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Re: 8.4.0 data loss / HOT-related bug

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Radoslaw Zielinski <radek(at)pld-linux(dot)org>
Cc: pgsql-bugs(at)postgresql(dot)org
Subject: Re: 8.4.0 data loss / HOT-related bug
Date: 2009-08-21 16:03:00
Message-ID: 407d949e0908210903x3316f504g4d1cd8219b66ad69@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-bugs
On Fri, Aug 21, 2009 at 4:04 PM, Radoslaw Zielinski<radek(at)pld-linux(dot)org> wrote:

> This particular row currently has last_modified="2009-08-11", but table_log
> says it has been updated on "2009-08-12" -- so, data loss.

These are all very low transaction ids. you say it was a week of
production before this happened?

How did you migrate your data? Was it a normal pg_dump restore? Or did
you do anything funny with slony or pg_migrate?

> Please see the attachment for the xmin,xmax,cmin,cmax,ctid values of
> these rows.  Andrew Gireth has asked for the hexdump of page 539 of the
> "promocje" table: http://radek.cc/promocje.hexdump

Here's a dump of that page btw.

postgres=# select (h).* from (select  heap_page_items(p) as h from p) as x;
 lp | lp_off | lp_flags | lp_len | t_xmin | t_xmax | t_field3 |
t_ctid  | t_infomask2 | t_infomask | t_hoff |                  t_bits
                | t_oid
----+--------+----------+--------+--------+--------+----------+----------+-------------+------------+--------+------------------------------------------+-------
  1 |   6896 |        1 |   1296 |   3747 |      0 |        0 |
(539,1)  |          15 |      10499 |     28 |
1011111000001110000000000000000000000000 |
  2 |      5 |        2 |      0 |        |        |          |
  |             |            |        |
          |
  3 |   1164 |        1 |    504 |   3842 |   3843 |        0 |
(539,3)  |          15 |       2439 |     28 |
1011111000001110000000000000000000000000 |
  4 |   6396 |        1 |    500 |   3806 |      0 |        0 |
(539,4)  |          15 |      10503 |     28 |
1011111000001110000000000000000000000000 |
  5 |   5928 |        1 |    468 |   3810 |      0 |        0 |
(539,5)  |      -32753 |      10503 |     28 |
1011111000001110000000000000000000000000 |
  6 |   5176 |        1 |    752 |   3812 |   3813 |        0 |
(539,6)  |          15 |       2439 |     28 |
1011111000001110000000000000000000000000 |
  7 |   4600 |        1 |    576 |   3819 |   6179 |        0 |
(539,12) |       16399 |      10503 |     28 |
1011101000001110000000000000000000000000 |
  8 |   4076 |        1 |    524 |   3823 |   3825 |        0 |
(539,8)  |          15 |       2439 |     28 |
1011111000001110000000000000000000000000 |
  9 |   2872 |        1 |   1204 |   3830 |      0 |        0 |
(539,9)  |          15 |      10499 |     28 |
1011111000001110000000000000000000000000 |
 10 |   1668 |        1 |   1204 |   3831 |   3832 |        0 |
(539,10) |          15 |       2435 |     28 |
1011111000001110000000000000000000000000 |
 11 |      0 |        3 |      0 |        |        |          |
  |             |            |        |
          |
 12 |      0 |        0 |      0 |        |        |          |
  |             |            |        |
          |
(12 rows)


-- 
greg
http://mit.edu/~gsstark/resume.pdf

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Next:From: Greg StarkDate: 2009-08-21 16:12:50
Subject: Re: 8.4.0 data loss / HOT-related bug
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Subject: 8.4.0 data loss / HOT-related bug

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