某珠宝商店失窃,甲、乙、丙、丁四人涉嫌被拘审。四人的口供如下:甲:案犯是丙。乙:丁是罪犯。丙:如果我作案那么丁是主犯。丁:作案的不是我。四个口供中只有一个是假的。如果以上断定为真,则以下()项是真的。
A. 说假话的是丙,作案的是丙
B. 说假话的是甲,作案的是甲
C. 说假话的是乙,作案的是丙
D. 说假话的是丁,作案的是丙和丁
E. 说假话的是甲,作案的是乙
Full Atomicity, Consistency, Isolation, Durability (ACID) compliance is a necessity for a new application, which heavily reads and writes data. This requires the following config file options: Sync_binlog=1 Innodb_flush_log_at_trx_commit=1 Innodb_doublewrite=1 However, this configuration is expected to introduce disk I/O overhead. What three changes will reduce disk I/O overheads?()
A. Use of soft links for database directories on the same physical disk
B. Use of delay_key_write=ON for batch index update
C. Allocation of RAM to the buffer pool such that more of the data can fit in RAM
D. Placement of InnoDB log files and datadir on separate physical disks
E. Use of separate directories on the same physical disk for log files and data file