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<chapter id="wal">

<title>Reliability and the Write-Ahead Log</title>

then the checkpoint record; then it performs the REDO operation by

scanning forward from the log position indicated in the checkpoint

record. Because the entire content of data pages is saved in the

log on the first page modification after a checkpoint, all pages

log on the first page modification after a checkpoint (assuming

<xref linkend="guc-full-page-writes"> is not disabled), all pages

changed since the checkpoint will be restored to a consistent

state.

</para>