Which statement about value compression is correct?
A. To use value compression, you must have a license for the DB2 Storage Optimization Feature.
B. Value compression uses a page-level dictionary-based compression algorithm to compress data based on repetition of values found in a single column.
C. Value compression involves removing duplicate entries for a value, only storing one copy, and keeping track of the location of any references to the stored copy.
D. When value compression is used, the byte count of compressed NULLs, zeros, and blanks might be larger than that of the uncompressed version of the same values.
正解:C
質問 2:
What values can be assigned to the HADR_SYNCMODE configuration parameter?
A. SYNC, NOSYNC, ASYNC, and SUPERASYNC
B. SYNC, NEARSYNC, ASYNC, and NOSYNC
C. SYNC, ASYNC, SEMISYNC, and SUPERASYNC
D. SYNC, NEARSYNC, ASYNC, and SUPERASYNC
正解:D
質問 3:
The following query is executed frequently against the SALES table: SELECT sales_id, sales_date, sales_person FROM sales; If data in the SALES_ID column is unique, which statement will create an index for optimal query performance and ensure uniqueness of the SALES_ID column?
A. CREATE INDEX sales_idx ON sales (sales_id, sales_date, sales_person)
B. CREATE UNIQUE INDEX sales_idx ON sales (sales_id) INCLUDE (sales_date, sales_person)
C. CREATE UNIQUE INDEX sales_idx ON sales (sales_id, sales_date, sales_person)
D. CREATE INDEX sales_idx ON sales (sales_id) INCLUDE (sales_date, sales_person)
正解:B
質問 4:
Which is a poor choice for a clustering dimension of a multidimensional clustering (MDC) table?
A. Columns with low cardinalities
B. Columns involved in equality or range predicate queries
C. Columns with high cardinalities
D. Columns involved in roll-in or roll-out of data
正解:C
質問 5:
Which statement about block indexes is correct?
A. Prefetching of data pages relies on sequential detection when block indexes are used.
B. Block indexes improve performance when data is not clustered on sequential pages.
C. The records for each block are retrieved using a mini-relational scan of saved data pages.
D. Because of their large size, block indexes are extremely efficient.
正解:A
質問 6:
Which statement about compression dictionaries is FALSE?
A. Table-level dictionaries are automatically created or recreated as by the database manager as pages are filled.
B. Page-level dictionaries are stored in hidden rows within the table.
C. Table-level dictionaries are stored in hidden rows within the table.
D. Page-level dictionaries are automatically created or recreated by the database manager as pages are filled.
正解:A
解説: (Pass4Test メンバーにのみ表示されます)