Tom Lane wrote:
> I'd view this as a postmaster state that propagates to backends.
> Probably you'd enable it by means of a postmaster option, and the
> only way to get out of it is to shut down and restart the postmaster
> without the option.
I've created a patch to make a postmaster read-only.
(attached patch can be applied to 8.0.1)
Read-only state can be enabled/disabled by the postmaster option,
or the postgresql.conf option.
If you start the postmaster with "-r" options,
the cluster will go to read-only.
% pg_ctl -o "-i -r" -D $PGDATA start
Or if you set "readonly_cluster = true" in the postgresql.conf,
the cluster will also become read-only.
Any comments?
--
NAGAYASU Satoshi <[EMAIL PROTECTED]>
OpenSource Development Center,
NTT DATA Corp. http://www.nttdata.co.jp
diff -ru postgresql-8.0.1.orig/src/backend/executor/execMain.c
postgresql-8.0.1/src/backend/executor/execMain.c
--- postgresql-8.0.1.orig/src/backend/executor/execMain.c 2005-01-15
02:53:33.000000000 +0900
+++ postgresql-8.0.1/src/backend/executor/execMain.c 2005-03-21
13:12:22.000000000 +0900
@@ -43,6 +43,7 @@
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
+#include "postmaster/postmaster.h"
#include "utils/acl.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
@@ -127,7 +128,7 @@
* If the transaction is read-only, we need to check if any writes are
* planned to non-temporary tables.
*/
- if (XactReadOnly && !explainOnly)
+ if ( (XactReadOnly || ReadOnlyCluster) && !explainOnly)
ExecCheckXactReadOnly(queryDesc->parsetree);
/*
diff -ru postgresql-8.0.1.orig/src/backend/postmaster/postmaster.c
postgresql-8.0.1/src/backend/postmaster/postmaster.c
--- postgresql-8.0.1.orig/src/backend/postmaster/postmaster.c 2005-01-13
01:38:17.000000000 +0900
+++ postgresql-8.0.1/src/backend/postmaster/postmaster.c 2005-03-21
13:21:17.000000000 +0900
@@ -236,6 +236,8 @@
extern int optreset;
#endif
+bool ReadOnlyCluster = false;
+
/*
* postmaster.c - function prototypes
*/
@@ -440,7 +442,7 @@
opterr = 1;
- while ((opt = getopt(argc, argv,
"A:a:B:b:c:D:d:Fh:ik:lm:MN:no:p:Ss-:")) != -1)
+ while ((opt = getopt(argc, argv,
"A:a:B:b:c:D:d:Fh:ik:lm:MN:no:p:rSs-:")) != -1)
{
switch (opt)
{
@@ -515,6 +517,9 @@
case 'p':
SetConfigOption("port", optarg, PGC_POSTMASTER,
PGC_S_ARGV);
break;
+ case 'r':
+ SetConfigOption("readonly_cluster", "true",
PGC_POSTMASTER, PGC_S_ARGV);
+ break;
case 'S':
/*
diff -ru postgresql-8.0.1.orig/src/backend/tcop/utility.c
postgresql-8.0.1/src/backend/tcop/utility.c
--- postgresql-8.0.1.orig/src/backend/tcop/utility.c 2005-01-25
02:46:29.000000000 +0900
+++ postgresql-8.0.1/src/backend/tcop/utility.c 2005-03-21 13:13:45.000000000
+0900
@@ -47,6 +47,7 @@
#include "parser/parse_expr.h"
#include "parser/parse_type.h"
#include "postmaster/bgwriter.h"
+#include "postmaster/postmaster.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteRemove.h"
#include "storage/fd.h"
@@ -265,7 +266,7 @@
static void
check_xact_readonly(Node *parsetree)
{
- if (!XactReadOnly)
+ if (!XactReadOnly && !ReadOnlyCluster)
return;
/*
diff -ru postgresql-8.0.1.orig/src/backend/utils/misc/guc.c
postgresql-8.0.1/src/backend/utils/misc/guc.c
--- postgresql-8.0.1.orig/src/backend/utils/misc/guc.c 2005-01-01
14:43:08.000000000 +0900
+++ postgresql-8.0.1/src/backend/utils/misc/guc.c 2005-03-21
13:06:42.000000000 +0900
@@ -851,6 +851,15 @@
#endif
},
+ {
+ {"readonly_cluster", PGC_POSTMASTER, UNGROUPED,
+ gettext_noop("Enables the postmaster read-only."),
+ NULL
+ },
+ &ReadOnlyCluster,
+ false, NULL, NULL
+ },
+
/* End-of-list marker */
{
{NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL
diff -ru postgresql-8.0.1.orig/src/include/postmaster/postmaster.h
postgresql-8.0.1/src/include/postmaster/postmaster.h
--- postgresql-8.0.1.orig/src/include/postmaster/postmaster.h 2005-01-01
07:03:39.000000000 +0900
+++ postgresql-8.0.1/src/include/postmaster/postmaster.h 2005-03-21
13:03:16.000000000 +0900
@@ -34,6 +34,7 @@
extern HANDLE PostmasterHandle;
#endif
+extern bool ReadOnlyCluster;
extern int PostmasterMain(int argc, char *argv[]);
extern void ClosePostmasterPorts(bool am_syslogger);
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
