pg_dump fails, data integrity imperfect

At some point between april 13 and now a single row in my 'orders' table
became compromised and caused the failure of pg_dump upon which I had
been depending for a backup, sort of. I say sort of because I allowed
each days dump to overwrite the previous and as such cannot point to a
specific day and say "that's when it came unstuck". Upon deletion of the
afflicted row the pg_dump proceeded in an orderly manner.
Is there any obvious/common cause of corruption of (probably varchar)
data?
Is there any simple/automated detection scheme?

The database is on RedHat 6.1 linux box with a paltry 64 megs of ram to
entertain its celeron 333. The dbase version is postgres 6.5.3 .
The whole kit is about to be upgraded to RedHat7.1/Postgres7.03 128Meg
533Mhz.

[postgres(at)midas pgsql]$ pg_dump bella>data/sunday.dump
FATAL 1: Memory exhausted in AllocSetAlloc()
PQendcopy: resetting connection
SQL query to dump the contents of Table 'orders' did not execute
correctly. After we read all the table contents from the backend,
PQendcopy() failed. Explanation from backend: 'FATAL 1: Memory
exhausted in AllocSetAlloc()
'.
The query was: 'COPY "orders" TO stdout;
'.
[postgres(at)midas pgsql]$

This is the last few lines that the dump output. I have seperated
individual orders with a blank line for clarity

16997 1 Fri Dec 15 16:37:12 2000 PST t Cash $2.94 $0.19 $0.00 1 Regular
SLC VEG $2.75<!> <!> <!>ISPEC<!><*> COMPLETE Pickup f 716736777

16998 9802215 Fri Dec 15 16:43:21 2000 PST f Cash $20.38 $1.33 $0.00 1
Medium HAW $12.25<!> <!> <!>0 0 1 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 0 1ISPEC<!><*>2 Small T.S. $3.00<!> <!> <!>ISPEC<!><*>4
Regular G.B. $3.80<!> <!> <!>ISPEC<!><*> COMPLETE Delivery f 716736777

16999 9908055 Fri Dec 15 16:45:12 2000 PST f Cash $17.92 $1.17 $0.00 1
Regular WH CHICK $9.75<!> <!> <!>0 0 0 1ISPEC<!><*>1 Regular L.M.S.
$7.00<!> <!> <!>ISPEC<!><*> COMPLETE Delivery f 716736777

17000 9855620 Fri Dec 15 16:48:15 2000 PST f Cash $20.60 $1.35 $0.00 1
Small BASIC $6.25<!> <!> <!>0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1 0 0 0ISPEC<!><*>1 Small GOURMET $10.50<!> <!> <!>0 1
0 0 0 1 0 1 0 1 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 0 0 0 0 0 0 1ISPEC<!><*>2
Regular Pop $2.50<!>2x R.B.<!> <!>0 0 0 0 0 0 2ISPEC<!><*> COMPLETE
Delivery f 716736777

17225 1 Sun Dec 17 01:45:29 2000 PST t Cash $2.94 $0.19 $0.00 447 19688
19I! 8 19I!  f

Here's the 'wounded' ordernumber as queried from a previously dumped
version

bella=# select * from orders where ordnumber=17225;
ordnumber | customernumber | ordertime | pickupdel |
paymethod | total | gstotal | discount |
items | status | pudelcharge | edits | wastecolumn
| staff
-----------+----------------+------------------------+-----------+-----------+-------+---------+----------+-----------------------------------------------+----------+-------------+-------+-------------+-----------
17225 | 1 | 2000-12-17 01:45:29-08 | t |
Cash | $2.94 | $0.19 | $0.00 | 1 Regular SLC VEG $2.75<!> <!>
<!>ISPEC<!><*> | COMPLETE | Pickup | f | |
716736777
(1 row)

--

Glenn Wittrock

Linux: when you need to run like a greased weasel.