Charts represent tables of data ________

When you put objects in Amazon S3, what is the indication that an object was successfully stored?

A. A HTTP 200 result code and MD5 checksum, taken together, indicate that the operation was successful. B. Amazon S3 is engineered for 99.999999999% durability. Therefore there is no need to confirm that data was inserted. C. A success code is inserted into the S3 object metadata. D. Each S3 account has a special bucket named _s3_logs. Success codes are written to this bucket with a timestamp and checksum.

The following multiversion concurrency control has been proposed.

Reads are satisfied using the (committed) version of the database that existed when the transaction made its first read request. Writes are controlled by long-duration write locks on tables. Does the control always produce serializable schedules? If not, give a nonserializable schedule it might produce.