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Fix typo, other minor improvements.

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Neil Conway 2004-11-15 04:35:57 +00:00
parent f6474586ea
commit db1531f6d8
1 changed files with 12 additions and 12 deletions
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doc/src/sgml/wal.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.29 2004/08/08 04:34:43 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.30 2004/11/15 04:35:57 neilc Exp $ -->
<chapter id="wal">
<title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>
@ -104,17 +104,17 @@
</para>
<para>
<firstterm>Checkpoints</firstterm><indexterm><primary>checkpoint</></> are points in the sequence of
transactions at which it is guaranteed that the data files have
been updated with all information logged before the checkpoint. At
checkpoint time, all dirty data pages are flushed to disk and a
special checkpoint record is written to the log file. As result, in
the event of a crash, the recoverer knows from what point in the
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 no longer needed and can be recycled or
removed. (When <acronym>WAL</acronym> archiving is being done, the
<firstterm>Checkpoints</firstterm><indexterm><primary>checkpoint</></>
are points in the sequence of transactions at which it is guaranteed
that the data files have been updated with all information logged before
the checkpoint. At checkpoint time, all dirty data pages are flushed to
disk and a special checkpoint record is written to the log file. As a
result, in the event of a crash, the crash recovery procedure knows from
what point in the log (known as the redo record) it should start the
REDO operation, since any changes made to data files before that point
are already on disk. After a checkpoint has been made, any log segments
written before the redo record are no longer needed and can be recycled
or removed. (When <acronym>WAL</acronym> archiving is being done, the
log segments must be archived before being recycled or removed.)
</para>