vacuum：死元组和 autovacuum

哪些表死元组多、autovacuum 会不会去清、现在有没有 vacuum 在跑。

采集于 2026-10-07（UTC+08），本地 KingbaseES V008R006C009B0014 主节点和备节点，数据库 test。工具是 Go 版源码提交 96c874f 编译的 ~/kbdiag（linux/amd64 静态二进制）。这是测试环境实测，不代表生产环境验收。WARN 的例子由注入脚本造出来：它建了表 public.kbdiag_inj_dead，设为 autovacuum_enabled=off，插入 10000 行再删掉 5000 行，所以表里有 5000 个没人会清的死元组。数值只属于本次采样。

用法

kbdiag vacuum [--limit N] [--json]

参数	作用
`--limit N`	最多显示 N 张表；默认 20，`0` 表示全部
`--json`	输出 JSON

连接参数和 sessions 相同。--limit 只裁表的列表，判定覆盖所有表。vacuum 看的是当前连接的库（默认 test）。

主库，正常

~/kbdiag vacuum
echo EXIT_CODE=$?

vacuum  OK  (KingbaseES V008R006C009B0014, primary, system@local, 2026-10-07T17:20:54+08:00)

settings
  autovacuum    on  (3 workers, naptime 1m 0s)
  track_counts  on
  threshold     50 + 0.2 x reltuples

running: 0

tables in test: 98, most dead tuples first
  table                             dead  live  threshold  due  autovacuum  last autovacuum  last vacuum
  sysmac.sysmac_policy              0     0     50.2       -    on          never            never
  sysmac.sysmac_level               0     0     50.8       -    on          never            never
  sysmac.sysmac_compartment         0     0     50         -    on          never            never
  sysmac.sysmac_label               0     0     50.8       -    on          never            never
  sysmac.sysmac_policy_enforcement  0     0     50         -    on          never            never
  sysmac.sysmac_user                0     0     50         -    on          never            never
  sysmac.sysmac_obj                 0     0     50         -    on          never            never
  sysmac.sysmac_column_label        0     0     50         -    on          never            never
  sys_hm.check_type                 0     0     50.4       -    on          never            never
  sys_hm.hm_run_t                   0     0     50         -    on          never            never
  sys_hm.check_param                0     0     50.2       -    on          never            never
  sys.dual                          0     0     50.2       -    on          never            never
  sys_catalog._kingbase_loginfo     0     0     50         -    on          never            never
  public.t1                         0     0     50         -    on          never            never
  public.t_perf_test                0     0     20050      -    on          never            never
  kdb_schedule.kdb_jobagent         0     0     50         -    on          never            never
  kdb_schedule.kdb_jobclass         0     0     50         -    on          never            never
  kdb_schedule.kdb_action           0     0     50         -    on          never            never
  kdb_schedule.kdb_schedule         0     0     50         -    on          never            never
  kdb_schedule.kdb_schedule_job     0     0     50         -    on          never            never
  ... 78 more not shown (--limit 0 shows all)
EXIT_CODE=0

settings 显示 autovacuum 和 track_counts 开没开、worker 数和 naptime，以及触发线公式（threshold 加上比例系数乘 reltuples）。
running 列出正在跑的 VACUUM 和进度（进度细节见 progress）。这里没有。
tables 按死元组数排序。threshold 是这张表的 autovacuum 触发线，算法和服务器一样（用 float4，表上的 reloptions 会覆盖全局值）。due 表示死元组是否过了这条线。autovacuum 是这张表自己的开关。
列表按死元组数排序，最上面的行都是 0，所以没有表过线。每张表的 last autovacuum never 只说明统计重置以来 autovacuum 没轮到过它们。

备库

~/kbdiag vacuum
echo EXIT_CODE=$?

vacuum  OK  (KingbaseES V008R006C009B0014, standby, system@local, 2026-10-07T17:21:01+08:00)

settings
  autovacuum    on  (3 workers, naptime 1m 0s)
  track_counts  on
  threshold     50 + 0.2 x reltuples

running: not_applicable  (standby: autovacuum does not run here; run on the primary)

tables in test: not_applicable  (standby: table statistics are local to each node and stay 0 here; run on the primary)
EXIT_CODE=0

表统计是节点本地的，备库上全是 0，autovacuum 也不在备库上跑，所以 running 和 tables 是 not_applicable，设置照样展示。要看 vacuum 到主库上跑。

没人会清的表

~/kbdiag vacuum
echo EXIT_CODE=$?

vacuum  WARN  (KingbaseES V008R006C009B0014, primary, system@local, 2026-10-07T17:21:12+08:00)

[WARN] vacuum.table_disabled  table public.kbdiag_inj_dead has 5000 dead tuples, past its autovacuum threshold 2050, but autovacuum is off for it (autovacuum_enabled=off): nothing will clean it
  fix: VACUUM public.kbdiag_inj_dead  # connected to database test; turn autovacuum back on with ALTER TABLE ... RESET (autovacuum_enabled) unless it was turned off on purpose
  verify: kbdiag txn  # if dead tuples remain after VACUUM: the oldest transaction holding back the horizon
  verify: kbdiag slots  # or a replication slot's xmin

settings
  autovacuum    on  (3 workers, naptime 1m 0s)
  track_counts  on
  threshold     50 + 0.2 x reltuples

running: 0

tables in test: 99, most dead tuples first
  table                             dead  live  threshold  due  autovacuum  last autovacuum  last vacuum
  public.kbdiag_inj_dead            5000  5000  2050       yes  off         never            never
  sysmac.sysmac_policy              0     0     50.2       -    on          never            never
  sysmac.sysmac_level               0     0     50.8       -    on          never            never
  sysmac.sysmac_compartment         0     0     50         -    on          never            never
  sysmac.sysmac_label               0     0     50.8       -    on          never            never
  sysmac.sysmac_policy_enforcement  0     0     50         -    on          never            never
  sysmac.sysmac_user                0     0     50         -    on          never            never
  sysmac.sysmac_obj                 0     0     50         -    on          never            never
  sysmac.sysmac_column_label        0     0     50         -    on          never            never
  sys_hm.check_type                 0     0     50.4       -    on          never            never
  sys_hm.hm_run_t                   0     0     50         -    on          never            never
  sys_hm.check_param                0     0     50.2       -    on          never            never
  sys.dual                          0     0     50.2       -    on          never            never
  sys_catalog._kingbase_loginfo     0     0     50         -    on          never            never
  public.t1                         0     0     50         -    on          never            never
  public.t_perf_test                0     0     20050      -    on          never            never
  kdb_schedule.kdb_jobagent         0     0     50         -    on          never            never
  kdb_schedule.kdb_jobclass         0     0     50         -    on          never            never
  kdb_schedule.kdb_action           0     0     50         -    on          never            never
  kdb_schedule.kdb_schedule         0     0     50         -    on          never            never
  ... 79 more not shown (--limit 0 shows all)
EXIT_CODE=1

finding 是 vacuum.table_disabled：这张表有 5000 个死元组，超过触发线 2050，但表自己设了 autovacuum_enabled=off，autovacuum 永远不会清它。表里 due 是 yes，autovacuum 是 off。
它是 WARN：死元组以后会造成膨胀，但现在什么都没坏。fix 是对这张表跑 VACUUM（名字需要时按 quote_ident 加引号）；跑完死元组还在，说明有东西压着视界，两条 verify（kbdiag txn、kbdiag slots）就是去找它。
autovacuum 开着、只是过了线的表不报。那是 autovacuum 的正常队列，每个 naptime 轮一次；“等太久”需要一条时间线，而它没有客观的值。只在表里标 due。
这条命令的另一个 finding vacuum.disabled（WARN）在实验环境里没有造出来，下面按源码写：autovacuum 或 track_counts 关了，除了防回卷的 vacuum 以外，没有表会被自动清理。fix 是 ALTER SYSTEM SET <那个开关> = on，再 reload。
track_counts 关着时表的 probe 是 skipped：计数器停了，旧值不能当成现在的。

同一张表在 table 命令里怎么显示，见那一页。

退出码

退出码	含义
0	OK
1	WARN
3	UNKNOWN：有数据没采到或看不到
64	参数错误
69	连不上数据库

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