missing chunk number 497 for toast value 504723663

Dear All ,

I am using postgres 7.3.2 on RHEL 4.0.

I know the version is too old but I have no option upgrading the postgres
version.

I have a table with a column type "text". The column consists large data
ranging from 500 kb to 900 kb.

Total there are 50000 records approximately. There are large number of
updates occurring on this table.

Few days ago on another installation an error was generated during pg_dump
"missing chunk number 0 for toast value xxx" or "missing chunk number 0 for
toast value xxx". This problem was resolved by re-indexing the toast table.

But this time there are total 422 records which are giving error of both
"missing chunk number" and "unexpected chunk number" on the "text column
type" and even re-indexing toast table is not resolving the issue. The only
option I am left is to delete these records.

Is there any other way to resolve this issue as deleting the records will
lead to loss of information and the backup I am having also consists of
corrupted records.

Secondly what are probable reasons behind corruption and what can we do to
prevent this error.

Thanks And Regards,

Utsav Turray

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