There is a problem with the slave replicating from the master. Which statement describes the cause of the problem?

Question

Options

• AThe log_bin variable is set to OFF on the slave.
• Bserver_id is not unique
• CThe max_connections variable on the slave needs to be increased.
• DThe shared_memory_base_name variable must match the master.
• EThe version of the slave is newer that the version of the master.

• A
  76% (39)
• B
  2% (1)
• C
  12% (6)
• D
  4% (2)
• E
  6% (3)

Explanation

Binary logging (log_bin) must be enabled for MySQL replication to function. The slave replicates by reading the master's binary log - if log_bin is OFF (either on the master or on a slave acting as an intermediate master in chained replication), there are no binary log events to read and apply, which breaks the replication chain entirely.

Why the distractors are wrong:

• B - A non-unique server_id can cause replication loops or events being ignored, but MySQL will still attempt replication; it's a misconfiguration, not a showstopper in the same way as no binary log at all.
• C - max_connections affects client connections, not the dedicated replication I/O thread, which has its own reserved connection slot.
• D - shared_memory_base_name governs Windows shared-memory IPC between local processes; it has no bearing on network-based master-slave replication.
• E - MySQL explicitly supports replicas running a newer version than the master (forward compatibility); it's the reverse (older slave, newer master) that causes problems.

Memory tip: Think "no log, no replicate" - if the binary log is OFF, the slave has nothing to read. Associate log_bin = OFF with a source that has gone silent.

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