clickhouse config on low memory situations

[T100D]

This could be something for people running clickhouse-server in an environment with less than 32GB and a smaller setup for testing it can be helpful to tune clickhouse to this situation so it does not run out of memory.

adjust the following in: /etc/clickhouse-server/config.xml

<logger>
<level>information</level>

<!-- <mark_cache_size>5368709120</mark_cache_size> -->
<mark_cache_size>2684354560</mark_cache_size>

<max_server_memory_usage_to_ram_ratio>0.9</max_server_memory_usage_to_ram_ratio>
<max_server_memory_usage_to_ram_ratio>0.7</max_server_memory_usage_to_ram_ratio>

Second, now there is retention handeling that looks at disk space, the extensive logging can be problemetic for coroot. I have two situations where this led from having data for one hour to one day. It can easily contain 20GB data or more.

Logging to the database can be disabled by creating a file:
/etc/clickhouse-server/config.d/z_log_disable.xml

with the following contents:

<?xml version="1.0"?>
<clickhouse>
    <asynchronous_metric_log remove="1"/>
    <metric_log remove="1"/>
    <latency_log remove="1"/>
    <query_thread_log remove="1" />
    <query_log remove="1" />
    <query_views_log remove="1" />
    <part_log remove="1"/>
    <session_log remove="1"/>
    <text_log remove="1" />
    <trace_log remove="1"/>
    <crash_log remove="1"/>
    <opentelemetry_span_log remove="1"/>
    <zookeeper_log remove="1"/>
</clickhouse>