3 files changed, 41 insertions, 19 deletions
diff --git a/doc/src/sgml/ref/checkpoint.sgml b/doc/src/sgml/ref/checkpoint.sgml
index 021035888b4..5336c3f5529 100644
--- a/doc/src/sgml/ref/checkpoint.sgml
+++ b/doc/src/sgml/ref/checkpoint.sgml
@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/checkpoint.sgml,v 1.3 2001/01/27 10:19:52 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/checkpoint.sgml,v 1.4 2001/03/13 01:17:05 tgl Exp $ -->
 
 <refentry id="sql-checkpoint">
  <docinfo>
@@ -26,11 +26,12 @@ CHECKPOINT
 
   <para>
    Write-Ahead Logging (WAL) puts a checkpoint in the transaction log
-   every 300 seconds by default.  (This may be changed by the run-time
-   configuration option <parameter>CHECKPOINT_TIMEOUT</parameter>.)
-   The <command>CHECKPOINT</command> command forces a checkpoint at
-   the point at which the command is issued.  The next automatic
-   checkpoint will still happen after the original cycle expires.
+   every so often. (To adjust the automatic checkpoint interval, see
+   the run-time
+   configuration options <parameter>CHECKPOINT_SEGMENTS</parameter>
+   and <parameter>CHECKPOINT_TIMEOUT</parameter>.)
+   The <command>CHECKPOINT</command> command forces an immediate checkpoint
+   when the command is issued, without waiting for a scheduled checkpoint.
   </para>
 
   <para>
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index b23dcbf5a60..f321cea669b 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.55 2001/02/18 05:30:12 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.56 2001/03/13 01:17:05 tgl Exp $
 -->
 
 <Chapter Id="runtime">
@@ -976,6 +976,11 @@ env PGOPTIONS='-c geqo=off' psql
 	fsyncs because of performance problems, you may wish to reconsider
 	your choice.
        </para>
+
+       <para>
+	This option can only be set at server start or in the
+	<filename>postgresql.conf</filename> file.
+       </para>
       </listitem>
      </varlistentry>
 
@@ -1193,10 +1198,24 @@ env PGOPTIONS='-c geqo=off' psql
 
     <variablelist>
      <varlistentry>
+      <term>CHECKPOINT_SEGMENTS (<type>integer</type>)</term>
+      <listitem>
+       <para>
+        Maximum distance between automatic WAL checkpoints, in logfile
+	segments (each segment is normally 16 megabytes).
+	This option can only be set at server start or in the
+	<filename>postgresql.conf</filename> file.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term>CHECKPOINT_TIMEOUT (<type>integer</type>)</term>
       <listitem>
        <para>
-        Frequency of automatic WAL checkpoints, in seconds.
+        Maximum time between automatic WAL checkpoints, in seconds.
+	This option can only be set at server start or in the
+	<filename>postgresql.conf</filename> file.
        </para>
       </listitem>
      </varlistentry>
@@ -1205,8 +1224,8 @@ env PGOPTIONS='-c geqo=off' psql
       <term>WAL_BUFFERS (<type>integer</type>)</term>
       <listitem>
        <para>
-        Number of buffers for WAL.  This option can only be set at
-        server start.
+        Number of disk-page buffers for WAL log.  This option can only be set
+	at server start.
        </para>
       </listitem>
      </varlistentry>
@@ -1226,7 +1245,8 @@ env PGOPTIONS='-c geqo=off' psql
       <listitem>
        <para>
         Number of log files that are created in advance at checkpoint
-        time.  This option can only be set at server start.
+        time.  This option can only be set at server start or in the
+	<filename>postgresql.conf</filename> file.
        </para>
       </listitem>
      </varlistentry>
@@ -1909,7 +1929,7 @@ default:\
      <listitem>
       <para>
        This is the <firstterm>Immediate Shutdown</firstterm> which
-       will cause the postmaster to send a SIGUSR1 to all backends and
+       will cause the postmaster to send a SIGQUIT to all backends and
        exit immediately (without properly shutting down the database
        system). When WAL is implemented, this will lead to recovery on
        start-up. Right now it's not recommendable to use this option.
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml
index e706ee271c6..c92ccd9d230 100644
--- a/doc/src/sgml/wal.sgml
+++ b/doc/src/sgml/wal.sgml
@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.3 2001/02/26 00:50:07 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.4 2001/03/13 01:17:05 tgl Exp $ -->
 
 <chapter id="wal">
  <title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>
@@ -257,7 +257,7 @@
    The <acronym>WAL</acronym> log is held on the disk as a set of 16
    MB files called <firstterm>segments</firstterm>.  By default a new
    segment is created only if more than 75% of the current segment is
-   used. One can instruct the server to create up to 64 log segments
+   used. One can instruct the server to pre-create up to 64 log segments
    at checkpoint time by modifying the <varname>WAL_FILES</varname>
    configuration parameter.
   </para>
@@ -272,11 +272,12 @@
   </para>
 
   <para>
-   By default, the postmaster spawns a special backend process to
-   create the next checkpoint 300 seconds after the previous
-   checkpoint's creation.  One can change this interval by modifying
-   the <varname>CHECKPOINT_TIMEOUT</varname> parameter.  It is also
-   possible to force a checkpoint by using the SQL command
+   The postmaster spawns a special backend process every so often
+   to create the next checkpoint.  A checkpoint is created every
+   <varname>CHECKPOINT_SEGMENTS</varname> log segments, or every
+   <varname>CHECKPOINT_TIMEOUT</varname> seconds, whichever comes first.
+   The default settings are 3 segments and 300 seconds respectively.
+   It is also possible to force a checkpoint by using the SQL command
    <command>CHECKPOINT</command>.
   </para>