Clickhouse For CentOs¶
JDK ¶
Using JDK 11 as well as enabling G1 garbage collector is recommended. Comparing to JDK 8, the performance of handling jobs under multi-threads will be improved more than 30%.
Clickhouse¶
1. Download ¶
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2. Install¶
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3. Memory Settings¶
We will need to limit the clickhouse service If the client server has a memory less than 32GB.
clickhouse memory settings¶
In /etc/clickhouse-server/config.xml
set max_server_memory_usage_to_ram_ratio
to 0.125 so that 32G*0.125 will be 4G

Update /etc/clickhouse-server/users.xml
and set max_memory_usage
to 4000000000, max_bytes_before_external_group_by
to 2000000000. You may need to create max_bytes_before_external_group_by
if it isn't present.

Restart the Clickhouse service: sudo /etc/init.d/clickhouse-server restart
Sqlservice memory settings¶
With this config, the Simple mode will use 22G memory and the Rugular mode will be in 18G memory.
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4. Set Clickhouse default password¶
Set Clickhouse password to sqlflow@gudu
If mistakenly set to another password, you will need:
- delete
/etc/clickhouse-server/users.d/default-password.xml
- update
/etc/clickhouse-server/users.xml
, set password to sqlflow@gudu - restart Clickhouse,
sudo /etc/init.d/clickhouse-server restart
5. Init Clickhouse¶
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If you got

Then you might need to check for your OS version and the Clickhouse is not properly installed. Check Ubuntu/Debian/RHEL Installation.
If your clickhouse is properly installed but you still got errors, please check /var/log/clickhouse-sever
for error logs.
6. Start SQLFlow¶
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