搜索结果: "lock"

tags: [mysql, database, performance, monitoring, production, deadlock, lock]

- raw/articles/mysql-deadlock-troubleshooting.md

SHOW PROFILE CPU, BLOCK IO, SWAPS FOR QUERY 1;

-- block io: 磁盘读写耗时

SELECT start_time, query_time, lock_time, rows_sent, rows_examined,

cat /sys/block/sda/queue/scheduler

echo mq-deadline > /sys/block/sda/queue/scheduler

ACTION=="add|change", SUBSYSTEM=="block", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="noop"

ACTION=="add|change", SUBSYSTEM=="block", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="deadline"

cat /sys/block/sda/queue/read_ahead_kb

cidr_block = "10.0.0.0/16"

cidr_block = var.vpc_cidr

cidr_block = "10.0.1.0/24"

dynamodb_table = "terraform-locks"

cidr_block = "10.0.0.0/16"

SETNX lock:order:123 "locked" # 获取锁

DEL lock:order:123 # 释放锁 — 如果业务逻辑崩溃，锁永远不释放

SET lock:order:123 NX EX 30 # 30秒自动过期

### 47. inode 与 block

- **inode**: 存储文件元数据（权限、大小、时间、block 位置）

- **block**: 存储文件实际数据

block - 手动封禁指定 IP

unblock - 解封指定 IP

脚本通过解析系统 SSH 认证日志（`/var/log/auth.log` 或 `/var/log/secure`），使用 `grep "Failed password"` 提取失败登录 IP，按出现次数排序。超过 `MAX_ATTEMPTS` 阈值的 IP 自动通过 `iptables -I INPUT -s -j DROP` 封禁（或 `ufw deny from `）。封禁记录写入 `/tmp/blocked_ips.db`，含封禁时间、解封时间、原因，供自动解封和查询使用。

- deadlock: 死锁分析

- lock: 锁机制详解

# Query_time: 4.718782 Lock_time: 0.000162 Rows_sent: 20 Rows_examined: 980000

# Query_time: 0.023401 Lock_time: 0.000108 Rows_sent: 20 Rows_examined: 56218

FROM information_schema.INNODB_LOCK_WAITS w

JOIN information_schema.INNODB_TRX b ON w.blocking_trx_id = b.trx_id

└── lock/ # 锁文件

/sys/block/ # 块设备

cat /sys/block/sda/queue/scheduler

echo mq-deadline > /sys/block/sda/queue/scheduler

Authentication refused: User matches Match block with restriction

Authentication refused: User matches Match block with restriction

- Created raw: raw/articles/mysql-deadlock-troubleshooting.md

- B类 9 页：block 格式 sources + 尾部重复 → 仅保留 frontmatter sources

SET GLOBAL slave_parallel_type = 'LOGICAL_CLOCK';

COPY package.json package-lock.json ./

bpftrace -e 'tracepoint:block:block_rq_complete {

| **Buffer** | 块设备元数据缓存（superblock、inode bitmap 等），加速磁盘元数据操作 | `Buffers` | 内存紧张时可回收 |

auth required pam_tally2.so deny=3 unlock_time=600 even_deny_root root_unlock_time=300

content_by_lua_block {

- 每个 server block 只有一个文件，不跨文件碎片化配置