Обсуждение: BUG #18090: Encountering Toast Table Corruption and Missing Chunk Number Error During PostgreSQL Data Migration

The following bug has been logged on the website:

Bug reference:      18090
Logged by:          Root Cause
Email address:      rootcause000@gmail.com
PostgreSQL version: Unsupported/Unknown
Operating system:   Microsoft Windows Server 2019 Standard
Description:

Version - PostgreSQL 10.21, compiled by Visual C++ build 1800, 64-bit

Platform - Windows

When migrating data from PostgreSQL 10.21 to 14.7, we encountered an issue
during the dump process related to table corruption, resulting in the error
message 'could not open file "base/16510/37857": No such file or
directory.'

ERROR: could not open file "base/16510/37857": No such file or directory

Upon checking the 'relkind' for 'relfilenode', it was determined that the
type is toast table. In an attempt to recover the data, we initially tried
truncating the toast table, but encountered an error preventing successful
truncation. As a workaround, we created a new empty file named "37857" under
the directory "base/16510." However, this led to a new error: 'missing chunk
number 0 for toast value 15977662 in pg_toast_37722.'

ERROR: missing chunk number 0 for toast value 15977662 in pg_toast_37722

ProdDB=# select count(*) from prrhtab;
 count
--------
 232966
(1 row)

ProdDB=# select * from prrhtab;
ERROR:  could not open file "base/16510/37857": No such file or directory
ProdDB=# select relname, relkind from pg_class where relfilenode=37857;
    relname     | relkind
----------------+---------
 pg_toast_37722 | t
(1 row)

ProdDB=# select * from pg_toast.pg_toast_37722;
ERROR:  could not open file "base/16510/37857": No such file or directory
ProdDB=# select count(*) from pg_toast.pg_toast_37722;
ERROR:  could not open file "base/16510/37857": No such file or directory

ProdDB=# truncate table pg_toast.pg_toast_37722;
ERROR:  "pg_toast_37722" is not a table

ProdDB=# select count(*) from pg_toast.pg_toast_37722;
 count
-------
     0
(1 row)

ProdDB=# select * from prrhtab;
ERROR:  could not read block 2635 in file "base/16510/37857": read only 0 of
8192 bytes
ProdDB=# reindex table prrhtab;
REINDEX
ProdDB=# select * from prrhtab;
ERROR:  missing chunk number 0 for toast value 15977662 in pg_toast_37722

ProdDB=# select count(*) from prrhtab;
 count
--------
 232966
(1 row)


ProdDB=# select * from prrhtab order by id desc limit 1;
    id   
---------
 1177027 
(1 row)
To resolve this issue, we proceeded to remove the corrupted rows one by one,
and as a result, the 'missing chunk number' error no longer occurred.

Unfortunately, we do not have a backup from before the table corruption
occurred. While we were able to proceed with the migration using the
aforementioned approach, we were uncertain if there might be an alternative
method to resolve this issue without any data loss. Furthermore, the process
of checking rows one by one to resolve the 'missing chunk number' error does
not appear to be efficient. Therefore, we would appreciate any suggestions
for an optimal solution and what could have been the cause so that similar
issues can be avoided in future.

On Tue, 2023-09-05 at 20:23 +0000, PG Bug reporting form wrote:
> The following bug has been logged on the website:
>
> Bug reference:      18090
> Logged by:          Root Cause
> Email address:      rootcause000@gmail.com
> PostgreSQL version: Unsupported/Unknown
> Operating system:   Microsoft Windows Server 2019 Standard
> Description:       
>
> Version - PostgreSQL 10.21, compiled by Visual C++ build 1800, 64-bit
>
> Platform - Windows
>
> When migrating data from PostgreSQL 10.21 to 14.7, we encountered an issue
> during the dump process related to table corruption, resulting in the error
> message 'could not open file "base/16510/37857": No such file or
> directory.'
>
> ERROR: could not open file "base/16510/37857": No such file or directory

Where is the PostgreSQL bug you want to report?
If you want to claim that PostgreSQL removed the file behind that table,
you need some evidence.

Yours,
Laurenz Albe