ALTER SYSTEM MODIFY BACKEND "host1:9050" SET ("disable_query" = "true");
ALTER SYSTEM MODIFY BACKEND "host1:9050" SET ("disable_load" = "true");
ALTER SYSTEM MODIFY BACKEND "host1:9050" SET ("disable_query" = "true");
ALTER SYSTEM MODIFY BACKEND "host1:9050" SET ("disable_load" = "true");