可以参考https://www.modb.pro/db/331381
pg_toast_2619这个表是pg_statistic系统表的toast扩展表，如果PG报错如下：
ERROR: unexpected chunk number 1 (expected 0) for toast value 16703 in pg_toast_2619
表示pg_toast_2619表损坏，可能pg_statistic也损坏了。这时候可以对整个DB进行analyze，有可能可以修复。如果在analyse过程中还是报错，那么可以通过删掉现有统计信息数据，重新生成来解决:
mydb=# delete from pg_statistic;
mydb=# reindex table pg_statistic;
mydb=# vacuum analyze;
postgres@megait:/data/pg12data/pg_xact$ pg_ctl
pg_ctl pg_ctlcluster
postgres@megait:/data/pg12data/pg_xact$ dd if=/dev/zero of=/data/pg12data/pg_xact/0003 bs=256k count=1
1+0 records in
1+0 records out
262144 bytes (262 kB, 256 KiB) copied, 0.000357276 s, 734 MB/s
postgres@megait:/data/pg12data/pg_xact$ ps -ef |grep post
root 2773 2474 0 14:53 pts/1 00:00:00 su - postgres
postgres 2774 2773 0 14:53 pts/1 00:00:00 -bash
root 3321 2982 0 14:57 pts/2 00:00:00 su - postgres
postgres 3322 3321 0 14:57 pts/2 00:00:00 -bash
root 6729 2291 0 15:40 pts/0 00:00:00 su - postgres
postgres 6730 6729 0 15:40 pts/0 00:00:00 -bash
postgres 7626 6730 0 15:52 pts/0 00:00:00 ps -ef
postgres 7627 6730 0 15:52 pts/0 00:00:00 grep post
postgres@megait:/data/pg12data/pg_xact$ ./start_pg5432.sh
-bash: ./start_pg5432.sh: No such file or directory
postgres@megait:/data/pg12data/pg_xact$ cd /data/run_scripts/
postgres@megait:/data/run_scripts$ ./start_pg5432.sh
waiting for server to start....2022-07-22 15:52:53.445 CST [7647] LOG: starting PostgreSQL 12.11 (Ubuntu 12.11-0ubuntu0.20.04.1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0, 64-bit
2022-07-22 15:52:53.445 CST [7647] LOG: listening on IPv4 address "0.0.0.0", port 5432
2022-07-22 15:52:53.445 CST [7647] LOG: listening on IPv6 address "::", port 5432
2022-07-22 15:52:53.445 CST [7647] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2022-07-22 15:52:54.044 CST [7648] LOG: database system was shut down at 2022-07-22 15:06:17 CST
2022-07-22 15:52:54.044 CST [7649] FATAL: the database system is starting up
2022-07-22 15:52:54.086 CST [7647] LOG: database system is ready to accept connections
2022-07-22 16:19:56.598 CST [9703] ERROR: missing chunk number 0 for toast value 1294135 in pg_toast_2619
2022-07-22 16:19:56.598 CST [9703] STATEMENT: SELECT n.nspname, c.relname, a.attname, tp.typname FROM pg_attribute a JOIN pg_class c on a.attrelid = c.oid JOIN pg_namespace n on c.relnamespace = n.oid JOIN pg_type tp on tp.oid = a.atttypid WHERE a.attnum > 0 ORDER BY nspname, relname
2022-07-22 16:22:33.076 CST [9196] LOG: could not receive data from client: Connection reset by peer
postgres=# 2022-07-22 16:26:53.890 CST [9515] ERROR: canceling statement due to user request
2022-07-22 16:26:53.890 CST [9515] STATEMENT: reindex table pg_statistic;
2022-07-22 16:28:23.827 CST [10316] ERROR: missing chunk number 0 for toast value 1294135 in pg_toast_2619
2022-07-22 16:28:23.827 CST [10316] STATEMENT: SELECT n.nspname, c.relname, a.attname, tp.typname FROM pg_attribute a JOIN pg_class c on a.attrelid = c.oid JOIN pg_namespace n on c.relnamespace = n.oid JOIN pg_type tp on tp.oid = a.atttypid WHERE a.attnum > 0 ORDER BY nspname, relname
postgres=# select count(*) from pg_stat_activity;
count
-------
43
(1 row)
postgres=# vacuum FULL VERBOSE pg_toast.pg_toast_2619
postgres-# ;
INFO: vacuuming "pg_toast.pg_toast_2619"
INFO: "pg_toast_2619": found 5 removable, 16 nonremovable row versions in 6 pages
DETAIL: 0 dead row versions cannot be removed yet.
CPU: user: 0.06 s, system: 0.02 s, elapsed: 0.08 s.
VACUUM
postgres=# vacuum FULL VERBOSE pg_statistic;
INFO: vacuuming "pg_catalog.pg_statistic"
INFO: "pg_statistic": found 0 removable, 116 nonremovable row versions in 9 pages
DETAIL: 0 dead row versions cannot be removed yet.
CPU: user: 0.10 s, system: 0.00 s, elapsed: 0.10 s.
VACUUM
postgres=# \c pg_tables;
You are now connected to database "pg_tables" as user "postgres".
pg_tables=# \l+
ERROR: missing chunk number 0 for toast value 2211903 in pg_toast_2619
CONTEXT: SQL function "shobj_description" during startup
pg_tables=# \d+
ERROR: missing chunk number 0 for toast value 2211903 in pg_toast_2619