ClickHouse清理磁盘空间

数据库本身的日志占多数，早期的日志未处理，后面的都设置了30天自动清理的。

操作涉及的一些SQL如下：

SELECT
sum(rows) AS total_rows,
formatReadableSize(sum(data_uncompressed_bytes)) AS before_compress,
formatReadableSize(sum(data_compressed_bytes)) AS after_compress,
round((sum(data_compressed_bytes)/sum(data_uncompressed_bytes))* 100,0) AS compress_rate,
table AS tbname
FROM system.parts where database = 'system' group by table

SELECT * FROM system.parts where database = 'system' and table= 'query_log_0'

select count(*) from system.query_log_0;

ALTER table `system`.query_log_0 DELETE where event_date is not null;

ALTER table `system`.trace_log_0 DELETE where event_date is not null;