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Clickhouse在Ubuntu进行查询时报内存不够错误

description

执行查询时, clickhouse报如下内存错误:

code: 241, message: Memory limit (total) exceeded: would use 67.77 GiB (attempt to allocate chunk of 4223432 bytes), current RSS 2.28 GiB, maximum: 56.15 GiB. OvercommitTracker decision: Query was selected to stop by OvercommitTracker.: While executing MergeTreeSelect(pool: ReadPool, algorithm: Thread): Could not process SQL results.

1. 设置内存过度提交​

sudo sysctl -w vm.overcommit_memory=1
echo 'vm.overcommit_memory=1' | sudo tee -a /etc/sysctl.conf
# 含义:
# 0: 内核会根据一定算法判断是否允许分配（推荐）
# 1: 允许分配超过物理内存总量（对 ClickHouse 更宽松)
# 2: 严格限制(❌ 不推荐)

2. 调整 Swap 策略(减少磁盘交换)​

sudo sysctl -w vm.swappiness=10
echo 'vm.swappiness=10' | sudo tee -a /etc/sysctl.conf

3. 关闭 Transparent Huge Pages(THP)​

cat /sys/kernel/mm/transparent_hugepage/enabled

# 如果不是 [never]，建议关闭：
sudo vim /etc/default/grub
# 修改 GRUB_CMDLINE_LINUX_DEFAULT，添加：
GRUB_CMDLINE_LINUX_DEFAULT="... transparent_hugepage=never"
sudo update-grub
sudo reboot