MC Which statement is NOT CORRECT? Block level striping as used in RAID 0 does not increase read performance. correct RAID level 5 strikes a balance between read and write performance, storage efficiency, and fault tolerance. incorrect RAID level 0 is used if performance is more important than fault tolerance. incorrect To store the same amount of data, RAID 1 needs twice the amount of storage capacity compared to RAID 0. incorrect
MC Given 2 tables R and S. Which of the following join strategies is described by the following algorithm:
denote S -> outer table
for every row s in S do {
for every row r in R do {
if r(a) = s(b) then join r with s and place in output buffer
}
} Nested loop join correct Sort-Merge join incorrect None of these joins incorrect Hash join incorrect
MC Which statement is NOT CORRECT? A primary element of a contingency plan is the quantification of recovery objectives in RTO and RPO, given the organization's strategic priorities. incorrect Current versions of SQL require a specific internal data model. correct The number of block accesses determines the performance, not the number of rows retrieved. incorrect It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because having multiple physical drives allows for parallel retrieval, which results in much more improved performance. incorrect
MC Which statement is CORRECT? Using error correcting codes for fault tolerance requires extra storage space, almost as much as when opting for disk mirroring. incorrect A DAS does not offer out-of-the-box capabilities for centralized storage management and sharing unused disk capacity across servers. correct Block level striping as used in RAID 0 does not increase read performance. incorrect Compared to SAN, a NAS is much less expensive and much simpler in soft- and hardware. However, it achieves performance similar to a NAS set-up. incorrect
MC Which statement is NOT CORRECT? A primary element of a contingency plan is the quantification of recovery objectives in RTO and RPO, given the organization's strategic priorities. incorrect Rolling upgrades are an example of how to avoid downtime in a cluster computing set-up. incorrect The only points of failure of a database system are the availability of database functionality and the availability of the data itself. correct The manual failover of DBMS functionality is a simple and not very expensive solution to guarantee the availability of DBMS functionality in case of a calamity. incorrect
MC Which statement is NOT CORRECT? It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because reliability can be improved by introducing some measure of data redundancy. incorrect With bit level data striping, every disk participates in each read or write operation. incorrect It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because having multiple physical drives allows for parallel retrieval, which results in much more improved performance. incorrect Using error correcting codes for fault tolerance requires extra storage space, almost as much as when opting for disk mirroring. correct
MC Statement 1: When opting for hard drive back-ups to maintain data availability in case of a calamity, the RPO depends on the underlying infrastructure. Choosing a SAN as storage subsystem might be a solution here, as it keeps the burden of data and backup related traffic from the LAN and from the servers.
Statement 2: Log shipping is a technique which is used for preserving the transaction context of a DBMS in case of a calamity. The remote DBMS used for replication can use the primary log for restoring transactions that were ongoing at the primary site.
Which statements are correct or wrong? Both statements are correct. incorrect Statement 1 is wrong, statement 2 is correct. correct Both statements are wrong. incorrect Statement 1 is correct, statement 2 is wrong. incorrect
MC Which statement is NOT CORRECT? A primary element of a contingency plan is the quantification of recovery objectives in RTO and RPO, given the organization's strategic priorities. incorrect The only points of failure of a database system are the availability of database functionality and the availability of the data itself. correct The manual failover of DBMS functionality is a simple and not very expensive solution to guarantee the availability of DBMS functionality in case of a calamity. incorrect Rolling upgrades are an example of how to avoid downtime in a cluster computing set-up. incorrect
MC Which statement is NOT CORRECT? Indexing makes it harder to enforce uniqueness on a (combination of) column(s). correct An index can be used to create a physical ordering of rows. incorrect Index creation can help improve the performance of join queries. incorrect An index implies a logical ordering of the rows in a table. incorrect
MC Which statement is CORRECT? Although SCSI has been a popular medium for connecting storage devices to servers and/or processors in the past, nowadays, it is not used anymore for high performance and high capacity workstations and servers. incorrect The more selective a query predicate's FF, the less desirable it is to use the index on the corresponding attribute type in the access plan. incorrect Current versions of SQL require a specific internal data model. incorrect It is often more efficient to combine multiple smaller physical disk drives into one larger logical drive because reliability can be improved by introducing some measure of data redundancy. correct