> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-fbfa8bee.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> 包含从以远程文件系统为底层存储的 MergeTree 表读取数据时执行的所有预取操作的历史记录。
可随时安全地对该表执行 truncate 或 drop 操作。

# system.filesystem_read_prefetches_log

包含从以远程文件系统为底层存储的 MergeTree 表读取数据时执行的所有预取操作的历史记录。

可随时安全地对该表执行 truncate 或 drop 操作。

列：

* `hostname` ([LowCardinality(String)](/zh/reference/data-types/lowcardinality))
* `event_date` ([Date](/zh/reference/data-types/date))
* `event_time` ([DateTime](/zh/reference/data-types/datetime))
* `query_id` ([String](/zh/reference/data-types/string))
* `path` ([String](/zh/reference/data-types/string))
* `offset` ([UInt64](/zh/reference/data-types/int-uint))
* `size` ([Int64](/zh/reference/data-types/int-uint))
* `prefetch_submit_time` ([DateTime64(6)](/zh/reference/data-types/datetime64))
* `priority` ([Int64](/zh/reference/data-types/int-uint))
* `prefetch_execution_start_time` ([DateTime64(6)](/zh/reference/data-types/datetime64))
* `prefetch_execution_end_time` ([DateTime64(6)](/zh/reference/data-types/datetime64))
* `prefetch_execution_time_us` ([UInt64](/zh/reference/data-types/int-uint))
* `state` ([String](/zh/reference/data-types/string))
* `thread_id` ([UInt64](/zh/reference/data-types/int-uint))
* `reader_id` ([String](/zh/reference/data-types/string))