Rename OverrideSearchPath to SearchPathMatcher.

The previous commit removed the "override" APIs.  Surviving APIs facilitate
plancache.c to snapshot search_path and test whether the current value equals
a remembered snapshot.

Aleksander Alekseev.  Reported by Alexander Lakhin and Noah Misch.

Discussion: https://postgr.es/m/8ffb4650-52c4-6a81-38fc-8f99be981130@gmail.com

src/backend/catalog/namespace.c

@@ -3374,16 +3374,16 @@ SetTempNamespaceState(Oid tempNamespaceId, Oid tempToastNamespaceId)
 
 
 /*
- * GetOverrideSearchPath - fetch current search path definition.
+ * GetSearchPathMatcher - fetch current search path definition.
  *
  * The result structure is allocated in the specified memory context
  * (which might or might not be equal to CurrentMemoryContext); but any
  * junk created by revalidation calculations will be in CurrentMemoryContext.
  */
-OverrideSearchPath *
-GetOverrideSearchPath(MemoryContext context)
+SearchPathMatcher *
+GetSearchPathMatcher(MemoryContext context)
 {
-	OverrideSearchPath *result;
+	SearchPathMatcher *result;
 	List	   *schemas;
 	MemoryContext oldcxt;
 
@@ -3391,7 +3391,7 @@ GetOverrideSearchPath(MemoryContext context)
 
 	oldcxt = MemoryContextSwitchTo(context);
 
-	result = (OverrideSearchPath *) palloc0(sizeof(OverrideSearchPath));
+	result = (SearchPathMatcher *) palloc0(sizeof(SearchPathMatcher));
 	schemas = list_copy(activeSearchPath);
 	while (schemas && linitial_oid(schemas) != activeCreationNamespace)
 	{
@@ -3413,16 +3413,16 @@ GetOverrideSearchPath(MemoryContext context)
 }
 
 /*
- * CopyOverrideSearchPath - copy the specified OverrideSearchPath.
+ * CopySearchPathMatcher - copy the specified SearchPathMatcher.
  *
  * The result structure is allocated in CurrentMemoryContext.
  */
-OverrideSearchPath *
-CopyOverrideSearchPath(OverrideSearchPath *path)
+SearchPathMatcher *
+CopySearchPathMatcher(SearchPathMatcher *path)
 {
-	OverrideSearchPath *result;
+	SearchPathMatcher *result;
 
-	result = (OverrideSearchPath *) palloc(sizeof(OverrideSearchPath));
+	result = (SearchPathMatcher *) palloc(sizeof(SearchPathMatcher));
 	result->schemas = list_copy(path->schemas);
 	result->addCatalog = path->addCatalog;
 	result->addTemp = path->addTemp;
@@ -3432,7 +3432,7 @@ CopyOverrideSearchPath(OverrideSearchPath *path)
 }
 
 /*
- * OverrideSearchPathMatchesCurrent - does path match current setting?
+ * SearchPathMatchesCurrentEnvironment - does path match current environment?
  *
  * This is tested over and over in some common code paths, and in the typical
  * scenario where the active search path seldom changes, it'll always succeed.
@@ -3440,7 +3440,7 @@ CopyOverrideSearchPath(OverrideSearchPath *path)
  * whenever the active search path changes.
  */
 bool
-OverrideSearchPathMatchesCurrent(OverrideSearchPath *path)
+SearchPathMatchesCurrentEnvironment(SearchPathMatcher *path)
 {
 	ListCell   *lc,
 			   *lcp;

src/backend/utils/cache/plancache.c

@@ -407,7 +407,7 @@ CompleteCachedPlan(CachedPlanSource *plansource,
 		 * one-shot plans; and we *must* skip this for transaction control
 		 * commands, because this could result in catalog accesses.
 		 */
-		plansource->search_path = GetOverrideSearchPath(querytree_context);
+		plansource->search_path = GetSearchPathMatcher(querytree_context);
 	}
 
 	/*
@@ -586,7 +586,7 @@ RevalidateCachedQuery(CachedPlanSource *plansource,
 	if (plansource->is_valid)
 	{
 		Assert(plansource->search_path != NULL);
-		if (!OverrideSearchPathMatchesCurrent(plansource->search_path))
+		if (!SearchPathMatchesCurrentEnvironment(plansource->search_path))
 		{
 			/* Invalidate the querytree and generic plan */
 			plansource->is_valid = false;
@@ -759,7 +759,7 @@ RevalidateCachedQuery(CachedPlanSource *plansource,
 	 * not generate much extra cruft either, since almost certainly the path
 	 * is already valid.)
 	 */
-	plansource->search_path = GetOverrideSearchPath(querytree_context);
+	plansource->search_path = GetSearchPathMatcher(querytree_context);
 
 	MemoryContextSwitchTo(oldcxt);
 
@@ -1326,7 +1326,7 @@ CachedPlanAllowsSimpleValidityCheck(CachedPlanSource *plansource,
 	Assert(plan->is_valid);
 	Assert(plan == plansource->gplan);
 	Assert(plansource->search_path != NULL);
-	Assert(OverrideSearchPathMatchesCurrent(plansource->search_path));
+	Assert(SearchPathMatchesCurrentEnvironment(plansource->search_path));
 
 	/* We don't support oneshot plans here. */
 	if (plansource->is_oneshot)
@@ -1449,7 +1449,7 @@ CachedPlanIsSimplyValid(CachedPlanSource *plansource, CachedPlan *plan,
 
 	/* Is the search_path still the same as when we made it? */
 	Assert(plansource->search_path != NULL);
-	if (!OverrideSearchPathMatchesCurrent(plansource->search_path))
+	if (!SearchPathMatchesCurrentEnvironment(plansource->search_path))
 		return false;
 
 	/* It's still good.  Bump refcount if requested. */
@@ -1565,7 +1565,7 @@ CopyCachedPlan(CachedPlanSource *plansource)
 	newsource->relationOids = copyObject(plansource->relationOids);
 	newsource->invalItems = copyObject(plansource->invalItems);
 	if (plansource->search_path)
-		newsource->search_path = CopyOverrideSearchPath(plansource->search_path);
+		newsource->search_path = CopySearchPathMatcher(plansource->search_path);
 	newsource->query_context = querytree_context;
 	newsource->rewriteRoleId = plansource->rewriteRoleId;
 	newsource->rewriteRowSecurity = plansource->rewriteRowSecurity;

src/include/catalog/namespace.h

@@ -49,19 +49,19 @@ typedef enum TempNamespaceStatus
 } TempNamespaceStatus;
 
 /*
- *	Structure for xxxOverrideSearchPath functions
+ *	Structure for xxxSearchPathMatcher functions
  *
  * The generation counter is private to namespace.c and shouldn't be touched
  * by other code.  It can be initialized to zero if necessary (that means
  * "not known equal to the current active path").
  */
-typedef struct OverrideSearchPath
+typedef struct SearchPathMatcher
 {
 	List	   *schemas;		/* OIDs of explicitly named schemas */
 	bool		addCatalog;		/* implicitly prepend pg_catalog? */
 	bool		addTemp;		/* implicitly prepend temp schema? */
 	uint64		generation;		/* for quick detection of equality to active */
-} OverrideSearchPath;
+} SearchPathMatcher;
 
 /*
  * Option flag bits for RangeVarGetRelidExtended().
@@ -164,9 +164,9 @@ extern void SetTempNamespaceState(Oid tempNamespaceId,
 								  Oid tempToastNamespaceId);
 extern void ResetTempTableNamespace(void);
 
-extern OverrideSearchPath *GetOverrideSearchPath(MemoryContext context);
-extern OverrideSearchPath *CopyOverrideSearchPath(OverrideSearchPath *path);
-extern bool OverrideSearchPathMatchesCurrent(OverrideSearchPath *path);
+extern SearchPathMatcher *GetSearchPathMatcher(MemoryContext context);
+extern SearchPathMatcher *CopySearchPathMatcher(SearchPathMatcher *path);
+extern bool SearchPathMatchesCurrentEnvironment(SearchPathMatcher *path);
 
 extern Oid	get_collation_oid(List *collname, bool missing_ok);
 extern Oid	get_conversion_oid(List *conname, bool missing_ok);

src/include/utils/plancache.h

@@ -111,7 +111,7 @@ typedef struct CachedPlanSource
 	List	   *query_list;		/* list of Query nodes, or NIL if not valid */
 	List	   *relationOids;	/* OIDs of relations the queries depend on */
 	List	   *invalItems;		/* other dependencies, as PlanInvalItems */
-	struct OverrideSearchPath *search_path; /* search_path used for parsing
+	struct SearchPathMatcher *search_path;	/* search_path used for parsing
 											 * and planning */
 	MemoryContext query_context;	/* context holding the above, or NULL */
 	Oid			rewriteRoleId;	/* Role ID we did rewriting for */

src/tools/pgindent/typedefs.list

@@ -1686,7 +1686,6 @@ OuterJoinClauseInfo
 OutputPluginCallbacks
 OutputPluginOptions
 OutputPluginOutputType
-OverrideSearchPath
 OverridingKind
 PACE_HEADER
 PACL
@@ -2463,6 +2462,7 @@ ScanState
 ScanTypeControl
 ScannerCallbackState
 SchemaQuery
+SearchPathMatcher
 SecBuffer
 SecBufferDesc
 SecLabelItem