Question

Using the COPY command (http://www.postgresql.org/docs/9.1/static/sql-copy.html) I get each CHAR column filled up with spaces in the resulting text file.
Is there any way to trim them during this procedure ?

Answer 1

You can specify a query instead of a table name with COPY so you can add a TRIM call to strip off the leading and trailing whitespace from your char(n) columns:

copy (select trim(some_column), ... from some_table) to stdout with csv;