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

> Contains a history of all prefetches done during reading from MergeTree tables backed by a remote filesystem.
It is safe to truncate or drop this table at any time.

# system.filesystem_read_prefetches_log

<h2 id="description">
  Description
</h2>

Contains a history of all prefetches done during reading from MergeTree tables backed by a remote filesystem.

It is safe to truncate or drop this table at any time.

<h2 id="columns">
  Columns
</h2>

* `hostname` ([LowCardinality(String)](/reference/data-types/lowcardinality))
* `clickhouse_version` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — Version of the ClickHouse server that produced the row.
* `system_processor` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — CPU architecture of the ClickHouse server that produced the row.
* `event_date` ([Date](/reference/data-types/date))
* `event_time` ([DateTime](/reference/data-types/datetime))
* `query_id` ([String](/reference/data-types/string))
* `path` ([String](/reference/data-types/string))
* `offset` ([UInt64](/reference/data-types/int-uint))
* `size` ([Int64](/reference/data-types/int-uint))
* `prefetch_submit_time` ([DateTime64(6)](/reference/data-types/datetime64))
* `priority` ([Int64](/reference/data-types/int-uint))
* `prefetch_execution_start_time` ([DateTime64(6)](/reference/data-types/datetime64))
* `prefetch_execution_end_time` ([DateTime64(6)](/reference/data-types/datetime64))
* `prefetch_execution_time_us` ([UInt64](/reference/data-types/int-uint))
* `state` ([String](/reference/data-types/string))
* `thread_id` ([UInt64](/reference/data-types/int-uint))
* `reader_id` ([String](/reference/data-types/string))