<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.86 2001/09/30 18:57:45 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.87 2001/09/30 20:16:21 tgl Exp $
-->
<Chapter Id="runtime">
<term><varname>LOG_CONNECTIONS</varname> (<type>boolean</type>)</term>
<listitem>
<para>
- Prints a line informing about each successful connection to
+ Prints a line informing about each successful connection in
the server log. This is off by default, although it is
probably very useful. This option can only be set at server
- start.
+ start or in the <filename>postgresql.conf</filename>
+ configuration file.
</para>
</listitem>
</varlistentry>
<listitem>
<para>
Sets the maximum number of simultaneously open files in each server
- process. The default is 1000. The limit actually used by the code
+ subprocess. The default is 1000. The limit actually used by the code
is the smaller of this setting and the result of
<literal>sysconf(_SC_OPEN_MAX)</literal>.
Therefore, on systems where sysconf returns a reasonable limit,
processes all try to open that many files. If you find yourself
seeing <quote>Too many open files</> failures, try reducing this
setting.
- This option can only be set at server start.
+ This option can only be set at server start or in the
+ <filename>postgresql.conf</filename> configuration file;
+ if changed in the configuration file, it only affects
+ subsequently-started server subprocesses.
</para>
</listitem>
</varlistentry>
* Support for grand unified configuration scheme, including SET
* command, configuration file, and command line options.
*
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.54 2001/09/30 18:57:45 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.55 2001/09/30 20:16:21 tgl Exp $
*
* Copyright 2000 by PostgreSQL Global Development Group
* Written by Peter Eisentraut <peter_e@gmx.net>.
* precise rules. Note that we don't want to throw errors if we're in
* the SIGHUP context. In that case we just ignore the attempt.
*/
- if (record->context == PGC_POSTMASTER && context != PGC_POSTMASTER)
+ switch (record->context)
{
- if (context != PGC_SIGHUP)
- elog(ERROR, "'%s' cannot be changed after server start", name);
- else
- return true;
- }
- else if (record->context == PGC_SIGHUP && context != PGC_SIGHUP &&
- context != PGC_POSTMASTER)
- {
- elog(ERROR, "'%s' cannot be changed now", name);
-
- /*
- * Hmm, the idea of the SIGHUP context is "ought to be global, but
- * can be changed after postmaster start". But there's nothing
- * that prevents a crafty administrator from sending SIGHUP
- * signals to individual backends only.
- */
- }
- else if (record->context == PGC_BACKEND && context != PGC_BACKEND
- && context != PGC_POSTMASTER)
- {
- if (context != PGC_SIGHUP)
- elog(ERROR, "'%s' cannot be set after connection start", name);
- else
- return true;
+ case PGC_POSTMASTER:
+ if (context == PGC_SIGHUP)
+ return true;
+ if (context != PGC_POSTMASTER)
+ elog(ERROR, "'%s' cannot be changed after server start", name);
+ break;
+ case PGC_SIGHUP:
+ if (context != PGC_SIGHUP && context != PGC_POSTMASTER)
+ elog(ERROR, "'%s' cannot be changed now", name);
+ /*
+ * Hmm, the idea of the SIGHUP context is "ought to be global, but
+ * can be changed after postmaster start". But there's nothing
+ * that prevents a crafty administrator from sending SIGHUP
+ * signals to individual backends only.
+ */
+ break;
+ case PGC_BACKEND:
+ if (context == PGC_SIGHUP)
+ {
+ /*
+ * If a PGC_BACKEND parameter is changed in the config file,
+ * we want to accept the new value in the postmaster (whence
+ * it will propagate to subsequently-started backends), but
+ * ignore it in existing backends. This is a tad klugy, but
+ * necessary because we don't re-read the config file during
+ * backend start.
+ */
+ if (IsUnderPostmaster)
+ return true;
+ }
+ else if (context != PGC_BACKEND && context != PGC_POSTMASTER)
+ elog(ERROR, "'%s' cannot be set after connection start", name);
+ break;
+ case PGC_SUSET:
+ if (context == PGC_USERSET || context == PGC_BACKEND)
+ elog(ERROR, "permission denied");
+ break;
+ case PGC_USERSET:
+ /* always okay */
+ break;
}
- else if (record->context == PGC_SUSET &&
- (context == PGC_USERSET || context == PGC_BACKEND))
- elog(ERROR, "permission denied");
-
/*
* Evaluate value and set variable
* External declarations pertaining to backend/utils/misc/guc.c and
* backend/utils/misc/guc-file.l
*
- * $Id: guc.h,v 1.9 2001/06/18 16:14:43 momjian Exp $
+ * $Id: guc.h,v 1.10 2001/09/30 20:16:21 tgl Exp $
*/
#ifndef GUC_H
#define GUC_H
* certain point in their main loop. It's safer to wait than to read a
* file asynchronously.)
*
- * BACKEND options can only be set at postmaster startup or with the
- * PGOPTIONS variable from the client when the connection is
- * initiated. Note that you cannot change this kind of option using
- * the SIGHUP mechanism, that would defeat the purpose of this being
- * fixed for a given backend once started.
+ * BACKEND options can only be set at postmaster startup, from the
+ * configuration file, or with the PGOPTIONS variable from the client
+ * when the connection is initiated. Furthermore, an already-started
+ * backend will ignore changes to such an option in the configuration
+ * file. The idea is that these options are fixed for a given backend
+ * once it's started, but they can vary across backends.
*
* SUSET options can be set at postmaster startup, with the SIGHUP
* mechanism, or from SQL if you're a superuser. These options cannot
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