Introduce field tracking cached plan type in PlannedStmt

michaelpq · michaelpq · commit 719dcf3c4226 · 2025-07-24T15:41:18.000+09:00
PlannedStmt gains a new field, called CachedPlanType, able to track if a given plan tree originates from the cache and if we are dealing with a generic or custom cached plan. This field can be used for monitoring or statistical purposes, in the executor hooks, for example, based on the planned statement attached to a QueryDesc. A patch is under discussion for pg_stat_statements to provide an equivalent of the counters in pg_prepared_statements for custom and generic plans, to provide a more global view of such data, as this data is now restricted to the current session. The concept introduced in this commit is useful on its own, and has been extracted from a larger patch by the same author. Author: Sami Imseih <samimseih@gmail.com> Reviewed-by: Andrei Lepikhov <lepihov@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CAA5RZ0uFw8Y9GCFvafhC=OA8NnMqVZyzXPfv_EePOt+iv1T-qQ@mail.gmail.com
diff --git a/src/backend/commands/foreigncmds.c b/src/backend/commands/foreigncmds.c
@@ -1588,6 +1588,7 @@ ImportForeignSchema(ImportForeignSchemaStmt *stmt)
 			pstmt->utilityStmt = (Node *) cstmt;
 			pstmt->stmt_location = rs->stmt_location;
 			pstmt->stmt_len = rs->stmt_len;
+			pstmt->cached_plan_type = PLAN_CACHE_NONE;
 
 			/* Execute statement */
 			ProcessUtility(pstmt, cmd, false,
diff --git a/src/backend/commands/schemacmds.c b/src/backend/commands/schemacmds.c
@@ -215,6 +215,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString,
 		wrapper->utilityStmt = stmt;
 		wrapper->stmt_location = stmt_location;
 		wrapper->stmt_len = stmt_len;
+		wrapper->cached_plan_type = PLAN_CACHE_NONE;
 
 		/* do this step */
 		ProcessUtility(wrapper,
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c
@@ -189,6 +189,7 @@ ExecSerializePlan(Plan *plan, EState *estate)
 	pstmt->permInfos = estate->es_rteperminfos;
 	pstmt->resultRelations = NIL;
 	pstmt->appendRelations = NIL;
+	pstmt->cached_plan_type = PLAN_CACHE_NONE;
 
 	/*
 	 * Transfer only parallel-safe subplans, leaving a NULL "hole" in the list
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
@@ -582,6 +582,7 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions,
 	result->utilityStmt = parse->utilityStmt;
 	result->stmt_location = parse->stmt_location;
 	result->stmt_len = parse->stmt_len;
+	result->cached_plan_type = PLAN_CACHE_NONE;
 
 	result->jitFlags = PGJIT_NONE;
 	if (jit_enabled && jit_above_cost >= 0 &&
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
@@ -988,6 +988,7 @@ pg_plan_queries(List *querytrees, const char *query_string, int cursorOptions,
 			stmt->stmt_location = query->stmt_location;
 			stmt->stmt_len = query->stmt_len;
 			stmt->queryId = query->queryId;
+			stmt->cached_plan_type = PLAN_CACHE_NONE;
 		}
 		else
 		{
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
@@ -1234,6 +1234,7 @@ ProcessUtilitySlow(ParseState *pstate,
 							wrapper->utilityStmt = stmt;
 							wrapper->stmt_location = pstmt->stmt_location;
 							wrapper->stmt_len = pstmt->stmt_len;
+							wrapper->cached_plan_type = PLAN_CACHE_NONE;
 
 							ProcessUtility(wrapper,
 										   queryString,
@@ -1964,6 +1965,7 @@ ProcessUtilityForAlterTable(Node *stmt, AlterTableUtilityContext *context)
 	wrapper->utilityStmt = stmt;
 	wrapper->stmt_location = context->pstmt->stmt_location;
 	wrapper->stmt_len = context->pstmt->stmt_len;
+	wrapper->cached_plan_type = PLAN_CACHE_NONE;
 
 	ProcessUtility(wrapper,
 				   context->queryString,
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
@@ -1283,6 +1283,7 @@ GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
 	CachedPlan *plan = NULL;
 	List	   *qlist;
 	bool		customplan;
+	ListCell   *lc;
 
 	/* Assert caller is doing things in a sane order */
 	Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
@@ -1385,6 +1386,13 @@ GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
 		plan->is_saved = true;
 	}
 
+	foreach(lc, plan->stmt_list)
+	{
+		PlannedStmt *pstmt = (PlannedStmt *) lfirst(lc);
+
+		pstmt->cached_plan_type = customplan ? PLAN_CACHE_CUSTOM : PLAN_CACHE_GENERIC;
+	}
+
 	return plan;
 }
 
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
@@ -28,6 +28,20 @@
  * ----------------------------------------------------------------
  */
 
+/* ----------------
+ *		CachedPlanType
+ *
+ * CachedPlanType identifies whether a PlannedStmt is a cached plan, and if
+ * so, whether it is generic or custom.
+ * ----------------
+ */
+typedef enum CachedPlanType
+{
+	PLAN_CACHE_NONE = 0,		/* Not a cached plan */
+	PLAN_CACHE_GENERIC,			/* Generic cached plan */
+	PLAN_CACHE_CUSTOM,			/* Custom cached plan */
+} CachedPlanType;
+
 /* ----------------
  *		PlannedStmt node
  *
@@ -58,6 +72,9 @@ typedef struct PlannedStmt
 	/* plan identifier (can be set by plugins) */
 	int64		planId;
 
+	/* type of cached plan */
+	CachedPlanType cached_plan_type;
+
 	/* is it insert|update|delete|merge RETURNING? */
 	bool		hasReturning;
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
@@ -391,6 +391,7 @@ CachedFunctionHashEntry
 CachedFunctionHashKey
 CachedPlan
 CachedPlanSource
+CachedPlanType
 CallContext
 CallStmt
 CancelRequestPacket

Original file line number	Diff line number	Diff line change
`@@ -988,6 +988,7 @@ pg_plan_queries(List querytrees, const char query_string, int cursorOptions,`
`988`	`988`	`stmt->stmt_location = query->stmt_location;`
`989`	`989`	`stmt->stmt_len = query->stmt_len;`
`990`	`990`	`stmt->queryId = query->queryId;`
	`991`	`+ stmt->cached_plan_type = PLAN_CACHE_NONE;`
`991`	`992`	`}`
`992`	`993`	`else`
`993`	`994`	`{`