redo record -> undo record, Tom Lane.

doc/src/sgml/wal.sgml

-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.5 2001/03/16 05:44:33 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.6 2001/05/15 13:57:37 momjian Exp $ -->
 
 <chapter id="wal">
  <title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>
@@ -243,7 +243,7 @@
    log (known as the redo record) it should start the REDO operation,
    since any changes made to data files before that record are already
    on disk. After a checkpoint has been made, any log segments written
-   before the redo record are removed, so checkpoints are used to free
+   before the undo records are removed, so checkpoints are used to free
    disk space in the <acronym>WAL</acronym> directory. (When
    <acronym>WAL</acronym>-based <acronym>BAR</acronym> is implemented,
    the log segments can be archived instead of just being removed.)