Well it would be a good idea to check the row validity. If the row is partially corrupted, I can get an error (which is quite good) but I can get bad results without an error as well, which is really bad.

After Tom decoded which row yields the problem, I tried to select the data from the corrupted row:

dwhdb=# select * from dwhdata_salemc.fct where time_id = 14 and company_id = 2 and customer_id = 578 and product_id = 1059 and flagsprod_id = 107 and flagssale_id = 2 and account_id = 362 and accttime_id = 13 and invcustomer_id = 578 and salesperson_id = 2 and vendor_id = 16; time_id | company_id | customer_id | product_id | flagsprod_id | flagssale_id | account_id | accttime_id | invcustomer_id | salesperson_id | vendor_id | inv_cost_amt | inv_base_amt | inv_amt | inv_qty | inv_wght | ret_cost_amt | ret_base_amt | ret_amt | ret_qty | ret_wght | unret_cost_amt | unret_base_amt | unret_amt | unret_qty | unret_wght | bonus_forecast | bonus_final | stamp_code
---------+------------+-------------+------------+--------------+--------------+------------+-------------+----------------+----------------+-----------+--------------+--------------+---------+---------+----------+--------------+--------------+---------+---------+----------+----------------+-----------------------------------+-----------------------------------+-----------------------------------+------------+----------------+-------------+----------------------
14 | 2 | 578 | 1059 | 107 | 2 | 362 | 13 | 578 | 2 | 16 | 0.0000 | 0.0000 | 0.1400 | 3.00 | 0.000 | 0.0000 | 0.0000 | 0.0000 | 0.00 | 0.000 | 8.0000 | 000040008000000000004000800000000
                                                               
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| 000040008000000000004000800000000 | 000040008000000000004000800000000 |
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
0.000 |         0.0000 |      0.0000 | INV_ASAS_20060601
                                                   ^^^^^^^^^^^^^^^^^^^
(1 row)

As you can see, the underlined data is bad, but I get no error report. There should be all zeros in the number fields, and 'INV_ASAS_20060101' instead of 'INV_ASAS_20060601' in the stamp field. This all is caused by a single bit being inverted. I can see it very dangerous.

Regards
 Filip Hrbek


----- Original Message ----- From: "Tom Lane" <[EMAIL PROTECTED]>
To: "Alvaro Herrera" <[EMAIL PROTECTED]>
Cc: "Filip Hrbek" <[EMAIL PROTECTED]>; <pgsql-bugs@postgreSQL.org>
Sent: Wednesday, August 30, 2006 4:10 AM
Subject: Re: [BUGS] Partially corrupted table


Alvaro Herrera <[EMAIL PROTECTED]> writes:
Tom Lane wrote:
The underlined word is a field length word that evidently should contain
8, but contains hex 8008.  This causes the tuple-data decoder to step
way past the end of the tuple and off into never-never land.

Hmm, perhaps we could protect against "impossible" length words?

Perhaps.  I'm hesitant to add additional tests into the inner loop of
heap_deform_tuple and friends though.   It's not like it's going to do
anything to recover your data post-corruption :-(

regards, tom lane


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