Cleanup: Remove changed_pages_bitmap

The innodb_changed_pages plugin only was part of XtraDB, never InnoDB.
It would be useful for incremental backups.
We will remove the code from mariadb-backup for now, because it cannot
serve any useful purpose until the server part has been implemented.

extra/mariabackup/CMakeLists.txt

@@ -57,7 +57,6 @@ ADD_DEFINITIONS(${SSL_DEFINES})
 MYSQL_ADD_EXECUTABLE(mariadb-backup
   xtrabackup.cc
   innobackupex.cc
-  changed_page_bitmap.cc
   datasink.cc
   ds_buffer.cc
   ds_compress.cc

extra/mariabackup/backup_mysql.cc

@@ -73,7 +73,6 @@ mysql_flavor_t server_flavor = FLAVOR_UNKNOWN;
 unsigned long mysql_server_version = 0;
 
 /* server capabilities */
-bool have_changed_page_bitmaps = false;
 bool have_backup_locks = false;
 bool have_lock_wait_timeout = false;
 bool have_galera_enabled = false;
@@ -606,34 +605,6 @@ Query the server to find out what backup capabilities it supports.
 bool
 detect_mysql_capabilities_for_backup()
 {
-	const char *query = "SELECT 'INNODB_CHANGED_PAGES', COUNT(*) FROM "
-				"INFORMATION_SCHEMA.PLUGINS "
-			    "WHERE PLUGIN_NAME LIKE 'INNODB_CHANGED_PAGES'";
-	char *innodb_changed_pages = NULL;
-	mysql_variable vars[] = {
-		{"INNODB_CHANGED_PAGES", &innodb_changed_pages}, {NULL, NULL}};
-
-	if (xtrabackup_incremental) {
-
-		read_mysql_variables(mysql_connection, query, vars, true);
-
-		ut_ad(innodb_changed_pages != NULL);
-
-		have_changed_page_bitmaps = (atoi(innodb_changed_pages) == 1);
-
-		/* INNODB_CHANGED_PAGES are listed in
-		INFORMATION_SCHEMA.PLUGINS in MariaDB, but
-		FLUSH NO_WRITE_TO_BINLOG CHANGED_PAGE_BITMAPS
-		is not supported for versions below 10.1.6
-		(see MDEV-7472) */
-		if (server_flavor == FLAVOR_MARIADB &&
-		    mysql_server_version < 100106) {
-			have_changed_page_bitmaps = false;
-		}
-
-		free_mysql_variables(vars);
-	}
-
 	/* do some sanity checks */
 	if (opt_galera_info && !have_galera_enabled) {
 		msg("--galera-info is specified on the command "
@@ -1997,18 +1968,6 @@ select_history()
 	return(true);
 }
 
-bool
-flush_changed_page_bitmaps()
-{
-	if (xtrabackup_incremental && have_changed_page_bitmaps &&
-	    !xtrabackup_incremental_force_scan) {
-		xb_mysql_query(mysql_connection,
-			"FLUSH NO_WRITE_TO_BINLOG CHANGED_PAGE_BITMAPS", false);
-	}
-	return(true);
-}
-
-
 /*********************************************************************//**
 Deallocate memory, disconnect from server, etc.
 @return	true on success. */

extra/mariabackup/backup_mysql.h

@@ -10,7 +10,6 @@ extern mysql_flavor_t server_flavor;
 extern unsigned long mysql_server_version;
 
 /* server capabilities */
-extern bool have_changed_page_bitmaps;
 extern bool have_backup_locks;
 extern bool have_lock_wait_timeout;
 extern bool have_galera_enabled;
@@ -39,9 +38,6 @@ capture_tool_command(int argc, char **argv);
 bool
 select_history();
 
-bool
-flush_changed_page_bitmaps();
-
 void
 backup_cleanup();