In pg_dump, dump SEQUENCE SET items in the data not pre-data section.

Represent a sequence's current value as a separate TableDataInfo dumpable
object, so that it can be dumped within the data section of the archive
rather than in pre-data.  This fixes an undesirable inconsistency between
the meanings of "--data-only" and "--section=data", and also fixes dumping
of sequences that are marked as extension configuration tables, as per a
report from Marko Kreen back in July.  The main cost is that we do one more
SQL query per sequence, but that's probably not very meaningful in most
databases.

Back-patch to 9.1, since it has the extension configuration issue even
though not the --section switch.

doc/src/sgml/ref/pg_dump.sgml

@@ -739,11 +739,11 @@ PostgreSQL documentation
           sections. The default is to dump all sections.
          </para>
          <para>
-          The data section contains actual table data as well as large-object
-          definitions.
-          Post-data items consist of definitions of indexes, triggers, rules
+          The data section contains actual table data, large-object
+          contents, and sequence values.
+          Post-data items include definitions of indexes, triggers, rules,
           and constraints other than validated check constraints.
-          Pre-data items consist of all other data definition items.
+          Pre-data items include all other data definition items.
          </para>
        </listitem>
      </varlistentry>

src/bin/pg_dump/pg_dump.c

@@ -192,6 +192,7 @@ static void dumpTable(Archive *fout, TableInfo *tbinfo);
 static void dumpTableSchema(Archive *fout, TableInfo *tbinfo);
 static void dumpAttrDef(Archive *fout, AttrDefInfo *adinfo);
 static void dumpSequence(Archive *fout, TableInfo *tbinfo);
+static void dumpSequenceData(Archive *fout, TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, IndxInfo *indxinfo);
 static void dumpConstraint(Archive *fout, ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, ConstraintInfo *coninfo);
@@ -1640,9 +1641,6 @@ makeTableDataInfo(TableInfo *tbinfo, bool oids)
 	/* Skip VIEWs (no data to dump) */
 	if (tbinfo->relkind == RELKIND_VIEW)
 		return;
-	/* Skip SEQUENCEs (handled elsewhere) */
-	if (tbinfo->relkind == RELKIND_SEQUENCE)
-		return;
 	/* Skip FOREIGN TABLEs (no data to dump) */
 	if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
 		return;
@@ -7318,6 +7316,9 @@ dumpDumpableObject(Archive *fout, DumpableObject *dobj)
 			dumpCast(fout, (CastInfo *) dobj);
 			break;
 		case DO_TABLE_DATA:
+			if (((TableDataInfo *) dobj)->tdtable->relkind == RELKIND_SEQUENCE)
+				dumpSequenceData(fout, (TableDataInfo *) dobj);
+			else
 				dumpTableData(fout, (TableDataInfo *) dobj);
 			break;
 		case DO_DUMMY_TYPE:
@@ -12226,13 +12227,13 @@ collectSecLabels(Archive *fout, SecLabelItem **items)
 static void
 dumpTable(Archive *fout, TableInfo *tbinfo)
 {
-	if (tbinfo->dobj.dump)
+	if (tbinfo->dobj.dump && !dataOnly)
 	{
 		char	   *namecopy;
 
 		if (tbinfo->relkind == RELKIND_SEQUENCE)
 			dumpSequence(fout, tbinfo);
-		else if (!dataOnly)
+		else
 			dumpTableSchema(fout, tbinfo);
 
 		/* Handle the ACL here */
@@ -13347,20 +13348,22 @@ findLastBuiltinOid_V70(Archive *fout)
 	return last_oid;
 }
 
+/*
+ * dumpSequence
+ *	  write the declaration (not data) of one user-defined sequence
+ */
 static void
 dumpSequence(Archive *fout, TableInfo *tbinfo)
 {
 	PGresult   *res;
 	char	   *startv,
-			   *last,
 			   *incby,
 			   *maxv = NULL,
 			   *minv = NULL,
 			   *cache;
 	char		bufm[100],
 				bufx[100];
-	bool		cycled,
-				called;
+	bool		cycled;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -13375,7 +13378,7 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, last_value, increment_by, "
+						  "start_value, increment_by, "
 				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
 				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
 						  "     ELSE max_value "
@@ -13384,7 +13387,7 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
 						  "     ELSE min_value "
 						  "END AS min_value, "
-						  "cache_value, is_cycled, is_called from %s",
+						  "cache_value, is_cycled FROM %s",
 						  bufx, bufm,
 						  fmtId(tbinfo->dobj.name));
 	}
@@ -13392,7 +13395,7 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, last_value, increment_by, "
+						  "0 AS start_value, increment_by, "
 				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
 				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
 						  "     ELSE max_value "
@@ -13401,7 +13404,7 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
 						  "     ELSE min_value "
 						  "END AS min_value, "
-						  "cache_value, is_cycled, is_called from %s",
+						  "cache_value, is_cycled FROM %s",
 						  bufx, bufm,
 						  fmtId(tbinfo->dobj.name));
 	}
@@ -13428,31 +13431,16 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 #endif
 
 	startv = PQgetvalue(res, 0, 1);
-	last = PQgetvalue(res, 0, 2);
-	incby = PQgetvalue(res, 0, 3);
+	incby = PQgetvalue(res, 0, 2);
+	if (!PQgetisnull(res, 0, 3))
+		maxv = PQgetvalue(res, 0, 3);
 	if (!PQgetisnull(res, 0, 4))
-		maxv = PQgetvalue(res, 0, 4);
-	if (!PQgetisnull(res, 0, 5))
-		minv = PQgetvalue(res, 0, 5);
-	cache = PQgetvalue(res, 0, 6);
-	cycled = (strcmp(PQgetvalue(res, 0, 7), "t") == 0);
-	called = (strcmp(PQgetvalue(res, 0, 8), "t") == 0);
+		minv = PQgetvalue(res, 0, 4);
+	cache = PQgetvalue(res, 0, 5);
+	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
 
 	/*
-	 * The logic we use for restoring sequences is as follows:
-	 *
-	 * Add a CREATE SEQUENCE statement as part of a "schema" dump (use
-	 * last_val for start if called is false, else use min_val for start_val).
-	 * Also, if the sequence is owned by a column, add an ALTER SEQUENCE OWNED
-	 * BY command for it.
-	 *
-	 * Add a 'SETVAL(seq, last_val, iscalled)' as part of a "data" dump.
-	 */
-	if (!dataOnly)
-	{
-		/*
-		 * DROP must be fully qualified in case same name appears in
-		 * pg_catalog
+	 * DROP must be fully qualified in case same name appears in pg_catalog
 	 */
 	appendPQExpBuffer(delqry, "DROP SEQUENCE %s.",
 					  fmtId(tbinfo->dobj.namespace->dobj.name));
@@ -13475,16 +13463,6 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
-		else
-		{
-			/*
-			 * Versions before 8.4 did not remember the true start value.  If
-			 * is_called is false then the sequence has never been incremented
-			 * so we can use last_val.	Otherwise punt and let it default.
-			 */
-			if (!called)
-				appendPQExpBuffer(query, "    START WITH %s\n", last);
-		}
 
 	appendPQExpBuffer(query, "    INCREMENT BY %s\n", incby);
 
@@ -13523,16 +13501,16 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 				 NULL, NULL);
 
 	/*
-		 * If the sequence is owned by a table column, emit the ALTER for it
-		 * as a separate TOC entry immediately following the sequence's own
-		 * entry.  It's OK to do this rather than using full sorting logic,
-		 * because the dependency that tells us it's owned will have forced
-		 * the table to be created first.  We can't just include the ALTER in
-		 * the TOC entry because it will fail if we haven't reassigned the
-		 * sequence owner to match the table's owner.
+	 * If the sequence is owned by a table column, emit the ALTER for it as a
+	 * separate TOC entry immediately following the sequence's own entry.
+	 * It's OK to do this rather than using full sorting logic, because the
+	 * dependency that tells us it's owned will have forced the table to be
+	 * created first.  We can't just include the ALTER in the TOC entry
+	 * because it will fail if we haven't reassigned the sequence owner to
+	 * match the table's owner.
 	 *
-		 * We need not schema-qualify the table reference because both
-		 * sequence and table must be in the same schema.
+	 * We need not schema-qualify the table reference because both sequence
+	 * and table must be in the same schema.
 	 */
 	if (OidIsValid(tbinfo->owning_tab))
 	{
@@ -13567,10 +13545,48 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	dumpSecLabel(fout, labelq->data,
 				 tbinfo->dobj.namespace->dobj.name, tbinfo->rolname,
 				 tbinfo->dobj.catId, 0, tbinfo->dobj.dumpId);
-	}
 
-	if (!schemaOnly)
+	PQclear(res);
+
+	destroyPQExpBuffer(query);
+	destroyPQExpBuffer(delqry);
+	destroyPQExpBuffer(labelq);
+}
+
+/*
+ * dumpSequenceData
+ *	  write the data of one user-defined sequence
+ */
+static void
+dumpSequenceData(Archive *fout, TableDataInfo *tdinfo)
+{
+	TableInfo  *tbinfo = tdinfo->tdtable;
+	PGresult   *res;
+	char	   *last;
+	bool		called;
+	PQExpBuffer query = createPQExpBuffer();
+
+	/* Make sure we are in proper schema */
+	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
+
+	appendPQExpBuffer(query,
+					  "SELECT last_value, is_called FROM %s",
+					  fmtId(tbinfo->dobj.name));
+
+	res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
+
+	if (PQntuples(res) != 1)
 	{
+		write_msg(NULL, ngettext("query to get data of sequence \"%s\" returned %d row (expected 1)\n",
+								 "query to get data of sequence \"%s\" returned %d rows (expected 1)\n",
+								 PQntuples(res)),
+				  tbinfo->dobj.name, PQntuples(res));
+		exit_nicely(1);
+	}
+
+	last = PQgetvalue(res, 0, 0);
+	called = (strcmp(PQgetvalue(res, 0, 1), "t") == 0);
+
 	resetPQExpBuffer(query);
 	appendPQExpBuffer(query, "SELECT pg_catalog.setval(");
 	appendStringLiteralAH(query, fmtId(tbinfo->dobj.name), fout);
@@ -13582,17 +13598,14 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 				 tbinfo->dobj.namespace->dobj.name,
 				 NULL,
 				 tbinfo->rolname,
-					 false, "SEQUENCE SET", SECTION_PRE_DATA,
+				 false, "SEQUENCE SET", SECTION_DATA,
 				 query->data, "", NULL,
 				 &(tbinfo->dobj.dumpId), 1,
 				 NULL, NULL);
-	}
 
 	PQclear(res);
 
 	destroyPQExpBuffer(query);
-	destroyPQExpBuffer(delqry);
-	destroyPQExpBuffer(labelq);
 }
 
 static void