提交: 69736277118038029051a2173e1effc400c8dca5 - amalsyah12 (git)

firtst release

Commit MetaInfo

• 修订版: 69736277118038029051a2173e1effc400c8dca5 (tree)
• 时间: 2019-01-07 19:07:39
• 作者: Kyotaro Horiguchi <horiguchi.kyotaro@lab....>
• Commiter: Kyotaro Horiguchi

Log Message

Support prepared statements on extended protocol

However pg_hint_plan doesn't fully consider the extended protocol,
commit 64ab47b accidentially broke the case where an analyzed prepared
statement is executed on extended protocol. This patch fixes that only
for the hints-in-comment case. Hint-table still doesn't work in the
case since query-normalization needs Query, which is not available in
planner_hook.

更改概述

• modified: pg_hint_plan.c

差异

--- a/pg_hint_plan.c
+++ b/pg_hint_plan.c
@@ -198,6 +198,14 @@ static unsigned int msgqno = 0;
 static char qnostr[32];
 static const char *current_hint_str = NULL;
 
+/*
+ * However we usually take a hint stirng in post_parse_analyze_hook, we still
+ * need to do so in planner_hook when client starts query execution from the
+ * bind message on a prepared query. This variable prevent duplicate and
+ * sometimes harmful hint string retrieval.
+ */
+static bool current_hint_retrieved = false;
+
 /* common data for all hints. */
 struct Hint
 {
@@ -347,6 +355,10 @@ static void push_hint(HintState *hstate);
 static void pop_hint(void);
 
 static void pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query);
+static void pg_hint_plan_ProcessUtility(Node *parsetree,
+					const char *queryString,
+					ProcessUtilityContext context, ParamListInfo params,
+					DestReceiver *dest, char *completionTag);
 static PlannedStmt *pg_hint_plan_planner(Query *parse, int cursorOptions,
 										 ParamListInfo boundParams);
 static void pg_hint_plan_get_relation_info(PlannerInfo *root,
@@ -482,6 +494,7 @@ static post_parse_analyze_hook_type prev_post_parse_analyze_hook = NULL;
 static planner_hook_type prev_planner = NULL;
 static get_relation_info_hook_type prev_get_relation_info = NULL;
 static join_search_hook_type prev_join_search = NULL;
+static ProcessUtility_hook_type prev_ProcessUtility_hook = NULL;
 
 /* Hold reference to currently active hint */
 static HintState *current_hint = NULL;
@@ -606,6 +619,8 @@ _PG_init(void)
 	get_relation_info_hook = pg_hint_plan_get_relation_info;
 	prev_join_search = join_search_hook;
 	join_search_hook = pg_hint_plan_join_search;
+	prev_ProcessUtility_hook = ProcessUtility_hook;
+	ProcessUtility_hook = pg_hint_plan_ProcessUtility;
 
 	/* setup PL/pgSQL plugin hook */
 	var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
@@ -628,6 +643,7 @@ _PG_fini(void)
 	planner_hook = prev_planner;
 	get_relation_info_hook = prev_get_relation_info;
 	join_search_hook = prev_join_search;
+	ProcessUtility_hook = prev_ProcessUtility_hook;
 
 	/* uninstall PL/pgSQL plugin hook */
 	var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
@@ -1660,17 +1676,15 @@ get_query_string(ParseState *pstate, Query *query, Query **jumblequery)
 	/*
 	 * If debug_query_string is set, it is the top level statement. But in some
 	 * cases we reach here with debug_query_string set NULL for example in the
-	 * case of DESCRIBE message handling. We may still see a candidate
-	 * top-level query in pstate in the case.
+	 * case of DESCRIBE message handling or EXECUTE command. We may still see a
+	 * candidate top-level query in pstate in the case.
 	 */
-	if (!p)
-	{
-		/* We don't see a query string, return NULL */
-		if (!pstate->p_sourcetext)
-			return NULL;
-
+	if (!p && pstate)
 		p = pstate->p_sourcetext;
-	}
+
+	/* We don't see a query string, return NULL */
+	if (!p)
+		return NULL;
 
 	if (jumblequery != NULL)
 		*jumblequery = query;
@@ -1754,9 +1768,12 @@ get_query_string(ParseState *pstate, Query *query, Query **jumblequery)
 		if (jumblequery)
 			*jumblequery = target_query;
 	}
-
-	/* Return NULL if the pstate is not identical to the top-level query */
-	else if (strcmp(pstate->p_sourcetext, p) != 0)
+	/*
+	 * Return NULL if pstate is not of top-level query.  We don't need this
+	 * when jumble info is not requested or cannot do this when pstate is NULL.
+	 */
+	else if (!jumblequery && pstate && pstate->p_sourcetext != p &&
+			 strcmp(pstate->p_sourcetext, p) != 0)
 		p = NULL;
 
 	return p;
@@ -2438,24 +2455,25 @@ pop_hint(void)
 }
 
 /*
- * Retrieve and store a hint string from given query or from the hint table.
- * If we are using the hint table, the query string is needed to be normalized.
- * However, ParseState, which is not available in planner_hook, is required to
- * check if the query tree (Query) is surely corresponding to the target query.
+ * Retrieve and store hint string from given query or from the hint table.
  */
 static void
-pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
+get_current_hint_string(ParseState *pstate, Query *query)
 {
 	const char *query_str;
 	MemoryContext	oldcontext;
 
-	if (prev_post_parse_analyze_hook)
-		prev_post_parse_analyze_hook(pstate, query);
-
 	/* do nothing under hint table search */
 	if (hint_inhibit_level > 0)
 		return;
 
+	/* We alredy have one, don't parse it again. */
+	if (current_hint_retrieved)
+		return;
+
+	/* Don't parse the current query hereafter */
+	current_hint_retrieved = true;
+
 	if (!pg_hint_plan_enable_hint)
 	{
 		if (current_hint_str)
@@ -2496,8 +2514,8 @@ pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
 		if (jumblequery)
 		{
 			/*
-			 * XXX: normalizing code is copied from pg_stat_statements.c, so be
-			 * careful to PostgreSQL's version up.
+			 * XXX: normalization code is copied from pg_stat_statements.c.
+			 * Make sure to keep up-to-date with it.
 			 */
 			jstate.jumble = (unsigned char *) palloc(JUMBLE_SIZE);
 			jstate.jumble_len = 0;
@@ -2573,8 +2591,8 @@ pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
 	{
 		/*
 		 * get hints from the comment. However we may have the same query
-		 * string with the previous call, but just retrieving hints is expected
-		 * to be faster than checking for identicalness before retrieval.
+		 * string with the previous call, but the extra comparison seems no
+		 * use..
 		 */
 		if (current_hint_str)
 			pfree((void *)current_hint_str);
@@ -2606,6 +2624,40 @@ pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
 }
 
 /*
+ * Retrieve hint string from the current query.
+ */
+static void
+pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
+{
+	if (prev_post_parse_analyze_hook)
+		prev_post_parse_analyze_hook(pstate, query);
+
+	/* always retrieve hint from the top-level query string */
+	if (plpgsql_recurse_level == 0)
+		current_hint_retrieved = false;
+
+	get_current_hint_string(pstate, query);
+}
+
+/*
+ * We need to reset current_hint_retrieved flag always when a command execution
+ * is finished. This is true even for a pure utility command that doesn't
+ * involve planning phase.
+ */
+static void
+pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
+					ProcessUtilityContext context, ParamListInfo params,
+					DestReceiver *dest, char *completionTag)
+{
+	if (prev_ProcessUtility_hook)
+		prev_ProcessUtility_hook(parsetree, queryString, context, params,
+								 dest, completionTag);
+
+	if (plpgsql_recurse_level == 0)
+		current_hint_retrieved = false;
+}
+
+/*
  * Read and set up hint information
  */
 static PlannedStmt *
@@ -2651,6 +2703,14 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 		MemoryContextSwitchTo(oldcontext);
 	}
 
+	/*
+	 * Query execution in extended protocol can be started without the analyze
+	 * phase. In the case retrieve hint string here.
+	 */
+	if (!current_hint_str)
+		get_current_hint_string(NULL, parse);
+
+	/* No hint, go the normal way */
 	if (!current_hint_str)
 		goto standard_planner_proc;
 
@@ -2719,6 +2779,17 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 	}
 	PG_END_TRY();
 
+
+	/*
+	 * current_hint_str is useless after planning of the top-level query.
+	 */
+	if (plpgsql_recurse_level < 1 && current_hint_str)
+	{
+		pfree((void *)current_hint_str);
+		current_hint_str = NULL;
+		current_hint_retrieved = false;
+	}
+
 	/* Print hint in debug mode. */
 	if (debug_level == 1)
 		HintStateDump(current_hint);