The MySQL Enterprise Audit Plugin helps audit and monitor all activities within MySQL, tracking queries, logins, and user actions for enhanced security. The other options help with performance but are not security-focused.

A MySQL account with an empty password allows anyone to connect without authentication, leading to unauthorized database access. The other options are unrelated to password security.

sync_binlog=1 ensures that every transaction is written to disk immediately, preventing log corruption. binlog_checksum detects errors. Disabling binary logging removes recovery options, and MEMORY storage does not persist logs.

Table Compression in MySQL reduces disk storage usage by storing data in a more compact format, making it ideal for large databases. Other techniques focus on performance rather than storage.

The binlog_encryption=ON system variable enables binary log encryption in MySQL 8.0. This ensures that binary logs, relay logs, and other log files are encrypted before being written to disk. The other options are not valid MySQL system variables for enabling binary log encryption.

The Execution Plan Drift Alert notifies users when MySQL‘s query optimizer changes execution plans, which can cause unexpected performance regressions. Index usage and buffer pool metrics do not directly detect this issue.

The Query Analyzer in MySQL Enterprise Monitor provides a detailed breakdown of query execution times, helping detect long-running and inefficient queries. The Performance Schema and Slow Query Log offer insights but are not part of Enterprise Monitor’s query analysis tools.

The innodb_max_dirty_pages_pct variable sets the threshold for dirty pages in the buffer pool before flushing them to disk. Flush log settings control log writes, buffer pool instances affect concurrency, and adaptive flushing adjusts page cleaning behavior.

InnoDB Full Page Writes prevent corruption by storing a full-page image before making changes, ensuring crash recovery can reconstruct pages correctly. This prevents half-written pages from causing data inconsistencies. The other options focus on log management and flushing strategies.

Asynchronous replication relies on binary logs to record changes, which replicas retrieve to maintain data consistency. Without binary logging, replication cannot function properly.

The Binary Log records all INSERT, UPDATE, and DELETE operations, helping administrators identify excessive data growth patterns. The Slow Query Log and General Query Log do not track data growth, and the Error Log only records failures.

The optimizer_switch variable allows fine-tuning of query optimizer behavior by enabling or disabling various optimization techniques. optimizer_prune_level affects subquery optimization, optimizer_max_join_size limits large join execution, and optimizer_search_depth controls how deep the optimizer evaluates query plans.

The TRANSACTIONS section of SHOW ENGINE INNODB STATUS provides detailed transaction information, including active transactions, pending commits, and locks held. Other sections focus on memory, I/O, or lock details.

MySQL’s optimizer uses statistics about table size, index cardinality, and query conditions to choose between index scans or table scans. It does not automatically choose table scans for smaller tables or prioritize index order.

The REVOKE statement is used to remove specific privileges without affecting other permissions. REMOVE and DROP PRIVILEGE are invalid commands, and DELETE FROM mysql.db is not recommended as it bypasses privilege management.

Semi-synchronous replication ensures zero data loss by waiting for at least one replica to confirm receiving binary log changes before committing. This guarantees durability in case of primary server failure. Asynchronous replication lacks this guarantee. Delayed replication is useful for recovery but does not prevent loss. Statement-based replication can lead to inconsistency due to non-deterministic execution.

Binary logs allow point-in-time recovery after accidental deletions, replaying transactions up to a specific moment. Database crashes may require redo logs instead. Query optimization and migrations do not need binary log backups.

The ALTER USER privilege allows a user to change their own password. UPDATE ON mysql.user is not allowed for security reasons, CHANGE PASSWORD is not a valid privilege, and MODIFY ACCOUNT does not exist in MySQL.

The max_connections option controls the maximum number of simultaneous client connections. It does not set memory limits, query limits, or thread spawning behavior.

MySQL Enterprise Firewall provides security by monitoring, learning, and blocking unauthorized SQL queries, preventing injection attacks. It does not handle TLS encryption, password hashing, or auditing directly. These tasks are managed by separate MySQL security features.

The Seconds_Behind_Source value represents the difference between the current primary transaction timestamp and the replica’s last applied transaction timestamp. It does not predict synchronization time, track last commit duration, or measure event execution delays.

The –disable-foreign-keys option in mysqldump ensures that foreign key checks are disabled during restoration. –disable-checks-table does not exist. –ignore-key-constraints is invalid, and –skip-index-validations is unrelated.

The yum install mysql-server command is used to download and install MySQL on RHEL-based systems. The other commands either contain incorrect syntax or refer to non-RHEL package managers.

The Information Schema provides a view-based interface for accessing Data Dictionary metadata. The other options reference non-existent tables or incorrect sources.

The audit_log_format system variable defines whether audit logs are stored in JSON or XML format. Other options do not exist in MySQL 8.0.

The validate_password_length variable defines the minimum and maximum password length for MySQL user accounts. The other options do not exist as valid MySQL settings.

The SHOW PROCESSLIST command provides real-time insight into active connections, running queries, and thread statuses. Other commands focus on status variables, storage engine internals, or configuration settings.

InnoDB Change Buffering optimizes performance by delaying secondary index updates and merging changes later. Redo Log Batching and Write-Ahead Logging improve transaction durability, but do not buffer index changes.

Before bootstrapping an InnoDB Cluster, you must enable Group Replication and set up instance credentials. MySQL Router setup, backup snapshots, or binary log synchronization are not prerequisites for initializing the cluster.

The CURRENT_ROLE() function returns the active roles assigned to the current session. SHOW GRANTS lists privileges but does not filter by active roles. SHOW ROLES and SESSION_ROLE() do not exist in MySQL.

To enable MySQL Enterprise Audit, the INSTALL PLUGIN command is used with the appropriate shared library file. Other options do not exist or are not valid for enabling the audit plugin.

Replication lag occurs when a transaction is committed on the primary server but is not yet applied to the replica server. This delay can be caused by network latency, slow disk writes, or heavy load on the replica. It is an important factor in replication performance, as excessive lag can cause outdated data on replicas. The delay in query execution (latency), difference in processed queries, and memory flushing to disk are separate concepts and do not define replication lag.

The mysqladmin –show-server-status command displays the current status of the MySQL server. The other options reference non-existent or incorrect commands.

Setting slow_query_log=ON dynamically enables the slow query log without a server restart. The other options either do not exist or require indirect modifications to system files.

The –default-parallelism option in mysqlpump enables parallel execution of table dumps, speeding up large database backups. –optimized-storage-set does not exist. –index-priority-cache is unrelated, and –transactional-logging refers to binary logs, not backups.

The tmpdir variable specifies the temporary file directory for MySQL, which must be unique for each instance to avoid file access conflicts. join_buffer_size and innodb_buffer_pool_size affect performance but do not create file conflicts. table_definition_cache controls metadata caching but does not impact multiple instance execution.

The data modification rate influences how frequently backups are required to minimize data loss risk. Query execution speed affects performance but does not dictate backup schedules. User connection count impacts server load, and index optimization level relates to query speed, not backups.

The SUM(data_length + index_length) query in Information Schema calculates the total storage used by tables and indexes in a database. The other options are invalid or do not provide a direct measurement of database size.

MySQL InnoDB Cluster combines Group Replication with MySQL Router, enabling automatic failover by detecting node failures and promoting a new primary with minimal downtime.

Savepoints allow a transaction to be rolled back to a specific state instead of fully rolling back. This feature is useful for managing complex transactions where partial rollback is required. Point-in-time recovery uses binary logs but does not allow selective transaction rollback. Replication copies changes across servers but is not related to rollback.

The DROP privilege should be restricted to prevent SQL injection attacks from dropping critical tables. Limiting access to the DROP privilege reduces the potential damage. The other options are more common and needed for regular database use.

Before restarting an InnoDB Cluster, it is critical to verify the replication state across all nodes to prevent data inconsistency. Modifying MySQL Router, enabling semi-sync replication, or adjusting binlog retention is not necessary for recovery.

The InnoDB redo log records changes to pages in the buffer pool before they are written to disk. This ensures durability and allows crash recovery by replaying changes that were not flushed to the tablespace before a failure. The redo log is essential for maintaining data integrity in case of unexpected shutdowns. The binary logs, on the other hand, track changes for replication and point-in-time recovery, but they are not the same as the redo log. Audit logs, which store executed queries, serve a different purpose.

The Innodb_row_lock_waits metric shows the number of times transactions had to wait for row locks, helping diagnose lock contention issues. Other metrics track memory usage, deadlocks, and log buffer delays, but not row locks.

The max_binlog_size variable sets the maximum size of a binary log file before MySQL automatically rotates it. The other options do not exist in MySQL.

The cost_estimate field in optimizer_trace explains why MySQL chose a specific index, based on cost calculations. query_block_id identifies query parts but does not explain index choice. partition_used refers to partitioning, not indexing. ref_or_null relates to JOIN optimizations.

The max_allowed_packet variable defines the largest single packet or network message that MySQL will accept from a client. If a packet exceeds this size, MySQL rejects the query with an error. The other variables manage log file sizes, network buffers, and temporary table limits but do not control packet size.

The MySQL System Schema contains Data Dictionary metadata tables, replacing legacy storage methods. The Information Schema provides metadata views, and the Performance Schema is used for performance monitoring.

The CREATE USER privilege allows a user to create, modify, and remove user accounts in MySQL. CREATE applies only to database objects, USER_ADMIN is not a valid privilege, and ACCOUNT_ADMIN does not exist in MySQL 8.0.

The Repeatable Read isolation level is the default in MySQL 8.0 and ensures that once a transaction reads data, subsequent reads within the same transaction will see the same data, even if other transactions modify it. This prevents dirty reads (reading uncommitted data) and minimizes non-repeatable reads. While Read Committed prevents dirty reads, it does not guarantee repeatable reads. Serializable is the strictest level, ensuring full isolation but reducing concurrency.

The require_secure_transport=ON setting ensures that all client connections must use SSL/TLS encryption, preventing unencrypted data transmission. The other options are invalid or nonexistent MySQL settings.

The /var/lib/mysql/data-store directory contains all MySQL data files needed for raw file backups. Configuration files are in /etc/mysql/. Binaries and tools are stored in /usr/local/bin/. Plugins and caches are separate from data storage.

The default authentication plugin in MySQL 8.0 is caching_sha2_password, which provides stronger security than older methods. Using mysql_native_password is supported but not recommended. The sha256_password plugin exists but is not the default. If no authentication plugin is specified, MySQL uses caching_sha2_password by default.

The Coordinator thread manages parallel replication by distributing transactions to multiple worker threads, improving replication speed. It does not synchronize logs, adjust network buffers, or prevent duplicate transactions (GTIDs handle that).

To activate a role for the current session, the correct command is SET ROLE ‘role_name‘. Other options (USE ROLE, ENABLE ROLE, ACTIVATE ROLE) do not exist in MySQL 8.0. Roles must be explicitly set per session unless assigned as a default role.

Multisource replication is enabled by defining separate replication channels, each receiving transactions from one primary server. Parallel execution, logical clocks, and binlog caching are beneficial but do not provide multisource replication support directly.

The InnoDB Storage Engine supports ACID compliance and includes crash recovery capabilities. It maintains a redo log and undo log, which ensure that transactions are either fully committed or completely rolled back in the event of a crash. Unlike MyISAM, which does not support crash recovery, InnoDB automatically restores its state using its transaction logs, making it the preferred storage engine for critical applications.

The CREATE AUDIT FILTER command defines filtering rules for auditing specific users or operations. The other options are either invalid syntax or do not exist in MySQL 8.0.

The –compress backup mode in MySQL Enterprise Backup reduces backup file size by applying compression. –backup directory path specifies where the backup is stored. –apply-log recovery step applies incremental backups, and –incremental restore is used for restoring only changed data.

Row-Based Locking minimizes table-wide contention by allowing transactions to lock individual rows instead of entire tables. Query Caching does not affect locks, Write-Ahead Logging improves durability, and Heap Storage is limited to memory tables.