" : "0b","knn_vectors_in_bytes" : 0},"fields" : { }}
}

方法参数
ignore_unavailable，默认值为false。

true，本操作执行时跳过失效或者不可用的index。

false，本操作执行时，遇到失效或者不可用的index，则报错，样例如下：

{"error" : {"root_cause" : [{"type" : "index_not_found_exception","reason" : "no such index [testindex_002]","resource.type" : "index_or_alias","resource.id" : "testindex_002","index_uuid" : "_na_","index" : "testindex_002"}],"type" : "index_not_found_exception","reason" : "no such index [testindex_002]","resource.type" : "index_or_alias","resource.id" : "testindex_002","index_uuid" : "_na_","index" : "testindex_002"},"status" : 404
}

wait_for_active_shards，默认值为1，即主副本。
执行本操作时，必须处于可用状态的副本的数量。

run_expensive_tasks，默认值为false。
计算空间占用率的操作需要消耗大量的资源。

true，执行运算操作。

false，提示错误，样例如下：

{"error" : {"root_cause" : [{"type" : "illegal_argument_exception","reason" : "analyzing the disk usage of an index is expensive and resource-intensive, the parameter [run_expensive_tasks] must be set to [true] in order for the task to be performed."}],"type" : "illegal_argument_exception","reason" : "analyzing the disk usage of an index is expensive and resource-intensive, the parameter [run_expensive_tasks] must be set to [true] in order for the task to be performed."},"status" : 400
}