The option which delays index flushing for slave server is . . . . . . . .

Solution (By Examveda Team)

This question is about MySQL slave servers and how they handle index updates. Let's break it down:
* Slave Server: A MySQL server that replicates data from a master server.
* Index Flushing: The process of writing changes to the indexes to disk. Indexes are used for faster data retrieval.
The options in the question are different configuration settings that control index flushing on a slave server:
* Option A: -delay-write-key=ALL : This option delays the writing of all index changes to disk. This can improve performance but also increase the risk of data loss if the server crashes before the changes are written.
* Option B: -delay-key-write=ALL : This is the correct answer. It delays the writing of index changes to disk but only for non-transactional tables. This offers a balance between performance and data safety.
* Option C: -key-write-delay=NONE : This option means index changes are written to disk immediately. This is generally not recommended as it can slow down performance.
* Option D: -key-delay-write=NONE : Similar to Option C, this option writes index changes to disk immediately, which can impact performance.
In summary, Option B: -delay-key-write=ALL is the best choice to delay index flushing for a slave server, as it provides a balance between performance and data integrity.