Andres,

>> I think the code needs a few clarifying comments around this, but
>> otherwise seems good.  Not restarting the timeout in those cases
>> obviously isn't entirely "perfect"/"correct", but a tradeoff - the
>> comments should note that.
>> 
>> Tatsuo-san, do you want to change those, and push?  I can otherwise.
> 
> Andres,
> 
> If you don't mind, could you please fix the comments and push it.

I have changed the comments as you suggested. If it's ok, I can push
the patch myself (today I have time to work on this).

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index a2282058..1fd93359 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -149,6 +149,11 @@ static bool doing_extended_query_message = false;
 static bool ignore_till_sync = false;
 
 /*
+ * Flag to keep track of whether we have started statement timeout timer.
+ */
+static bool stmt_timer_started = false;
+
+/*
  * If an unnamed prepared statement exists, it's stored here.
  * We keep it separate from the hashtable kept by commands/prepare.c
  * in order to reduce overhead for short-lived queries.
@@ -188,6 +193,8 @@ static bool IsTransactionStmtList(List *pstmts);
 static void drop_unnamed_stmt(void);
 static void SigHupHandler(SIGNAL_ARGS);
 static void log_disconnections(int code, Datum arg);
+static void enable_statement_timeout(void);
+static void disable_statement_timeout(void);
 
 
 /* ----------------------------------------------------------------
@@ -1239,6 +1246,15 @@ exec_parse_message(const char *query_string,	/* string to execute */
 	start_xact_command();
 
 	/*
+	 * Set statement timeout running if it's not already set. The timer will
+	 * be reset in a subsequent execute message. Ideally the timer should be
+	 * reset in this function so that each parse/bind/execute message catches
+	 * the timeout, but it needs gettimeofday() call for each, which is too
+	 * expensive.
+	 */
+	enable_statement_timeout();
+
+	/*
 	 * Switch to appropriate context for constructing parsetrees.
 	 *
 	 * We have two strategies depending on whether the prepared statement is
@@ -1526,6 +1542,15 @@ exec_bind_message(StringInfo input_message)
 	 */
 	start_xact_command();
 
+	/*
+	 * Set statement timeout running if it's not already set. The timer will
+	 * be reset in a subsequent execute message. Ideally the timer should be
+	 * reset in this function so that each parse/bind/execute message catches
+	 * the timeout, but it needs gettimeofday() call for each, which is too
+	 * expensive.
+	 */
+	enable_statement_timeout();
+
 	/* Switch back to message context */
 	MemoryContextSwitchTo(MessageContext);
 
@@ -1942,6 +1967,11 @@ exec_execute_message(const char *portal_name, long max_rows)
 	start_xact_command();
 
 	/*
+	 * Set statement timeout running if it's not already set.
+	 */
+	enable_statement_timeout();
+
+	/*
 	 * If we re-issue an Execute protocol request against an existing portal,
 	 * then we are only fetching more rows rather than completely re-executing
 	 * the query from the start. atStart is never reset for a v3 portal, so we
@@ -2014,6 +2044,11 @@ exec_execute_message(const char *portal_name, long max_rows)
 			 * those that start or end a transaction block.
 			 */
 			CommandCounterIncrement();
+
+			/*
+			 * We need to reset statement timeout if already set.
+			 */
+			disable_statement_timeout();
 		}
 
 		/* Send appropriate CommandComplete to client */
@@ -2443,14 +2478,10 @@ start_xact_command(void)
 	{
 		StartTransactionCommand();
 
-		/* Set statement timeout running, if any */
-		/* NB: this mustn't be enabled until we are within an xact */
-		if (StatementTimeout > 0)
-			enable_timeout_after(STATEMENT_TIMEOUT, StatementTimeout);
-		else
-			disable_timeout(STATEMENT_TIMEOUT, false);
-
 		xact_started = true;
+
+		/* Set statement timeout running, if any */
+		enable_statement_timeout();
 	}
 }
 
@@ -2460,7 +2491,7 @@ finish_xact_command(void)
 	if (xact_started)
 	{
 		/* Cancel any active statement timeout before committing */
-		disable_timeout(STATEMENT_TIMEOUT, false);
+		disable_statement_timeout();
 
 		CommitTransactionCommand();
 
@@ -4511,3 +4542,53 @@ log_disconnections(int code, Datum arg)
 					port->user_name, port->database_name, port->remote_host,
 				  port->remote_port[0] ? " port=" : "", port->remote_port)));
 }
+
+/*
+ * Set statement timeout if any.
+ */
+static void
+enable_statement_timeout(void)
+{
+	if (!stmt_timer_started)
+	{
+		if (StatementTimeout > 0)
+		{
+
+			/*
+			 * Sanity check
+			 */
+			if (!xact_started)
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("Transaction must have been already started to set statement timeout")));
+			}
+
+			ereport(DEBUG3,
+					(errmsg_internal("Set statement timeout")));
+
+			enable_timeout_after(STATEMENT_TIMEOUT, StatementTimeout);
+			stmt_timer_started = true;
+		}
+		else
+			disable_timeout(STATEMENT_TIMEOUT, false);
+	}
+}
+
+/*
+ * Reset statement timeout if any.
+ */
+static void
+disable_statement_timeout(void)
+{
+	if (stmt_timer_started)
+	{
+		ereport(DEBUG3,
+					(errmsg_internal("Disable statement timeout")));
+
+		/* Cancel any active statement timeout */
+		disable_timeout(STATEMENT_TIMEOUT, false);
+
+		stmt_timer_started = false;
+	}
+}
-- 
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