does postgreSQL have any mechanism like Oracle's Redo-log or the 'logupdate' option of MySQL which log only those
queriesthat cause really happened changes to databases? In postgreSQL, how to do things like MySQL's "flush logs" and
Oracle's"alter database archivelog"? what's the information in $PGDATA/pg_log? how to browse it? how to delete rows
having'invalid' timestamp value? i use "delete from tablename where timestampColName = 'invalid';",but can't delete
them.(MypostgreSQL is version 6.5)