Which two statements are true about the logical storage structure of an Oracle database?
A.
An extent contains data blocks that are always physically contiguous on disk.
B.
An extent can span multiple segments,
C.
Each data block always corresponds to one operating system block.
D.
It is possible to have tablespaces of different block sizes.
E.
A data block is the smallest unit of I/O in data files.
Explanation:
http://docs.oracle.com/cd/E11882_01/server.112/e40540/logical.htm#CNCPT250
D,E
According to the link, “A data block is the minimum unit of database I/O.”
So, ans is DE
Isn’t A also correct? For this kind of question is there 3 correct answer so if you choose any two out from this you also get the question right?
A is not correct. It should be logically contiguous. However, does anyone know B is correct or not?
D, E
B is wrong
https://docs.oracle.com/database/121/CNCPT/logical.htm#i10251
Answers : D and E
I tried to provide explanation below I hope it will be helpfull
https://docs.oracle.com/cd/E11882_01/server.112/e40540/logical.htm#CNCPT3000
A : An extent is a set of logically contiguous data blocks allocated for storing a specific type of information
B: a segment can include extents from multiple data files, as shown in Figure 12-2
C:?
D:https://docs.oracle.com/cd/B28359_01/server.111/b28310/tspaces003.htm
Specifying Nonstandard Block Sizes for Tablespaces
E:This is know by everyone 🙂 you can see it from the link
https://docs.oracle.com/cd/E11882_01/server.112/e40540/logical.htm#CNCPT3000
Figure 12-1 Logical and Physical Storage
D, E
DE
D??
CREATE TABLESPACE TEST LOGGING DATAFILE SIZE 100M AUTOEXTEND ON NEXT 10M MAXSIZE UNLIMITED blocksize 16K
*
ERROR at line 1:
ORA-29339: tablespace block size 16384 does not match configured block sizes
You can use the parameter DB_16K_CACHE_SIZE
D and E
B is not correct, Segment can span multiple extents, not the opposite.
see figure 12.1
http://docs.oracle.com/cd/E11882_01/server.112/e40540/logical.htm#CNCPT301
According to the Crown foot relationship between segment —- extent. So an extent can just belong to a segment.
D: https://docs.oracle.com/database/121/CNCPT/logical.htm#CNCPT301
E: Is a Logical Storage Structures, not physical.