如何找到 Redis 中的较大的 Key？

2024-11-30 by dongnan

问题描述

Redis 服务报警，使用 MEMORY STATS 查看内存统计信息：

MEMORY STATS

结果如下

*52
$14
peak.allocated
:1762869432
$15
total.allocated
:1750957064
$17
省略...
keys.count
:2445
$18
keys.bytes-per-key
:713143
省略...

内存使用情况：

峰值分配内存：1762869432 字节。
当前分配内存：1750957064 字节。
数据集内存占用：约 1.71 GB，占总内存的 98.05%。

Key 分布：

总 Key 数：2445。
平均每 Key 占用内存：713143 字节。

内存碎片：

总碎片率：1.0176，有轻微的内存碎片。

环境描述

OS: Ubuntu Server 20.04 LTS
redis-cli: 5.0.7

redis-cli

redis-cli 是 redis 命令行下的接口工具，用于与 redis 服务端交互，常用命令参考这里。

找到 Redis 中的较大的 Key

使用 redis-cli --bigkeys 这个工具会扫描所有 Key，统计每种类型的最大 Key：

redis-cli -h r-8vb7xxxro.redis.xxx.rds.aliyuncs.com -a xxxx --bigkeys

结果如下：

# Scanning the entire keyspace to find biggest keys as well as
# average sizes per key type.  You can use -i 0.1 to sleep 0.1 sec
# per 100 SCAN commands (not usually needed).

[00.00%] Biggest string found so far 'hdxxxk:ORDER_CONCENTRATE-C2409180001' with 1 bytes
[00.41%] Biggest zset   found so far '20xxx_iplog' with 1 members
[00.41%] Biggest string found so far 'sys_dict:stock_change_type' with 641 bytes
[00.85%] Biggest string found so far 'sys_xxt:affairs_status' with 681 bytes
[00.85%] Biggest list   found so far 'sigxxx_to_access:client:kongtiantian' with 1 items
[03.46%] Biggest zset   found so far '2021-11-03_iplog' with 2 members
[07.24%] Biggest string found so far 'shiro:cache:com.alsace.framework.common.shiro.JwtRealm.authenticationCache:eyJsAxxx8DqWpYg' with 766 bytes
[11.47%] Biggest string found so far 'sys_dict:xxx' with 1610 bytes
[47.84%] Biggest zset   found so far '2020-07-02_iplog' with 4 members
[48.70%] Biggest string found so far 'sys_dict:oxxxision' with 3244 bytes
[94.30%] Biggest list   found so far 'QIxxx_Log' with 1222638 items

-------- summary -------

Sampled 2457 keys in the keyspace!
Total key length in bytes is 106710 (avg len 43.43)

Biggest string found 'sys_dict:overdue_decision' has 3244 bytes
Biggest   list found 'QIMINGXING_request_Log' has 1222638 items
Biggest   zset found '2020-07-02_iplog' has 4 members

2405 strings with 44266 bytes (97.88% of keys, avg size 18.41)
5 lists with 1222642 items (00.20% of keys, avg size 244528.40)
0 sets with 0 members (00.00% of keys, avg size 0.00)
0 hashs with 0 fields (00.00% of keys, avg size 0.00)
47 zsets with 67 members (01.91% of keys, avg size 1.43)
0 streams with 0 entries (00.00% of keys, avg size 0.00)

清理 redis 所有的 key (可选)

注意：以下两个命令会立即删除数据，且无法恢复，请确保操作前备份重要数据。

清空当前数据库（默认 DB 0）：

redis-cli FLUSHDB

清空所有数据库中的 Key（适用于多个数据库）：

redis-cli FLUSHALL

参考

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