You are using mysqlcheck for server maintenance. Which two statements are true? (Choose two.)

Question

Options

• AThe mysqlcheck --check --all-databases command takes table write locks while performing a
• BThe mysqlcheck --optimize --all-databases command reclaims free space from table files.
• CThe mysqlcheck --repair --all-databases command can repair an InnoDB corrupted table.
• DThe mysqlcheck command can be renamed mysqlrepair so that it repairs tables by default.
• EThe mysqlcheck --analyze --all-databases command performs a series of checks to spot eventual

• A
  3% (1)
• B
  17% (5)
• C
  10% (3)
• D
  70% (21)

Explanation

D is correct because mysqlcheck is a multi-call binary that changes its default operation based on what it's named: renaming it to mysqlrepair defaults to --repair, mysqlanalyze to --analyze, and mysqloptimize to --optimize - this is documented MySQL behavior. E is correct because mysqlcheck --analyze calls ANALYZE TABLE, which reads key distributions and stores statistics that the query optimizer uses, effectively performing analysis to identify eventual distribution inconsistencies.

A is wrong because --check acquires a read lock, not a write lock - write locks would block concurrent reads and would be far too disruptive for a check operation. B is wrong because mysqlcheck --optimize runs OPTIMIZE TABLE, which for InnoDB (the default engine) is remapped to ALTER TABLE ... FORCE and rebuilds the table in-place but does not reliably return free space to the OS from the .ibd file; true free-space reclamation applies to MyISAM, not InnoDB. C is wrong because REPAIR TABLE (called by --repair) is unsupported for InnoDB tables entirely - InnoDB uses crash recovery and backup restoration for corruption, not REPAIR TABLE.

Memory tip: Think "rename = reroute default" for D, and remember that InnoDB is immune to both --repair (C) and simple space reclamation (B) - InnoDB handles those concerns internally through its own crash recovery and tablespace management.

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