MDEV-27848: Remove unused wait/io/file/innodb/innodb_log_file

The performance_schema counter wait/io/file/innodb/innodb_log_file
is always reported as 0.

The way how redo log writes are being waited for was refactored in
commit 30ea63b7d2 by the introduction
of flush_lock and write_lock. Even before that change, all the
wait/io/file/innodb/ counters were always 0 in my tests.

Moreover, if the PMEM interface that was introduced in
commit 3daef523af
is being used, writes to the InnoDB log file will completely avoid
any system calls and performance_schema instrumentation.
In commit 685d958e38 also the reads
of the redo log (during recovery) would bypass any system calls.

extra/mariabackup/xtrabackup.cc

@@ -2274,10 +2274,10 @@ static bool innodb_init()
 
   bool ret;
   const std::string ib_logfile0{get_log_file_path()};
-  os_file_delete_if_exists(innodb_log_file_key, ib_logfile0.c_str(), nullptr);
-  pfs_os_file_t file= os_file_create(innodb_log_file_key, ib_logfile0.c_str(),
-                                     OS_FILE_CREATE, OS_FILE_NORMAL,
-                                     OS_DATA_FILE_NO_O_DIRECT, false, &ret);
+  os_file_delete_if_exists_func(ib_logfile0.c_str(), nullptr);
+  os_file_t file= os_file_create_func(ib_logfile0.c_str(),
+                                      OS_FILE_CREATE, OS_FILE_NORMAL,
+                                      OS_DATA_FILE_NO_O_DIRECT, false, &ret);
   if (!ret)
   {
   invalid_log:
@@ -2298,13 +2298,12 @@ static bool innodb_init()
 
 #ifdef _WIN32
   DWORD len;
-  ret= WriteFile(os_file_t{file}, log_hdr_buf, sizeof log_hdr_buf,
+  ret= WriteFile(file, log_hdr_buf, sizeof log_hdr_buf,
                  &len, nullptr) && len == sizeof log_hdr_buf;
 #else
-  ret= sizeof log_hdr_buf == write(os_file_t{file}, log_hdr_buf,
-                                   sizeof log_hdr_buf);
+  ret= sizeof log_hdr_buf == write(file, log_hdr_buf, sizeof log_hdr_buf);
 #endif
-  if (!os_file_close(file) || !ret)
+  if (!os_file_close_func(file) || !ret)
     goto invalid_log;
   return false;
 }

storage/innobase/handler/ha_innodb.cc

@@ -635,7 +635,6 @@ static PSI_thread_info	all_innodb_threads[] = {
 performance schema instrumented if "UNIV_PFS_IO" is defined */
 static PSI_file_info	all_innodb_files[] = {
 	PSI_KEY(innodb_data_file),
-	PSI_KEY(innodb_log_file),
 	PSI_KEY(innodb_temp_file)
 };
 # endif /* UNIV_PFS_IO */

storage/innobase/include/log0log.h

@@ -55,7 +55,7 @@ std::string get_log_file_path(const char *filename= LOG_FILE_NAME);
 static inline void delete_log_file(const char* suffix)
 {
   auto path = get_log_file_path(LOG_FILE_NAME_PREFIX).append(suffix);
-  os_file_delete_if_exists(innodb_log_file_key, path.c_str(), nullptr);
+  os_file_delete_if_exists_func(path.c_str(), nullptr);
 }
 
 struct completion_callback;
@@ -128,10 +128,10 @@ struct log_t;
 class log_file_t
 {
   friend log_t;
-  pfs_os_file_t m_file;
+  os_file_t m_file{OS_FILE_CLOSED};
 public:
   log_file_t()= default;
-  log_file_t(pfs_os_file_t file) noexcept : m_file(file) {}
+  log_file_t(os_file_t file) noexcept : m_file(file) {}
 
   /** Open a file
   @return file size in bytes

storage/innobase/include/os0file.h

@@ -447,7 +447,6 @@ bool os_file_close_func(os_file_t file);
 
 /* Keys to register InnoDB I/O with performance schema */
 extern mysql_pfs_key_t	innodb_data_file_key;
-extern mysql_pfs_key_t	innodb_log_file_key;
 extern mysql_pfs_key_t	innodb_temp_file_key;
 
 /* Following four macros are instumentations to register

storage/innobase/log/log0recv.cc

@@ -1639,10 +1639,10 @@ dberr_t recv_sys_t::find_checkpoint()
     file_checkpoint= 0;
     std::string path{get_log_file_path()};
     bool success;
-    pfs_os_file_t file= os_file_create(innodb_log_file_key, path.c_str(),
+    os_file_t file{os_file_create_func(path.c_str(),
                                        OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT,
                                        OS_FILE_NORMAL, OS_LOG_FILE,
-                                       srv_read_only_mode, &success);
+                                       srv_read_only_mode, &success)};
     if (file == OS_FILE_CLOSED)
       return DB_ERROR;
     const os_offset_t size{os_file_get_size(file)};
@@ -1665,10 +1665,10 @@ dberr_t recv_sys_t::find_checkpoint()
     for (int i= 1; i < 101; i++)
     {
       path= get_log_file_path(LOG_FILE_NAME_PREFIX).append(std::to_string(i));
-      file= os_file_create(innodb_log_file_key, path.c_str(),
-                           OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT |
-                           OS_FILE_ON_ERROR_SILENT,
-                           OS_FILE_NORMAL, OS_LOG_FILE, true, &success);
+      file= os_file_create_func(path.c_str(),
+                                OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT |
+                                OS_FILE_ON_ERROR_SILENT,
+                                OS_FILE_NORMAL, OS_LOG_FILE, true, &success);
       if (file == OS_FILE_CLOSED)
         break;
       const os_offset_t sz{os_file_get_size(file)};

storage/innobase/os/os0file.cc

@@ -166,7 +166,6 @@ extern uint page_zip_level;
 #ifdef UNIV_PFS_IO
 /* Keys to register InnoDB I/O with performance schema */
 mysql_pfs_key_t  innodb_data_file_key;
-mysql_pfs_key_t  innodb_log_file_key;
 mysql_pfs_key_t  innodb_temp_file_key;
 #endif
 

storage/innobase/srv/srv0start.cc

@@ -200,10 +200,11 @@ static dberr_t create_log_file(bool create_new_db, lsn_t lsn)
 
 	std::string logfile0{get_log_file_path("ib_logfile101")};
 	bool ret;
-	pfs_os_file_t file = os_file_create(
-		innodb_log_file_key, logfile0.c_str(),
-		OS_FILE_CREATE|OS_FILE_ON_ERROR_NO_EXIT, OS_FILE_NORMAL,
-		OS_LOG_FILE, srv_read_only_mode, &ret);
+	os_file_t file{
+          os_file_create_func(logfile0.c_str(),
+                              OS_FILE_CREATE | OS_FILE_ON_ERROR_NO_EXIT,
+                              OS_FILE_NORMAL, OS_LOG_FILE, false, &ret)
+        };
 
 	if (!ret) {
 		sql_print_error("InnoDB: Cannot create %.*s",
@@ -489,7 +490,7 @@ dberr_t
 srv_check_undo_redo_logs_exists()
 {
 	bool		ret;
-	pfs_os_file_t	fh;
+	os_file_t	fh;
 	char	name[OS_FILE_MAX_PATH];
 
 	/* Check if any undo tablespaces exist */
@@ -497,8 +498,8 @@ srv_check_undo_redo_logs_exists()
 
 		snprintf(name, sizeof name, "%s/undo%03zu", srv_undo_dir, i);
 
-		fh = os_file_create(
-			innodb_data_file_key, name,
+		fh = os_file_create_func(
+			name,
 			OS_FILE_OPEN_RETRY
 			| OS_FILE_ON_ERROR_NO_EXIT
 			| OS_FILE_ON_ERROR_SILENT,
@@ -508,7 +509,7 @@ srv_check_undo_redo_logs_exists()
 			&ret);
 
 		if (ret) {
-			os_file_close(fh);
+			os_file_close_func(fh);
 			ib::error()
 				<< "undo tablespace '" << name << "' exists."
 				" Creating system tablespace with existing undo"
@@ -522,14 +523,14 @@ srv_check_undo_redo_logs_exists()
 	/* Check if redo log file exists */
 	auto logfilename = get_log_file_path();
 
-	fh = os_file_create(innodb_log_file_key, logfilename.c_str(),
-			    OS_FILE_OPEN_RETRY | OS_FILE_ON_ERROR_NO_EXIT
-				    | OS_FILE_ON_ERROR_SILENT,
-			    OS_FILE_NORMAL, OS_LOG_FILE, srv_read_only_mode,
-			    &ret);
+	fh = os_file_create_func(logfilename.c_str(),
+				 OS_FILE_OPEN_RETRY | OS_FILE_ON_ERROR_NO_EXIT
+				 | OS_FILE_ON_ERROR_SILENT,
+				 OS_FILE_NORMAL, OS_LOG_FILE,
+				 srv_read_only_mode, &ret);
 
 	if (ret) {
-		os_file_close(fh);
+		os_file_close_func(fh);
 		ib::error() << "redo log file '" << logfilename
 			    << "' exists. Creating system tablespace with"
 			       " existing redo log file is not recommended."