Asynchronous I/O Read Optimization

Purpose

Asynchronous I/O read allows a program to continue to execute other tasks immediately after initiating an I/O operation. This prevents threads from being idle when waiting for I/O completion, improving CPU utilization and overall throughput.

Procedure

1. Log in to ClickHouse on the client.

   1	clickhouse -m -n

2. Set asynchronous I/O read.

   1 2	set preferred_block_size_bytes=2000000; set allow_asynchronous_read_from_io_pool_for_merge_tree=true;