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I wanted to back up a database prior to upgrading to 7.0.2

pg_dump dbname > dbname.bak
FATAL 1: Memory exhausted in AllocSetAlloc()
PQendcopy: resetting connection
SQL query to dump the contents of Table 'tblname' did not execute correctly.
After we read all the table contents from the backend, PQendcopy() failed.
Explanation from backend: ''.
The query was : 'COPY "tblname" TO stdout;
'.

Please help.

Thanks,

Mihai