MDEV-7472: Implementation of user statements for handling the xtradb changed page bitmaps

Introduce a new dummy INFORMATION_SCHEMA.CHANGED_PAGE_BITMAPS table to XtraDB
with reset_table callback to allow FLUSH NO_WRITE_TO_BINLOG CHANGED_PAGE_BITMAPS
to be called from innobackupex.

mysql-test/r/mysqld--help.result

@@ -96,6 +96,9 @@ The following options may be given as the first argument:
  --bulk-insert-buffer-size=# 
  Size of tree cache used in bulk insert optimisation. Note
  that this is a limit per thread!
+ --changed-page-bitmaps[=name] 
+ Enable or disable CHANGED_PAGE_BITMAPS plugin. One of:
+ ON, OFF, FORCE (don't start if the plugin fails to load).
  --character-set-client-handshake 
  Don't ignore client side character set value sent during
  handshake.
@@ -1126,6 +1129,7 @@ binlog-optimize-thread-scheduling TRUE
 binlog-row-event-max-size 1024
 binlog-stmt-cache-size 32768
 bulk-insert-buffer-size 8388608
+changed-page-bitmaps ON
 character-set-client-handshake TRUE
 character-set-filesystem binary
 character-set-server latin1

mysql-test/suite/innodb/r/innodb-flush-changed-page-bitmaps.result

+FLUSH NO_WRITE_TO_BINLOG changed_page_bitmaps;
+select * from information_schema.changed_page_bitmaps;
+dummy
+0

mysql-test/suite/innodb/t/innodb-flush-changed-page-bitmaps.opt

+--changed-page-bitmaps
+--innodb-track-changed-pages

mysql-test/suite/innodb/t/innodb-flush-changed-page-bitmaps.test

+-- source include/have_xtradb.inc
+-- source include/not_embedded.inc
+
+FLUSH NO_WRITE_TO_BINLOG changed_page_bitmaps;
+select * from information_schema.changed_page_bitmaps;

storage/xtradb/handler/ha_innodb.cc

@@ -4240,7 +4240,6 @@ innobase_flush_logs(
 Synchronously read and parse the redo log up to the last
 checkpoint to write the changed page bitmap.
 @return 0 to indicate success.  Current implementation cannot fail. */
-static
 my_bool
 innobase_flush_changed_page_bitmaps()
 /*=================================*/
@@ -20791,7 +20790,8 @@ i_s_innodb_changed_pages,
 i_s_innodb_mutexes,
 i_s_innodb_sys_semaphore_waits,
 i_s_innodb_tablespaces_encryption,
-i_s_innodb_tablespaces_scrubbing
+i_s_innodb_tablespaces_scrubbing,
+i_s_innodb_changed_page_bitmaps
 maria_declare_plugin_end;
 
 /** @brief Initialize the default value of innodb_commit_concurrency.

storage/xtradb/handler/i_s.cc

@@ -9459,3 +9459,128 @@ UNIV_INTERN struct st_mysql_plugin	i_s_innodb_sys_semaphore_waits =
 	STRUCT_FLD(version_info, INNODB_VERSION_STR),
         STRUCT_FLD(maturity, MariaDB_PLUGIN_MATURITY_BETA),
 };
+
+static ST_FIELD_INFO	innodb_changed_page_bitmaps_fields_info[] =
+{
+	{STRUCT_FLD(field_name,		"dummy"),
+	 STRUCT_FLD(field_length,	MY_INT64_NUM_DECIMAL_DIGITS),
+	 STRUCT_FLD(field_type,		MYSQL_TYPE_LONGLONG),
+	 STRUCT_FLD(value,		0),
+	 STRUCT_FLD(field_flags,	MY_I_S_UNSIGNED),
+	 STRUCT_FLD(old_name,		""),
+	 STRUCT_FLD(open_method,	SKIP_OPEN_TABLE)},
+	END_OF_ST_FIELD_INFO
+};
+
+/*******************************************************************//**
+Function to populate INFORMATION_SCHEMA.CHANGED_PAGE_BITMAPS
+@return 0 on success */
+static
+int
+fill_changed_page_bitmaps_table(
+/*============================*/
+	THD*		thd,	/*!< in: thread */
+	TABLE_LIST*	tables,	/*!< in/out: tables to fill */
+	Item*		)	/*!< in: condition (not used) */
+{
+	Field**		fields = tables->table->field;
+	DBUG_ENTER("fill_changed_page_bitmaps");
+	RETURN_IF_INNODB_NOT_STARTED(tables->schema_table_name);
+
+	/* deny access to user without PROCESS_ACL privilege */
+	if (check_global_access(thd, PROCESS_ACL)) {
+		DBUG_RETURN(0);
+	}
+	OK(field_store_ulint(fields[0], 0));
+	OK(schema_table_store_record(thd, tables->table));
+
+	DBUG_RETURN(0);
+}
+
+/*******************************************************************//**
+Flush support for changed_page_bitmaps table.
+@return 0 on success */
+static
+int
+flush_changed_page_bitmaps()
+/*========================*/
+{
+	DBUG_ENTER("flush_changed_page_bitmaps");
+	if (srv_track_changed_pages) {
+		os_event_reset(srv_checkpoint_completed_event);
+		log_online_follow_redo_log();
+	}
+	DBUG_RETURN(0);
+}
+
+/*******************************************************************//**
+Bind the dynamic table INFORMATION_SCHEMA.CHANGED_PAGE_BITMAP
+@return 0 on success */
+static
+int
+innodb_changed_page_bitmaps_init(
+/*=============================*/
+	void*	p)	/*!< in/out: table schema object */
+{
+	ST_SCHEMA_TABLE*	schema;
+
+	DBUG_ENTER("innodb_changed_page_bitmaps_init");
+
+	schema = (ST_SCHEMA_TABLE*) p;
+
+	schema->fields_info = innodb_changed_page_bitmaps_fields_info;
+	schema->fill_table = fill_changed_page_bitmaps_table;
+	schema->reset_table= flush_changed_page_bitmaps;
+
+	DBUG_RETURN(0);
+}
+
+UNIV_INTERN struct st_mysql_plugin	i_s_innodb_changed_page_bitmaps =
+{
+	/* the plugin type (a MYSQL_XXX_PLUGIN value) */
+	/* int */
+	STRUCT_FLD(type, MYSQL_INFORMATION_SCHEMA_PLUGIN),
+
+	/* pointer to type-specific plugin descriptor */
+	/* void* */
+	STRUCT_FLD(info, &i_s_info),
+
+	/* plugin name */
+	/* const char* */
+	STRUCT_FLD(name, "CHANGED_PAGE_BITMAPS"),
+
+	/* plugin author (for SHOW PLUGINS) */
+	/* const char* */
+	STRUCT_FLD(author, maria_plugin_author),
+
+	/* general descriptive text (for SHOW PLUGINS) */
+	/* const char* */
+	STRUCT_FLD(descr, "XtraDB dummy changed_page_bitmaps table"),
+
+	/* the plugin license (PLUGIN_LICENSE_XXX) */
+	/* int */
+	STRUCT_FLD(license, PLUGIN_LICENSE_GPL),
+
+	/* the function to invoke when plugin is loaded */
+	/* int (*)(void*); */
+	STRUCT_FLD(init, innodb_changed_page_bitmaps_init),
+
+	/* the function to invoke when plugin is unloaded */
+	/* int (*)(void*); */
+	STRUCT_FLD(deinit, i_s_common_deinit),
+
+	/* plugin version (for SHOW PLUGINS) */
+	/* unsigned int */
+	STRUCT_FLD(version, INNODB_VERSION_SHORT),
+
+	/* struct st_mysql_show_var* */
+	STRUCT_FLD(status_vars, NULL),
+
+	/* struct st_mysql_sys_var** */
+	STRUCT_FLD(system_vars, NULL),
+
+        /* Maria extension */
+	STRUCT_FLD(version_info, INNODB_VERSION_STR),
+        STRUCT_FLD(maturity, MariaDB_PLUGIN_MATURITY_BETA),
+};
+

storage/xtradb/handler/i_s.h

@@ -67,6 +67,7 @@ extern struct st_mysql_plugin	i_s_innodb_mutexes;
 extern struct st_maria_plugin	i_s_innodb_tablespaces_encryption;
 extern struct st_maria_plugin	i_s_innodb_tablespaces_scrubbing;
 extern struct st_mysql_plugin	i_s_innodb_sys_semaphore_waits;
+extern struct st_mysql_plugin	i_s_innodb_changed_page_bitmaps;
 
 /** maximum number of buffer page info we would cache. */
 #define MAX_BUF_INFO_CACHED		10000