集群分片信息可以使用：select cluster,shard_num,replica_num,host_name from system.clusters;查询获取。
select * from system.merges;
selete * system.mutations; 突变，修改表结构的突变操作，alter
select * from system.replication_queue; 同步队列
安全集群同时开启 8123/8443 端口：SSL_NONESSL_BOTH_ENABLE
查询引擎和数据量：
select database, name, engine, total_rows from system.tables where database!=’system’
clickhouse 统计表数据量大小：
select is_temporary, metadata_modification_time, create_table_query,
engine_full, total_rows, total_bytes, lifetime_rows, lifetime_bytes, engine, data_paths,
metadata_path, uuid, storage_policy from system.tables where database = ‘%s’ and name = ‘%s’;
查询参数配置：
show settings like ‘max_memory_usage’;
SELECT *
FROM system.settings
WHERE name IN (‘max_execution_time’, ‘receive_timeout’)
