Before rejoining, the node must have an up-to-date transaction set to prevent inconsistencies. Restarting all nodes, using logical backups, or modifying binlog filtering does not ensure safe rejoining.

Group Replication requires GTIDs for consistent transaction tracking across nodes. It does not require identical hardware, unique binary log identifiers, or a specific isolation level (default REPEATABLE READ is supported).

MySQL Enterprise Backup restores data much faster than mysqldump, as it copies raw physical files rather than executing SQL statements. Easier schema export is irrelevant since it deals with logical exports. Improved logical imports apply to mysqldump, and Enhanced index rebuilds are unrelated.

innodb_stats_auto_recalc determines whether MySQL automatically updates index statistics when table data changes. innodb_auto_optimize is not a valid variable. index_stats_refresh does not exist, and optimizer_index_scan is not a system setting.

The Open Table Cache stores metadata about opened tables, improving performance by reducing filesystem access. The other caches do not handle table metadata.

Whitelisting ensures that only valid inputs are accepted, which prevents malicious data from entering SQL queries. This method helps avoid SQL injection by checking input against safe values before processing.

Forcing a primary instance is required when a quorum is lost, meaning that most nodes are down. Issues like router failures, binary log corruption, or GTID loss do not require forcing a primary.

Binary logs use the .bin extension and store transactional changes. .sql is for mysqldump exports. .log is used for general logs, and .cfg stores MySQL configuration files.

The SHOW REPLICA STATUS command provides detailed information about the replication process on a MySQL slave server. It includes details such as Master_Log_File, Read_Master_Log_Pos, and Seconds_Behind_Master. The SHOW MASTER STATUS command only applies to the master server, while SHOW PROCESSLIST provides session-related details but does not specifically indicate replication status. The SHOW VARIABLES LIKE ‘replication%‘ command only displays general replication settings and does not give real-time replication status.

The SHUTDOWN privilege allows a user to shutdown MySQL securely. The SUPER privilege does grant various administrative tasks, but the SHUTDOWN privilege specifically controls the ability to stop the server.

MySQL Enterprise Backup supports scheduled, automated backups with hot backup capabilities. mysqldump Logical Export requires manual execution unless scripted. mysqlpump Schema Export does not handle automated scheduling, and Binary Log Backup Tool focuses on transaction logs, not automated full backups.

On Windows, MySQL reads configuration settings from C:\ProgramData\MySQL\my-defaults.ini. The other options are invalid or reference incorrect paths.

The mysql_firewall_enable=ON system variable must be set to activate MySQL Enterprise Firewall. The other variables are not valid in MySQL 8.0.

The long_query_time variable specifies the execution time threshold (in seconds) for logging slow queries. The other options do not exist in MySQL 8.0.

In asynchronous replication, the primary does not wait for replicas to confirm writes, which means unreplicated transactions may be lost if the primary crashes before replication is completed.

The –complete-insert-all option ensures that both schema and data are included in the mysqldump output. –routines-triggers-db backs up stored procedures. –create-table-mode does not exist, and –add-drop-database removes existing databases before restoring.

By enabling CA verification (VERIFY_CA) in MySQL SSL settings, clients ensure that they are connecting to the correct server, preventing man-in-the-middle attacks. The other options help with security but do not directly prevent interception attacks.

A full backup is mandatory before an upgrade to avoid data loss. Resetting logs, flushing transactions, or modifying strict mode does not protect against upgrade failures.

The CHECK TABLE command is used to verify the integrity of a table, ensuring that there is no corruption. It works with both MyISAM and InnoDB tables. Unlike REPAIR TABLE, which attempts to fix corrupt MyISAM tables, CHECK TABLE does not modify data—it simply reports issues. VALIDATE TABLE is not a valid MySQL command. ANALYZE TABLE helps optimize query performance by updating index statistics but does not verify table integrity.

MySQL Enterprise Monitor does not directly track queries inside triggers, since they execute as part of larger transactions. Stored procedures and buffer pool activities can be monitored through other tools.

The performance_schema system variable must be enabled for MySQL Enterprise Monitor to collect performance data. Other variables control logging, InnoDB locking, or background events but do not affect monitoring capabilities.

The general_log stores all queries in plain text, potentially exposing sensitive data if improperly secured. utf8mb4 is for character encoding, not security. Disabling binary logging affects replication but does not expose data, and STRICT_ALL_TABLES enforces stricter validation, improving security.

The SHOW PROCESSLIST command displays all active client connections, along with session details like user, host, command, time, and state. This helps administrators monitor database activity and identify slow or problematic connections. The other options are not valid MySQL commands for viewing active connections.

The keyring_encrypted_file plugin provides an additional layer of security by encrypting stored encryption keys, unlike keyring_file, which stores keys in plaintext. This helps protect against unauthorized access in case the keyring file is compromised. The plugin does not impact query performance, replication, or SSL requirements.

Crash-safe replication enables replicas to resume replication from the last successfully applied transaction rather than requiring a full re-synchronization. It uses the replica’s transaction position instead of just the binary log file position. Incremental backups, temporary tables, and adaptive buffering do not handle replication catch-up.

The sort_buffer_size variable determines the memory allocated per session for ORDER BY and GROUP BY sorting operations. join_buffer_size is used for joins that cannot use indexes, read_rnd_buffer_size improves random reads, and innodb_sort_buffer_size does not exist in MySQL 8.0.

Using the same datadir for multiple MySQL instances will cause data corruption due to concurrent access. Each instance must have its own unique datadir to function properly. Different configuration files are necessary, but they do not prevent corruption if the same datadir is used. Running multiple instances does not inherently improve performance or enable automatic failover.

Before upgrading to MySQL 8.0, you must run mysql_upgrade to check incompatible changes and ensure schema compatibility. Converting tables, enabling strict mode, or purging logs is not required for upgrades.

The tls_version variable in MySQL specifies which TLS versions are allowed. Setting this properly helps enforce security compliance by restricting outdated protocols. The other options do not exist in MySQL 8.0.

In DETECTING mode, MySQL Enterprise Firewall logs queries that do not match the allowlist but does not block them. Blocking occurs in ENFORCE mode.

To enable SSL connections, MySQL requires a certificate (ssl_cert), a private key (ssl_key), and a certificate authority file (ssl_ca). The other options are invalid MySQL settings.

A Mixed Backup Strategy balances full backups, incremental backups, and binary logs to ensure efficient recovery while minimizing storage usage. Layered recovery model is not a recognized term in MySQL. Combined snapshot plan and Sequential archive method do not describe standard MySQL backup strategies.

The InnoDB Shared Tablespace (or file-per-table tablespace) stores table and index data in .ibd files if file_per_table is enabled. The Undo Tablespace stores undo logs, the Data Dictionary manages metadata, and the Tablespace System contains global InnoDB components.

The innodb_thread_concurrency variable controls the maximum number of concurrent threads that InnoDB can execute at any time. A value of 0 allows unlimited concurrency, but setting an optimal value can improve performance. thread_cache_size manages thread reuse, max_connections limits client connections, and performance_schema_max_threads affects Performance Schema monitoring, not execution concurrency.

Group Communication System (GCS) handles automatic primary selection in case of failure. MySQL Router, Cluster Monitor, and Transaction Coordinator do not control primary node elections.

The rsync -av command safely copies MySQL raw data files, preserving ownership and permissions. mysqldump and mysqlpump perform logical backups instead. cp –recursive –fast is not an optimal method for ensuring consistency in database backups.

The correct syntax for granting all privileges on a database is GRANT ALL PRIVILEGES ON database. TO user@host*. The ALL keyword alone is invalid, and the TO clause must be placed after specifying the database. Using incorrect keyword order results in a syntax error.

The correct way to check MySQL status is systemctl status mysqlserver. The other options reference incorrect MySQL service names.

The keyring_kms plugin allows MySQL 8.0 to integrate with an external Key Management System (KMS), ensuring encryption keys are securely managed outside the database server. The other options are either invalid or do not exist as MySQL keyring plugins.

The mysqld –initialize-insecure command initializes the data directory without setting a root password, making it easier for automation. The other options are invalid or do not exist in MySQL 8.0.

When a conflicting update occurs in multisource replication, MySQL stops the affected channel, requiring manual intervention to resolve conflicts. MySQL does not retry, merge, or discard transactions automatically, as this could lead to data inconsistency across replication sources.

The –defaults-file option lets users specify a custom configuration file for each MySQL instance, ensuring unique datadir, port, socket, and log files. The –default-authentication-plugin option sets the authentication plugin, –default-tmp-storage-engine specifies the temporary storage engine, and –default-storage-engine sets the default table storage engine but does not configure multiple instances.

mysqld_safe is a wrapper script that starts the MySQL server (mysqld) with enhanced crash recovery capabilities. If mysqld crashes unexpectedly, mysqld_safe attempts to restart it automatically, ensuring high availability. This tool also allows logging options and security settings to be configured at startup. It is unrelated to query execution safety, deadlock detection, or storage engine functionality, making those choices incorrect.

Host-based authentication in MySQL allows administrators to specify which IP addresses or hostnames can connect to a given user account. This is managed through the GRANT statement, which can be configured to permit or deny access based on client IP. The bind_address option controls which network interfaces MySQL listens on but does not restrict specific clients. The skip_networking option disables network access entirely, which is not practical for remote connections. SSL/TLS encryption secures connections but does not control access at the IP level.

MySQL Enterprise Monitor gathers query performance data using Performance Schema, which provides real-time insights into resource-intensive queries. It does not rely on binary logs, OS metrics, or response time indexing.

In multisource replication, stopping a single replication channel does not affect others. Each channel operates independently, meaning other active channels continue replicating. MySQL does not restart the server, and unprocessed transactions remain in relay logs until applied.

The Tablespace Autoextend feature automatically increases storage capacity when a tablespace reaches its limit, preventing unexpected failures. Other options do not directly manage storage space.

A SELECT DISTINCT query benefits from indexing because MySQL can efficiently eliminate duplicate values using sorted index data. DELETE and INSERT are slowed by indexes due to the additional maintenance required. ALTER TABLE operations that change indexes can also be slow, but they are not affected by an index in the same way SELECT DISTINCT is.

When replication stops, SHOW REPLICA STATUS reveals thread failures, error codes, and relay log positions. The master status and binary logs do not diagnose replica-side issues, and enabling relay log info tracking does not directly show errors.

Global Transaction Identifiers (GTIDs) uniquely identify each transaction across all servers, ensuring seamless failover and recovery. This avoids manual log file positioning issues found in traditional binary log replication. GTIDs do not compress logs, handle failover alone, or allow unordered execution.

When using file-per-table mode, MySQL creates a separate tablespace file (.ibd) for each table, which allows better space management and efficient storage reclamation after table truncation or deletion. Foreign keys and transactions remain supported, and redo logs are shared across all tablespaces. Metadata is stored in data dictionary tables, not in individual directories.

The information_schema.innodb_trx table shows active transactions, and sorting by trx_started helps identify the oldest blocking transaction. The INNODB STATUS command provides summary information, performance_schema.transactions does not exist, and PROCESSLIST does not show detailed transaction times.

In parallel replication, MySQL ensures consistency by using write-set dependencies, which allow independent transactions to be executed in parallel while maintaining correct commit order. The SQL thread does not force strict ordering, and the I/O thread does not apply events.

The START REPLICA command (formerly START SLAVE) is used to initiate replication, allowing the replica to start retrieving and applying transactions from the primary.

When require_secure_transport is enabled, MySQL rejects all client connections that are not using TLS/SSL encryption. This ensures that sensitive data such as credentials and queries are transmitted securely. The setting does not limit connections to localhost, block persistent connections, or disable user authentication.

The innodb_log_file_size option controls the maximum size of each log file for InnoDB. It is placed under the [mysqld] section, not under logging or other options.

The IGNORE rule prevents specific SQL statements or actions from being logged in the audit log. Other options do not exist in MySQL 8.0.

Global Transaction Identifiers (GTIDs) provide a unique identifier for every transaction executed on a MySQL server, simplifying replication management. GTID-based replication ensures that transactions are not applied multiple times and allows for easier failover without complex binlog position tracking. It is fully compatible with InnoDB, which supports transactions. MyISAM does not support GTID-based replication because it lacks transactional consistency.

The default system variables are stored in /etc/mysql/mysql-global.cnf, defining server-wide configurations. The other options reference incorrect or non-existent configuration files.

Handler_read_rnd_next measures the number of sequential row reads, which indicates full table scans rather than indexed searches. Innodb_index_stats_scan does not exist in MySQL. Performance_schema_events tracks query execution, but not index scans. Index_merge_cost_factor is a cost model parameter, not a statistic.