use pg_ptrack_get_block_2 to read block by relfilenode without relcache

Author: alubennikova

src/backup.c

@@ -2677,55 +2677,59 @@ pg_ptrack_get_block(Oid dbOid,
 	PGresult   *res_db;
 	PGresult   *res;
 	const char *dbname;
-	char	   *params[3];
+	char	   *params[4];
 	char	   *result;
 	char	   *val;
 	PGconn	   *tmp_conn;
 
 	params[0] = palloc(64);
 	params[1] = palloc(64);
 	params[2] = palloc(64);
-
-	sprintf(params[0], "%i", dbOid);
-	res_db = pgut_execute(backup_conn,
-							"SELECT datname FROM pg_database WHERE oid=$1",
-							1, (const char **) params, true);
-	/*
-	 * If database is not found, it's not an error.
-	 * It could have been deleted.
-	 */
-	if (PQntuples(res_db) != 1 || PQnfields(res_db) != 1)
-	{
-		//elog(LOG, "Database with oid %d is not found", dbOid);
-		return NULL;
-	}
-
-	dbname = PQgetvalue(res_db, 0, 0);
-	if (strcmp(dbname, "template0") == 0)
-	{
-		/*
-		 * There is no way to connect to the template0 database.
-		 * But it's totally OK, since files there can never be changed.
-		 */
-		return NULL;
-	}
-	tmp_conn = pgut_connect(dbname);
+	params[3] = palloc(64);
+
+// 	sprintf(params[0], "%i", dbOid);
+// 	res_db = pgut_execute(backup_conn,
+// 							"SELECT datname FROM pg_database WHERE oid=$1",
+// 							1, (const char **) params, true);
+// 	/*
+// 	 * If database is not found, it's not an error.
+// 	 * It could have been deleted.
+// 	 */
+// 	if (PQntuples(res_db) != 1 || PQnfields(res_db) != 1)
+// 	{
+// 		//elog(LOG, "Database with oid %d is not found", dbOid);
+// 		return NULL;
+// 	}
+// 
+// 	dbname = PQgetvalue(res_db, 0, 0);
+// 	if (strcmp(dbname, "template0") == 0)
+// 	{
+// 		/*
+// 		 * There is no way to connect to the template0 database.
+// 		 * But it's totally OK, since files there can never be changed.
+// 		 */
+// 		return NULL;
+// 	}
+// 	tmp_conn = pgut_connect(dbname);
 
 	/*
 	 * Use backup_conn, cause we can do it from any database.
 	 */
 	sprintf(params[0], "%i", tblsOid);
-	sprintf(params[1], "%i", relOid);
-	sprintf(params[2], "%u", blknum);
+	sprintf(params[1], "%i", dbOid);
+	sprintf(params[2], "%i", relOid);
+	sprintf(params[3], "%u", blknum);
 
-	//elog(WARNING, "db %i pg_ptrack_get_block(%i, %i, %u)",dbOid, tblsOid, relOid, blknum);
-
-	res = pgut_execute(tmp_conn, "SELECT pg_ptrack_get_block($1, $2, $3)",
-					3, (const char **)params, true);
+	//elog(LOG, "db %i pg_ptrack_get_block(%i, %i, %u)",dbOid, tblsOid, relOid, blknum);
+	res = pgut_execute(backup_conn, "SELECT pg_ptrack_get_block_2($1, $2, $3, $4)",
+					4, (const char **)params, true);
 
 	if (PQnfields(res) != 1)
-		elog(WARNING, "cannot get file block for relation oid %u",
-		relOid);
+	{
+		elog(LOG, "cannot get file block for relation oid %u",
+					   relOid);
+		return NULL;
+	}
 
 	val = PQgetvalue(res, 0, 0);
 
@@ -2735,12 +2739,14 @@ pg_ptrack_get_block(Oid dbOid,
 	result = (char *) PQunescapeBytea((unsigned char *) PQgetvalue(res, 0, 0),
 									  result_size);
 
-	pgut_disconnect(tmp_conn);
+// 	pgut_disconnect(tmp_conn);
+// 	PQclear(res_db);
+
 	PQclear(res);
-	PQclear(res_db);
 	pfree(params[0]);
 	pfree(params[1]);
 	pfree(params[2]);
+	pfree(params[3]);
 
 	return result;
 }