1Z0-908 無料問題集「Oracle MySQL 8.0 Database Administrator」

（A）A manual intervention to force group members to be only the working two instances is required.

（B）The group replication will buffer the transactions on the online nodes until the unreachable nodes return online.

（C）The cluster will shut down to preserve data consistency.

（D）The cluster has built-in high availability and updates group_replication_ip_whitelist to remove the unreachable nodes.

（E）There could be both a 2 node and 3 node group replication still running, so shutting down group replication and diagnosing the issue is recommended.

（A）QN = 1

（B）QN = 3

（C）QN = 4

（D）QN = 5

（E）QN = 2

（A）DISABLED

（B）PREFERRED

（C）VERIFY_CA

（D）REQUIRED

（E）VERIFY_IDENTITY

（A）Snapshot backups can be used only in virtual machines.

（B）There is no need for InnoDB tables to perform its own recovery when restoring from the snapshot backup.

（C）A separate physical copy must be made before releasing the snapshot backup.

（D）Snapshot-based backups greatly reduce time during which the database and applications are unavailable.

（E）The frozen file system can be cloned to another virtual machine immediately into active service.

（A）Execution plans based on transient index statistics improve precision when innodb_stats_persistent_sample_pages is increased.

（B）Setting innodb_stats_auto_recalc=ON causes statistics to be updated automatically when a new index is created.

（C）Increasing innodb_stats_persistent_sample_pages determines higher pages scanning speed, at the cost of increased memory usage.

（D）Updating index statistics is an I/O expensive operation.

（E）Index statistics are calculated from pages buffered in the buffer pool for tables with InnoDB storage engine.

（A）If OPTIMIZE TABLE; is invoked, it will create a table lock on t and force a transaction rollback.

（B）If OPTIMIZE LOCAL TABLE t; is invoked from another session, it executes normally and returns the status.

（C）mysqlcheck --analyze --all-databases will execute normally on all tables and return a report.

（D）If ANALYZE TABLE; is invoked from the same session, it hangs until the transaction is committed or rolled back.

（A）redo tablespaces

（B）data tablespaces

（C）schema tablespaces

（D）undo tablespaces

（E）encryption tablespaces

（F）temporary table tablespaces

（A）It is not mandatory that all instances are running and reachable before running the command.

（B）It picks the minimum number of instances necessary to rebuild the quorum and reconfigures InnoDB Cluster.

（C）It reconfigures InnoDB Cluster if the cluster was stopped.

（D）It only starts all InnoDB Cluster instances.

（E）It performs InnoDB Cluster instances rolling restart.

（F）It only stops and restarts all InnoDB Cluster instances.

（G）It stops and restarts all InnoDB Cluster instances and initializes the metadata.

（A）It is the time between the most recent transaction applied by a SQL thread and the time it was committed on the master.

（B）It is the time between the I/O thread receiving details of the master's last transaction and the time it was written to the relay log on the slave.

（C）It is the time between the most recent transaction written to the relay logs and the time it was committed on the master.

（D）It is the time between the I/O thread receiving details of the master's last transaction and the time it was applied by the SQL thread.

（A）Set binlog_expire_logs_seconds in my.cnf.

（B）Use SET GLOBAL binlog_expire_logs_seconds=<value> and restart the server.

（C）Use PURGE BINARY LOGS to <binlog_name>.

（D）Set binlog_expire_logs_seconds = 0 in my.cnf and restart the server.

（E）Use SET GLOBAL binlog_expire_logs_seconds=<value> and run the FLUSH BINARY LOGS command.

（F）Use SET PERSIST binlog_expire_logs_seconds=<value>.