On 2023-09-15 23:38, Nathan Bossart wrote:
On Fri, Sep 15, 2023 at 02:48:55PM +0200, Daniel Gustafsson wrote:
On 15 Sep 2023, at 12:49, Alvaro Herrera <alvhe...@alvh.no-ip.org>
wrote:
On 2023-Sep-15, Daniel Gustafsson wrote:
-basic_archive_configured(ArchiveModuleState *state)
+basic_archive_configured(ArchiveModuleState *state, const char
**errmsg)
The variable name errmsg implies that it will contain the errmsg()
data when it
in fact is used for errhint() data, so it should be named
accordingly.
I have no objection to allowing this callback to provide additional
information, but IMHO this should use errdetail() instead of errhint().
In
the provided patch, the new message explains how the module is not
configured. It doesn't hint at how to fix it (although presumably one
could figure that out pretty easily).
It's probably better to define the interface as
ArchiveCheckConfiguredCB
functions returning an allocated string in the passed pointer which
the caller
is responsible for freeing.
That does seem more flexible.
Also note that this callback is documented in archive-modules.sgml,
so
that needs to be updated as well. This also means you can't
backpatch
this change, or you risk breaking external software that implements
this
interface.
Absolutely, this is master only for v17.
+1
Thank you for all of your comments!
They are all really constructive and I totally agree with the points you
brought up.
I have updated the patch accordingly.
Please let me know if you have any further suggestions that I can
improve more.
Best regards,
Tung Nguyen
diff --git a/contrib/basic_archive/basic_archive.c b/contrib/basic_archive/basic_archive.c
index 4d78c31859..7b8673f338 100644
--- a/contrib/basic_archive/basic_archive.c
+++ b/contrib/basic_archive/basic_archive.c
@@ -48,7 +48,7 @@ typedef struct BasicArchiveData
static char *archive_directory = NULL;
static void basic_archive_startup(ArchiveModuleState *state);
-static bool basic_archive_configured(ArchiveModuleState *state);
+static bool basic_archive_configured(ArchiveModuleState *state, char **logdetail);
static bool basic_archive_file(ArchiveModuleState *state, const char *file, const char *path);
static void basic_archive_file_internal(const char *file, const char *path);
static bool check_archive_directory(char **newval, void **extra, GucSource source);
@@ -159,9 +159,15 @@ check_archive_directory(char **newval, void **extra, GucSource source)
* Checks that archive_directory is not blank.
*/
static bool
-basic_archive_configured(ArchiveModuleState *state)
+basic_archive_configured(ArchiveModuleState *state, char **logdetail)
{
- return archive_directory != NULL && archive_directory[0] != '\0';
+ if (archive_directory == NULL || archive_directory[0] == '\0')
+ {
+ *logdetail = pstrdup("WAL archiving failed because basic_archive.archive_directory is not set");
+ return false;
+ }
+ else
+ return true;
}
/*
diff --git a/doc/src/sgml/archive-modules.sgml b/doc/src/sgml/archive-modules.sgml
index 7064307d9e..f9f6177844 100644
--- a/doc/src/sgml/archive-modules.sgml
+++ b/doc/src/sgml/archive-modules.sgml
@@ -101,7 +101,7 @@ typedef void (*ArchiveStartupCB) (ArchiveModuleState *state);
assumes the module is configured.
<programlisting>
-typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state);
+typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state, char **logdetail);
</programlisting>
If <literal>true</literal> is returned, the server will proceed with
@@ -112,7 +112,9 @@ typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state);
WARNING: archive_mode enabled, yet archiving is not configured
</screen>
In the latter case, the server will periodically call this function, and
- archiving will proceed only when it returns <literal>true</literal>.
+ archiving will proceed only when it returns <literal>true</literal>. The
+ archiver may also emit the detail explaining how the module is not configured
+ to the sever log if the archive module has any.
</para>
</sect2>
diff --git a/src/backend/archive/shell_archive.c b/src/backend/archive/shell_archive.c
index 157ca4c751..c957a18ee7 100644
--- a/src/backend/archive/shell_archive.c
+++ b/src/backend/archive/shell_archive.c
@@ -23,7 +23,7 @@
#include "common/percentrepl.h"
#include "pgstat.h"
-static bool shell_archive_configured(ArchiveModuleState *state);
+static bool shell_archive_configured(ArchiveModuleState *state, char **logdetail);
static bool shell_archive_file(ArchiveModuleState *state,
const char *file,
const char *path);
@@ -43,7 +43,7 @@ shell_archive_init(void)
}
static bool
-shell_archive_configured(ArchiveModuleState *state)
+shell_archive_configured(ArchiveModuleState *state, char **logdetail)
{
return XLogArchiveCommand[0] != '\0';
}
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 46af349564..2fd1d03b09 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,8 @@ pgarch_ArchiverCopyLoop(void)
{
struct stat stat_buf;
char pathname[MAXPGPATH];
-
+ char *logdetail;
+
/*
* Do not initiate any more archive commands after receiving
* SIGTERM, nor after the postmaster has died unexpectedly. The
@@ -410,10 +411,13 @@ pgarch_ArchiverCopyLoop(void)
/* can't do anything if not configured ... */
if (ArchiveCallbacks->check_configured_cb != NULL &&
- !ArchiveCallbacks->check_configured_cb(archive_module_state))
+ !ArchiveCallbacks->check_configured_cb(archive_module_state, &logdetail))
{
ereport(WARNING,
- (errmsg("archive_mode enabled, yet archiving is not configured")));
+ (errmsg("archive_mode enabled, yet archiving is not configured")),
+ (logdetail != NULL) ? errdetail("%s", logdetail) : 0);
+ if (logdetail != NULL)
+ pfree(logdetail);
return;
}
diff --git a/src/include/archive/archive_module.h b/src/include/archive/archive_module.h
index 679ce5a6db..43bd0ff4c2 100644
--- a/src/include/archive/archive_module.h
+++ b/src/include/archive/archive_module.h
@@ -36,7 +36,7 @@ typedef struct ArchiveModuleState
* archive modules documentation.
*/
typedef void (*ArchiveStartupCB) (ArchiveModuleState *state);
-typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state);
+typedef bool (*ArchiveCheckConfiguredCB) (ArchiveModuleState *state, char **logdetail);
typedef bool (*ArchiveFileCB) (ArchiveModuleState *state, const char *file, const char *path);
typedef void (*ArchiveShutdownCB) (ArchiveModuleState *state);
