Minor cleanup/optimization in pg_dump.

In the wake of commits 05649b8 and 5209c0b, findComments() and
findSecLabels() no longer use their "Archive *fout" arguments,
so get rid of those.

While doing that, I noticed that there's no very good reason why
dumpCompositeTypeColComments() should be doing its own query to fetch
the column names of the composite type, when the calling function has
just fetched the same data.  Tweak it to use that query result.  This
probably doesn't save a lot for most people, because since 5209c0b
we won't get into this code at all unless the composite type has at
least one comment.  Nonetheless, it's a wasted query.

Author: tglsfdc

src/bin/pg_dump/pg_dump.c

@@ -184,14 +184,12 @@ static inline void dumpComment(Archive *fout, const char *type,
 							   const char *name, const char *namespace,
 							   const char *owner, CatalogId catalogId,
 							   int subid, DumpId dumpId);
-static int	findComments(Archive *fout, Oid classoid, Oid objoid,
-						 CommentItem **items);
+static int	findComments(Oid classoid, Oid objoid, CommentItem **items);
 static void collectComments(Archive *fout);
 static void dumpSecLabel(Archive *fout, const char *type, const char *name,
 						 const char *namespace, const char *owner,
 						 CatalogId catalogId, int subid, DumpId dumpId);
-static int	findSecLabels(Archive *fout, Oid classoid, Oid objoid,
-						  SecLabelItem **items);
+static int	findSecLabels(Oid classoid, Oid objoid, SecLabelItem **items);
 static void collectSecLabels(Archive *fout);
 static void dumpDumpableObject(Archive *fout, DumpableObject *dobj);
 static void dumpNamespace(Archive *fout, const NamespaceInfo *nspinfo);
@@ -203,7 +201,8 @@ static void dumpRangeType(Archive *fout, const TypeInfo *tyinfo);
 static void dumpUndefinedType(Archive *fout, const TypeInfo *tyinfo);
 static void dumpDomain(Archive *fout, const TypeInfo *tyinfo);
 static void dumpCompositeType(Archive *fout, const TypeInfo *tyinfo);
-static void dumpCompositeTypeColComments(Archive *fout, const TypeInfo *tyinfo);
+static void dumpCompositeTypeColComments(Archive *fout, const TypeInfo *tyinfo,
+										 PGresult *res);
 static void dumpShellType(Archive *fout, const ShellTypeInfo *stinfo);
 static void dumpProcLang(Archive *fout, const ProcLangInfo *plang);
 static void dumpFunc(Archive *fout, const FuncInfo *finfo);
@@ -9154,7 +9153,7 @@ dumpCommentExtended(Archive *fout, const char *type,
 	}
 
 	/* Search for comments associated with catalogId, using table */
-	ncomments = findComments(fout, catalogId.tableoid, catalogId.oid,
+	ncomments = findComments(catalogId.tableoid, catalogId.oid,
 							 &comments);
 
 	/* Is there one matching the subid? */
@@ -9260,8 +9259,7 @@ dumpTableComment(Archive *fout, const TableInfo *tbinfo,
 		return;
 
 	/* Search for comments associated with relation, using table */
-	ncomments = findComments(fout,
-							 tbinfo->dobj.catId.tableoid,
+	ncomments = findComments(tbinfo->dobj.catId.tableoid,
 							 tbinfo->dobj.catId.oid,
 							 &comments);
 
@@ -9341,8 +9339,7 @@ dumpTableComment(Archive *fout, const TableInfo *tbinfo,
  * one search.
  */
 static int
-findComments(Archive *fout, Oid classoid, Oid objoid,
-			 CommentItem **items)
+findComments(Oid classoid, Oid objoid, CommentItem **items)
 {
 	CommentItem *middle = NULL;
 	CommentItem *low;
@@ -10740,7 +10737,7 @@ dumpCompositeType(Archive *fout, const TypeInfo *tyinfo)
 		 */
 		appendPQExpBufferStr(query,
 							 "PREPARE dumpCompositeType(pg_catalog.oid) AS\n"
-							 "SELECT a.attname, "
+							 "SELECT a.attname, a.attnum, "
 							 "pg_catalog.format_type(a.atttypid, a.atttypmod) AS atttypdefn, "
 							 "a.attlen, a.attalign, a.attisdropped, "
 							 "CASE WHEN a.attcollation <> at.typcollation "
@@ -10891,92 +10888,71 @@ dumpCompositeType(Archive *fout, const TypeInfo *tyinfo)
 				tyinfo->dobj.namespace->dobj.name,
 				tyinfo->rolname, &tyinfo->dacl);
 
+	/* Dump any per-column comments */
+	if (tyinfo->dobj.dump & DUMP_COMPONENT_COMMENT)
+		dumpCompositeTypeColComments(fout, tyinfo, res);
+
 	PQclear(res);
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(dropped);
 	destroyPQExpBuffer(delq);
 	destroyPQExpBuffer(query);
 	free(qtypname);
 	free(qualtypname);
-
-	/* Dump any per-column comments */
-	if (tyinfo->dobj.dump & DUMP_COMPONENT_COMMENT)
-		dumpCompositeTypeColComments(fout, tyinfo);
 }
 
 /*
  * dumpCompositeTypeColComments
  *	  writes out to fout the queries to recreate comments on the columns of
- *	  a user-defined stand-alone composite type
+ *	  a user-defined stand-alone composite type.
+ *
+ * The caller has already made a query to collect the names and attnums
+ * of the type's columns, so we just pass that result into here rather
+ * than reading them again.
  */
 static void
-dumpCompositeTypeColComments(Archive *fout, const TypeInfo *tyinfo)
+dumpCompositeTypeColComments(Archive *fout, const TypeInfo *tyinfo,
+							 PGresult *res)
 {
 	CommentItem *comments;
 	int			ncomments;
-	PGresult   *res;
 	PQExpBuffer query;
 	PQExpBuffer target;
-	Oid			pgClassOid;
 	int			i;
 	int			ntups;
 	int			i_attname;
 	int			i_attnum;
+	int			i_attisdropped;
 
 	/* do nothing, if --no-comments is supplied */
 	if (fout->dopt->no_comments)
 		return;
 
-	query = createPQExpBuffer();
-
-	appendPQExpBuffer(query,
-					  "SELECT c.tableoid, a.attname, a.attnum "
-					  "FROM pg_catalog.pg_class c, pg_catalog.pg_attribute a "
-					  "WHERE c.oid = '%u' AND c.oid = a.attrelid "
-					  "  AND NOT a.attisdropped "
-					  "ORDER BY a.attnum ",
-					  tyinfo->typrelid);
-
-	/* Fetch column attnames */
-	res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
-
-	ntups = PQntuples(res);
-	if (ntups < 1)
-	{
-		PQclear(res);
-		destroyPQExpBuffer(query);
-		return;
-	}
-
-	pgClassOid = atooid(PQgetvalue(res, 0, PQfnumber(res, "tableoid")));
-
 	/* Search for comments associated with type's pg_class OID */
-	ncomments = findComments(fout,
-							 pgClassOid,
-							 tyinfo->typrelid,
+	ncomments = findComments(RelationRelationId, tyinfo->typrelid,
 							 &comments);
 
 	/* If no comments exist, we're done */
 	if (ncomments <= 0)
-	{
-		PQclear(res);
-		destroyPQExpBuffer(query);
 		return;
-	}
 
 	/* Build COMMENT ON statements */
+	query = createPQExpBuffer();
 	target = createPQExpBuffer();
 
+	ntups = PQntuples(res);
 	i_attnum = PQfnumber(res, "attnum");
 	i_attname = PQfnumber(res, "attname");
+	i_attisdropped = PQfnumber(res, "attisdropped");
 	while (ncomments > 0)
 	{
 		const char *attname;
 
 		attname = NULL;
 		for (i = 0; i < ntups; i++)
 		{
-			if (atoi(PQgetvalue(res, i, i_attnum)) == comments->objsubid)
+			if (atoi(PQgetvalue(res, i, i_attnum)) == comments->objsubid &&
+				PQgetvalue(res, i, i_attisdropped)[0] != 't')
 			{
 				attname = PQgetvalue(res, i, i_attname);
 				break;
@@ -11013,7 +10989,6 @@ dumpCompositeTypeColComments(Archive *fout, const TypeInfo *tyinfo)
 		ncomments--;
 	}
 
-	PQclear(res);
 	destroyPQExpBuffer(query);
 	destroyPQExpBuffer(target);
 }
@@ -14254,7 +14229,7 @@ dumpSecLabel(Archive *fout, const char *type, const char *name,
 	}
 
 	/* Search for security labels associated with catalogId, using table */
-	nlabels = findSecLabels(fout, catalogId.tableoid, catalogId.oid, &labels);
+	nlabels = findSecLabels(catalogId.tableoid, catalogId.oid, &labels);
 
 	query = createPQExpBuffer();
 
@@ -14321,8 +14296,7 @@ dumpTableSecLabel(Archive *fout, const TableInfo *tbinfo, const char *reltypenam
 		return;
 
 	/* Search for comments associated with relation, using table */
-	nlabels = findSecLabels(fout,
-							tbinfo->dobj.catId.tableoid,
+	nlabels = findSecLabels(tbinfo->dobj.catId.tableoid,
 							tbinfo->dobj.catId.oid,
 							&labels);
 
@@ -14386,7 +14360,7 @@ dumpTableSecLabel(Archive *fout, const TableInfo *tbinfo, const char *reltypenam
  * found with one search.
  */
 static int
-findSecLabels(Archive *fout, Oid classoid, Oid objoid, SecLabelItem **items)
+findSecLabels(Oid classoid, Oid objoid, SecLabelItem **items)
 {
 	SecLabelItem *middle = NULL;
 	SecLabelItem *low;