From e5275dce0cb482ee8fed52a9c797f5182b40a942 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Mon, 8 Jul 2024 21:42:22 -0500
Subject: [PATCH v7 10/11] parallelize tables with oids check in pg_upgrade

---
 src/bin/pg_upgrade/check.c | 90 ++++++++++++++++++++------------------
 1 file changed, 48 insertions(+), 42 deletions(-)

diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index 32c29aa881..410d8b0cad 100644
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -1520,15 +1520,58 @@ check_for_incompatible_polymorphics(ClusterInfo *cluster)
 	termPQExpBuffer(&state.old_polymorphics);
 }
 
+static char *
+with_oids_query(void *arg)
+{
+	return pg_strdup("SELECT n.nspname, c.relname "
+					 "FROM   pg_catalog.pg_class c, "
+					 "       pg_catalog.pg_namespace n "
+					 "WHERE  c.relnamespace = n.oid AND "
+					 "       c.relhasoids AND"
+					 "       n.nspname NOT IN ('pg_catalog')");
+}
+
+static void
+with_oids_process(DbInfo *dbinfo, PGresult *res, void *arg)
+{
+	bool		db_used = false;
+	int			ntups = PQntuples(res);
+	char		output_path[MAXPGPATH];
+	int			i_nspname = PQfnumber(res, "nspname");
+	int			i_relname = PQfnumber(res, "relname");
+	FILE	  **script = (FILE **) arg;
+
+	if (!ntups)
+		return;
+
+	snprintf(output_path, sizeof(output_path), "%s/%s",
+			 log_opts.basedir,
+			 "tables_with_oids.txt");
+
+	for (int rowno = 0; rowno < ntups; rowno++)
+	{
+		if (*script == NULL && (*script = fopen_priv(output_path, "w")) == NULL)
+			pg_fatal("could not open file \"%s\": %m", output_path);
+		if (!db_used)
+		{
+			fprintf(*script, "In database: %s\n", dbinfo->db_name);
+			db_used = true;
+		}
+		fprintf(*script, "  %s.%s\n",
+				PQgetvalue(res, rowno, i_nspname),
+				PQgetvalue(res, rowno, i_relname));
+	}
+}
+
 /*
  * Verify that no tables are declared WITH OIDS.
  */
 static void
 check_for_tables_with_oids(ClusterInfo *cluster)
 {
-	int			dbnum;
 	FILE	   *script = NULL;
 	char		output_path[MAXPGPATH];
+	AsyncTask  *task = async_task_create();
 
 	prep_status("Checking for tables WITH OIDS");
 
@@ -1536,47 +1579,10 @@ check_for_tables_with_oids(ClusterInfo *cluster)
 			 log_opts.basedir,
 			 "tables_with_oids.txt");
 
-	/* Find any tables declared WITH OIDS */
-	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
-	{
-		PGresult   *res;
-		bool		db_used = false;
-		int			ntups;
-		int			rowno;
-		int			i_nspname,
-					i_relname;
-		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
-		PGconn	   *conn = connectToServer(cluster, active_db->db_name);
-
-		res = executeQueryOrDie(conn,
-								"SELECT n.nspname, c.relname "
-								"FROM	pg_catalog.pg_class c, "
-								"		pg_catalog.pg_namespace n "
-								"WHERE	c.relnamespace = n.oid AND "
-								"		c.relhasoids AND"
-								"       n.nspname NOT IN ('pg_catalog')");
-
-		ntups = PQntuples(res);
-		i_nspname = PQfnumber(res, "nspname");
-		i_relname = PQfnumber(res, "relname");
-		for (rowno = 0; rowno < ntups; rowno++)
-		{
-			if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-				pg_fatal("could not open file \"%s\": %m", output_path);
-			if (!db_used)
-			{
-				fprintf(script, "In database: %s\n", active_db->db_name);
-				db_used = true;
-			}
-			fprintf(script, "  %s.%s\n",
-					PQgetvalue(res, rowno, i_nspname),
-					PQgetvalue(res, rowno, i_relname));
-		}
-
-		PQclear(res);
-
-		PQfinish(conn);
-	}
+	async_task_add_step(task, with_oids_query,
+						with_oids_process, true, &script);
+	async_task_run(task, cluster);
+	async_task_free(task);
 
 	if (script)
 	{
-- 
2.39.3 (Apple Git-146)