Oracle 视图 DBA_HIST_DB_CACHE_ADVICE 官方解释，作用，如何使用详细说明

SNAP_ID

NUMBER

NOT NULL

Unique snapshot ID

DBID

NUMBER

NOT NULL

Database ID for the snapshot

INSTANCE_NUMBER

NUMBER

NOT NULL

Instance number for the snapshot

BPID

NUMBER

NOT NULL

Buffer Pool identifier (ranges from 1 to 8)

BUFFERS_FOR_ESTIMATE

NUMBER

NOT NULL

Cache size for prediction (in terms of buffers)

NAME

VARCHAR2(20)

Buffer pool name

BLOCK_SIZE

NUMBER

Block size in bytes for buffers in the pool (the standard block size, the power of 2 nonstandard block sizes, 2048, 4096, 8192, 16384, or 32768)

ADVICE_STATUS

VARCHAR2(3)

Status of the advisory:

• ON – Currently running

• OFF – Disabled (the estimates are historical and calculated when last enabled)

SIZE_FOR_ESTIMATE

NUMBER

Cache size for prediction (in megabytes)

SIZE_FACTOR

NUMBER

Size factor with respect to the current cache size

PHYSICAL_READS

NUMBER

Physical reads for the cache size

BASE_PHYSICAL_READS

NUMBER

Base physical reads for the cache size

ACTUAL_PHYSICAL_READS

NUMBER

Actual physical reads for the cache size

ESTD_PHYSICAL_READ_TIME

NUMBER

Estimated physical read time for the cache size

CON_DBID

NUMBER

The database ID of the PDB for the sampled session

CON_ID

NUMBER

The ID of the container that CON_DBID identifies. Possible values include:

• 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

• 1: This value is used for rows containing data that pertain to only the root

• n: Where n is the applicable container ID for the rows containing data