I would like to propose that we tweak the following error message:
ERROR: unexpected data beyond EOF in block 1472 of relation base/5/16387
HINT: This has been seen to occur with buggy kernels; consider
updating your system.
to something more generic and less confusing. It is coming from
ffae5cc5a602 (2006), and we are probably not running those "buggy"
kernels anywhere. I've seen this error multiple times, but it is
usually due to some external influence overwriting/replacing the files
in PGDATA and some (potentially new) backends open()ing those "new"
files and finding unexpected file layout. In the real world this means
usually:
a. files being potentially accidentally replaced/overwritten, please
see attached file for reproducer
b. some obscure bugs (e.g. in EPAS - PG fork - we have on-demand
automatic partition creation and we had bug/race conditions where
multiple backends end up writing to the same relfilenode oid file)
so how about:
-HINT: This has been seen to occur with buggy kernels; consider
updating your system.
+HINT: This has been observed with files being overwritten, buggy
kernels and potentially other external file system influence.
?
-J.
postgres@postgres:1234 : 8182 # create table t as select i,
repeat(md5(i::text), 100) as txt from generate_series(1 , 100000) i;
SELECT 100000
postgres@postgres:1234 : 8182 # analyze t;
ANALYZE
postgres@postgres:1234 : 8182 # select relfilenode, oid from pg_class where
relname = 't';
relfilenode | oid
-------------+-------
16387 | 16387
(1 row)
postgres@postgres:1234 : 8182 # select pg_relation_filepath('t'::regclass);
pg_relation_filepath
----------------------
base/5/16387
(1 row)
postgres@postgres:1234 : 8182 # \! find /tmp/pg18 -ls | grep 16387
1584697 8 -rw------- 1 postgres postgres 8192 Mar 25 15:44
/tmp/pg18/base/5/16387_vm
1590939 11780 -rw------- 1 postgres postgres 12058624 Mar 25 15:43
/tmp/pg18/base/5/16387
1590944 24 -rw------- 1 postgres postgres 24576 Mar 25 15:44
/tmp/pg18/base/5/16387_fsm
postgres@postgres:1234 : 8182 # \! cp /tmp/pg18/base/5/16387* /tmp/
postgres@postgres:1234 : 8182 # insert into t select i, repeat(md5(i::text),
100) as txt from generate_series(500000, 600000) i;
INSERT 0 100001
postgres@postgres:1234 : 8182 # \! mkdir /tmp/blah
postgres@postgres:1234 : 8182 # \! mv /tmp/pg18/base/5/16387* /tmp/blah
postgres@postgres:1234 : 8182 # \! cp /tmp/16387* /tmp/pg18/base/5/
postgres@postgres:1234 : 8182 # \! find /tmp/pg18 -ls | grep 16387
1591007 8 -rw------- 1 postgres postgres 8192 Mar 25 15:45
/tmp/pg18/base/5/16387_vm
1590947 11776 -rw------- 1 postgres postgres 12058624 Mar 25 15:45
/tmp/pg18/base/5/16387
1590948 24 -rw------- 1 postgres postgres 24576 Mar 25 15:45
/tmp/pg18/base/5/16387_fsm
postgres@postgres:1234 : 8182 # select count(*) from t;
count
--------
200001
(1 row)
postgres@postgres:1234 : 8182 #
\q
postgres@hive:~$ psql -p 1234 -h /tmp
psql (17.2 (Debian 17.2-1.pgdg110+1), server 18devel)
WARNING: psql major version 17, server major version 18.
Some psql features might not work.
Type "help" for help.
postgres@postgres:1234 : 8248 # select count(*) from t;
count
--------
103040
(1 row)
postgres@postgres:1234 : 8248 # vacuum t;
VACUUM
postgres@postgres:1234 : 8248 # insert into t select i, repeat(md5(i::text),
100) as txt from generate_series(700000, 800000) i;
ERROR: unexpected data beyond EOF in block 1472 of relation base/5/16387
HINT: This has been seen to occur with buggy kernels; consider updating your
system.
