filesystem_read_prefetches_log

Description

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.

hostname (LowCardinality(String))
clickhouse_version (LowCardinality(String)) — Version of the ClickHouse server that produced the row.
system_processor (LowCardinality(String)) — CPU architecture of the ClickHouse server that produced the row.
event_date (Date)
event_time (DateTime)
query_id (String)
path (String)
offset (UInt64)
size (Int64)
prefetch_submit_time (DateTime64(6))
priority (Int64)
prefetch_execution_start_time (DateTime64(6))
prefetch_execution_end_time (DateTime64(6))
prefetch_execution_time_us (UInt64)
state (String)
thread_id (UInt64)
reader_id (String)