ALL_TAB_COL_STATISTICS

ALL_TAB_COL_STATISTICS displays column statistics and histogram information extracted from "ALL_TAB_COLUMNS".

Related Views

  • DBA_TAB_COL_STATISTICS displays such information extracted from "DBA_TAB_COLUMNS".

  • USER_TAB_COL_STATISTICS displays such information extracted from "USER_TAB_COLUMNS". This view does not display the OWNER column.

Column Datatype NULL Description

OWNER

VARCHAR2(128)

  

Owner of the table

TABLE_NAME

VARCHAR2(128)

  

Name of the table

COLUMN_NAME

VARCHAR2(128)

  

Column name

NUM_DISTINCT

NUMBER

  

Number of distinct values in the column

LOW_VALUE

RAW(1000)

  

Low value in the column

HIGH_VALUE

RAW(1000)

  

High value in the column

DENSITY

NUMBER

  

If a histogram is available on COLUMN_NAME, then this column displays the selectivity of a value that spans fewer than 2 endpoints in the histogram. It does not represent the selectivity of values that span 2 or more endpoints.

If a histogram is not available on COLUMN_NAME, then the value of this column is 1/NUM_DISTINCT.

NUM_NULLS

NUMBER

  

Number of NULLs in the column

NUM_BUCKETS

NUMBER

  

Number of buckets in histogram for the column

LAST_ANALYZED

DATE

  

Date on which this column was most recently analyzed

SAMPLE_SIZE

NUMBER

  

Sample size used in analyzing this column

GLOBAL_STATS

VARCHAR2(3)

  

Indicates whether statistics were gathered for the table as a whole (global statistics) (YES) or they were not gathered (NO). Note that for partitioned tables, global statistics and partition statistics are estimated from underlying partition and subpartition statistics, respectively, when set to NO.

USER_STATS

VARCHAR2(3)

  

Indicates whether statistics were entered directly by the user (YES) or not (NO)

NOTES

VARCHAR2(41)

  

Describes some additional properties of the statistics. For example, if the value is INCREMENTAL, the global statistics are derived from synopses, that is, the global statistics are incrementally maintained.

AVG_COL_LEN

NUMBER

  

Average length of the column (in bytes)

HISTOGRAM

VARCHAR2(15)

  

Indicates existence/type of histogram:

  • NONE

  • FREQUENCY

  • HEIGHT BALANCED

  • HYBRID

  • TOP-FREQUENCY

SCOPE

VARCHAR2(7)

  

The value is SHARED for statistics gathered on any table other than global temporary tables.

For a global tempoary table, the possible values are:

  • SESSION - Indicates that the statistics are session-specific

  • SHARED - Indicates that the statistics are shared across all sessions

See Oracle Database PL/SQL Packages and Types Reference for information about using the GLOBAL_TEMP_TABLE_STATS preference of the DBMS_STATS package to control whether to gather session or shared statistics for global temporary tables.

See Also: