Add option list to CHECKPOINT command.

This commit adds the boilerplate code for supporting a list of
options in CHECKPOINT commands.  No actual options are supported
yet, but follow-up commits will add support for MODE and
FLUSH_UNLOGGED.  While at it, this commit refactors the code for
executing CHECKPOINT commands to its own function since it's about
to become significantly larger.

Author: Christoph Berg <myon@debian.org>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Discussion: https://postgr.es/m/aDnaKTEf-0dLiEfz%40msg.df7cb.de

doc/src/sgml/ref/checkpoint.sgml

@@ -21,7 +21,9 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CHECKPOINT
+CHECKPOINT [ ( option [, ...] ) ]
+
+<phrase>where <replaceable class="parameter">option</replaceable> can be one of:</phrase>
 </synopsis>
  </refsynopsisdiv>
 
@@ -58,6 +60,13 @@ CHECKPOINT
   </para>
  </refsect1>
 
+ <refsect1>
+  <title>Parameters</title>
+
+  <para>
+  </para>
+ </refsect1>
+
  <refsect1>
   <title>Compatibility</title>
 

src/backend/parser/gram.y

@@ -2034,6 +2034,13 @@ CheckPointStmt:
 
 					$$ = (Node *) n;
 				}
+			| CHECKPOINT '(' utility_option_list ')'
+				{
+					CheckPointStmt *n = makeNode(CheckPointStmt);
+
+					$$ = (Node *) n;
+					n->options = $3;
+				}
 		;
 
 

src/backend/postmaster/checkpointer.c

@@ -42,6 +42,7 @@
 #include "access/xlog.h"
 #include "access/xlog_internal.h"
 #include "access/xlogrecovery.h"
+#include "catalog/pg_authid.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -61,6 +62,7 @@
 #include "storage/shmem.h"
 #include "storage/smgr.h"
 #include "storage/spin.h"
+#include "utils/acl.h"
 #include "utils/guc.h"
 #include "utils/memutils.h"
 #include "utils/resowner.h"
@@ -976,6 +978,35 @@ CheckpointerShmemInit(void)
 	}
 }
 
+/*
+ * ExecCheckpoint
+ *		Primary entry point for manual CHECKPOINT commands
+ *
+ * This is mainly a wrapper for RequestCheckpoint().
+ */
+void
+ExecCheckpoint(ParseState *pstate, CheckPointStmt *stmt)
+{
+	foreach_ptr(DefElem, opt, stmt->options)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unrecognized CHECKPOINT option \"%s\"", opt->defname),
+				 parser_errposition(pstate, opt->location)));
+
+	if (!has_privs_of_role(GetUserId(), ROLE_PG_CHECKPOINT))
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+		/* translator: %s is name of an SQL command (e.g., CHECKPOINT) */
+				 errmsg("permission denied to execute %s command",
+						"CHECKPOINT"),
+				 errdetail("Only roles with privileges of the \"%s\" role may execute this command.",
+						   "pg_checkpoint")));
+
+	RequestCheckpoint(CHECKPOINT_WAIT |
+					  CHECKPOINT_FAST |
+					  (RecoveryInProgress() ? 0 : CHECKPOINT_FORCE));
+}
+
 /*
  * RequestCheckpoint
  *		Called in backend processes to request a checkpoint

src/backend/tcop/utility.c

@@ -943,17 +943,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 			break;
 
 		case T_CheckPointStmt:
-			if (!has_privs_of_role(GetUserId(), ROLE_PG_CHECKPOINT))
+			ExecCheckpoint(pstate, (CheckPointStmt *) parsetree);
-				ereport(ERROR,
-						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-				/* translator: %s is name of a SQL command, eg CHECKPOINT */
-						 errmsg("permission denied to execute %s command",
-								"CHECKPOINT"),
-						 errdetail("Only roles with privileges of the \"%s\" role may execute this command.",
-								   "pg_checkpoint")));
-
-			RequestCheckpoint(CHECKPOINT_FAST | CHECKPOINT_WAIT |
-							  (RecoveryInProgress() ? 0 : CHECKPOINT_FORCE));
 			break;
 
 			/*

src/bin/psql/tab-complete.in.c

@@ -3153,6 +3153,9 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_VERSIONED_SCHEMA_QUERY(Query_for_list_of_procedures);
 	else if (Matches("CALL", MatchAny))
 		COMPLETE_WITH("(");
+/* CHECKPOINT */
+	else if (Matches("CHECKPOINT"))
+		COMPLETE_WITH("(");
 /* CLOSE */
 	else if (Matches("CLOSE"))
 		COMPLETE_WITH_QUERY_PLUS(Query_for_list_of_cursors,

src/include/nodes/parsenodes.h

@@ -4047,6 +4047,7 @@ typedef struct RefreshMatViewStmt
 typedef struct CheckPointStmt
 {
 	NodeTag		type;
+	List	   *options;		/* list of DefElem nodes */
 } CheckPointStmt;
 
 /* ----------------------

src/include/postmaster/bgwriter.h

@@ -15,6 +15,7 @@
 #ifndef _BGWRITER_H
 #define _BGWRITER_H
 
+#include "parser/parse_node.h"
 #include "storage/block.h"
 #include "storage/relfilelocator.h"
 #include "storage/smgr.h"
@@ -30,6 +31,7 @@ extern PGDLLIMPORT double CheckPointCompletionTarget;
 pg_noreturn extern void BackgroundWriterMain(const void *startup_data, size_t startup_data_len);
 pg_noreturn extern void CheckpointerMain(const void *startup_data, size_t startup_data_len);
 
+extern void ExecCheckpoint(ParseState *pstate, CheckPointStmt *stmt);
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);
 

src/test/regress/expected/stats.out

@@ -926,6 +926,12 @@ DROP TABLE test_stats_temp;
 -- Checkpoint twice: The checkpointer reports stats after reporting completion
 -- of the checkpoint. But after a second checkpoint we'll see at least the
 -- results of the first.
+--
+-- While at it, test checkpoint options.
+CHECKPOINT (WRONG);
+ERROR:  unrecognized CHECKPOINT option "wrong"
+LINE 1: CHECKPOINT (WRONG);
+                    ^
 CHECKPOINT;
 CHECKPOINT;
 SELECT num_requested > :rqst_ckpts_before FROM pg_stat_checkpointer;

src/test/regress/sql/stats.sql

@@ -439,6 +439,9 @@ DROP TABLE test_stats_temp;
 -- Checkpoint twice: The checkpointer reports stats after reporting completion
 -- of the checkpoint. But after a second checkpoint we'll see at least the
 -- results of the first.
+--
+-- While at it, test checkpoint options.
+CHECKPOINT (WRONG);
 CHECKPOINT;
 CHECKPOINT;