-- Tags: long -- -- Test for testing various read settings. drop table if exists data_02051; create table data_02051 (key Int, value String) engine=MergeTree() order by key as select number, repeat(toString(number), 5) from numbers(1e6); {# check each local_filesystem_read_method #} {% for read_method in ['read', 'mmap', 'pread_threadpool', 'pread_fake_async'] %} {# check w/ O_DIRECT and w/o (min_bytes_to_use_direct_io) #} {% for direct_io in [0, 1] %} {# check local_filesystem_read_prefetch (just a smoke test) #} {% for prefetch in [0, 1] %} {# check read_priority (just a smoke test) #} {% for priority in [0, 1] %} {# check alignment for O_DIRECT with various max_read_buffer_size #} {% for buffer_size in [65505, 1048576] %} select count(ignore(*)) from data_02051 settings min_bytes_to_use_direct_io={{ direct_io }}, local_filesystem_read_method='{{ read_method }}', local_filesystem_read_prefetch={{ prefetch }}, read_priority={{ priority }}, max_read_buffer_size={{ buffer_size }} ; {% endfor %} {% endfor %} {% endfor %} {% endfor %} {% endfor %}