pg_resetwal: Add --char-signedness option to change the default char signedness.

With the newly added option --char-signedness, pg_resetwal updates the
default char signedness flag in the controlfile. This option is
primarily intended for an upcoming patch that pg_upgrade supports
preserving the default char signedness during upgrades, and is not
meant for manual operation.

Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/CB11ADBC-0C3F-4FE0-A678-666EE80CBB07%40amazon.com

diff --git a/doc/src/sgml/ref/pg_resetwal.sgml b/doc/src/sgml/ref/pg_resetwal.sgml
index cf9c7e70f27127b9566896278b1255a8394e8a62..dd011d246c16636fad9a9e7d7945bfe6cf01b22d 100644 (file)
--- a/doc/src/sgml/ref/pg_resetwal.sgml
+++ b/doc/src/sgml/ref/pg_resetwal.sgml
@@ -171,6 +171,25 @@ PostgreSQL documentation
   </para>
 
   <variablelist>
+   <varlistentry>
+    <term><option>--char-signedness=<replaceable class="parameter">option</replaceable></option></term>
+    <listitem>
+     <para>
+      Manually set the default char signedness. Possible values are
+      <literal>signed</literal> and <literal>unsigned</literal>.
+     </para>
+     <para>
+      For a database cluster that <command>pg_upgrade</command> upgraded from
+      a <productname>PostgreSQL</productname> version before 18, the safe
+      value would be the default <type>char</type> signedness of the platform
+      that ran the cluster before that upgrade. For all other
+      clusters, <literal>signed</literal> would be the safe value. However,
+      this option is exclusively for use with <command>pg_upgrade</command>
+      and should not normally be used manually.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><option>-c <replaceable class="parameter">xid</replaceable>,<replaceable class="parameter">xid</replaceable></option></term>
     <term><option>--commit-timestamp-ids=<replaceable class="parameter">xid</replaceable>,<replaceable class="parameter">xid</replaceable></option></term>

diff --git a/src/bin/pg_resetwal/pg_resetwal.c b/src/bin/pg_resetwal/pg_resetwal.c
index ed73607a46f0687b0f12f36a54da144590bebefa..31bc0abff16a87e9e3cb16ada6ca44f0a4f124d4 100644 (file)
--- a/src/bin/pg_resetwal/pg_resetwal.c
+++ b/src/bin/pg_resetwal/pg_resetwal.c
@@ -75,6 +75,7 @@ static TimeLineID minXlogTli = 0;
 static XLogSegNo minXlogSegNo = 0;
 static int     WalSegSz;
 static int     set_wal_segsize;
+static int     set_char_signedness = -1;
 
 static void CheckDataVersion(void);
 static bool read_controlfile(void);
@@ -106,6 +107,7 @@ main(int argc, char *argv[])
                {"oldest-transaction-id", required_argument, NULL, 'u'},
                {"next-transaction-id", required_argument, NULL, 'x'},
                {"wal-segsize", required_argument, NULL, 1},
+               {"char-signedness", required_argument, NULL, 2},
                {NULL, 0, NULL, 0}
        };
 
@@ -302,6 +304,23 @@ main(int argc, char *argv[])
                                        break;
                                }
 
+                       case 2:
+                               {
+                                       errno = 0;
+
+                                       if (pg_strcasecmp(optarg, "signed") == 0)
+                                               set_char_signedness = 1;
+                                       else if (pg_strcasecmp(optarg, "unsigned") == 0)
+                                               set_char_signedness = 0;
+                                       else
+                                       {
+                                               pg_log_error("invalid argument for option %s", "--char-signedness");
+                                               pg_log_error_hint("Try \"%s --help\" for more information.", progname);
+                                               exit(1);
+                                       }
+                                       break;
+                               }
+
                        default:
                                /* getopt_long already emitted a complaint */
                                pg_log_error_hint("Try \"%s --help\" for more information.", progname);
@@ -456,6 +475,9 @@ main(int argc, char *argv[])
        if (set_wal_segsize != 0)
                ControlFile.xlog_seg_size = WalSegSz;
 
+       if (set_char_signedness != -1)
+               ControlFile.default_char_signedness = (set_char_signedness == 1);
+
        if (minXlogSegNo > newXlogSegNo)
                newXlogSegNo = minXlogSegNo;
 
@@ -779,6 +801,8 @@ PrintControlValues(bool guessed)
                   (ControlFile.float8ByVal ? _("by value") : _("by reference")));
        printf(_("Data page checksum version:           %u\n"),
                   ControlFile.data_checksum_version);
+       printf(_("Default char data signedness:         %s\n"),
+                  (ControlFile.default_char_signedness ? _("signed") : _("unsigned")));
 }
 
 
@@ -1188,6 +1212,7 @@ usage(void)
        printf(_("  -O, --multixact-offset=OFFSET    set next multitransaction offset\n"));
        printf(_("  -u, --oldest-transaction-id=XID  set oldest transaction ID\n"));
        printf(_("  -x, --next-transaction-id=XID    set next transaction ID\n"));
+       printf(_("      --char-signedness=OPTION     set char signedness to \"signed\"  or \"unsigned\"\n"));
        printf(_("      --wal-segsize=SIZE           size of WAL segments, in megabytes\n"));
 
        printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);

diff --git a/src/bin/pg_resetwal/t/001_basic.pl b/src/bin/pg_resetwal/t/001_basic.pl
index 323cd483cf31d2850ba23cb629dc78a2b8fe279a..d6bbbd0ceda38c7d926b603135be5c0ba96e4174 100644 (file)
--- a/src/bin/pg_resetwal/t/001_basic.pl
+++ b/src/bin/pg_resetwal/t/001_basic.pl
@@ -173,6 +173,12 @@ command_fails_like(
        qr/must be greater than/,
        'fails with -x value too small');
 
+# --char-signedness
+command_fails_like(
+       [ 'pg_resetwal', '--char-signedness', 'foo', $node->data_dir ],
+       qr/error: invalid argument for option --char-signedness/,
+       'fails with incorrect --char-signedness option');
+
 # run with control override options
 
 my $out = (run_command([ 'pg_resetwal', '--dry-run', $node->data_dir ]))[0];