I am using VPS with Ubuntu 20.04 and getting error after entering clickhouse-client: Connecting to localhost:9000 as user default. Code: 210. DB::NetException: Connection refused (localhost:9000). (NETWORK_ERROR)
Just installed clickhouse so config file was not modified. Checked also lines like <listen_host>::</listen_host>, they are all commented. Tried to uncomment line with ::, didn't help, commented back.
Entered tail -64 /var/log/clickhouse-server/clickhouse-server.err.log
[ 23041 ] {} Application: Child process was terminated by signal 9 (KILL). If it is not done by 'forcestop' command or manually, the possible cause is OOM Killer (see 'dmesg' and look at the '/var/log/kern.log' for the details).
dmesg
Out of memory: Killed process 23960 (clickhouse-serv) total-vm:1451144kB, anon-rss:44780kB, file-rss:282976kB, shmem-rss:0kB, UID:998 pgtables:1188kB oom_score_adj:0
So tried to increase ratio from 0.9 by default up to 8, didn't help <max_server_memory_usage_to_ram_ratio>2</max_server_memory_usage_to_ram_ratio>
And finally it seems like 512mb of RAM on vps is extremely low for clickhouse, however is there any way at least to start client and test small database?
https://clickhouse.com/docs/en/operations/tips#ram
You need to have 4GB SWAP.
You need to change <mlock_executable>true</mlock_executable> to false in config.xml