Re: 8.4.0 data loss / HOT-related bug

On Fri, Aug 21, 2009 at 4:04 PM, Radoslaw Zielinski<radek@pld-linux.org> wr=
ote:

> This particular row currently has last_modified=3D"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. =A0Andrew 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=3D# 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)


--=20
greg
http://mit.edu/~gsstark/resume.pdf