Note
This view is available starting with V4.0.0.
Purpose
This view displays the column statistics and histogram information of all partitioned tables in the current tenant.
Columns
Column |
Type |
Nullable |
Description |
|---|---|---|---|
| OWNER | varchar(128) | NO | The owner of the partitioned table. |
| TABLE_NAME | varchar(128) | NO | The name of the table. |
| PARTITION_NAME | varchar(128) | NO | The name of the partition. |
| COLUMN_NAME | varchar(128) | NO | The name of the column. |
| NUM_DISTINCT | decimal(10,0) | NO | The number of distinct values in the column. |
| LOW_VALUE | varchar(128) | NO | The minimum value in the column. |
| HIGH_VALUE | varchar(128) | NO | The maximum value in the column. |
| DENSITY | decimal(10,0) | NO | The density of the column. If a histogram is available for the COLUMN_NAME column, this column displays the selectivity of values that span fewer than 2 endpoints in the histogram. It does not represent the selectivity of values that span 2 or more endpoints. If no histogram is available for the COLUMN_NAME column, the value of this column is 1/NUM_DISTINCT. |
| NUM_NULLS | decimal(10,0) | NO | The number of NULL values in the column. |
| NUM_BUCKETS | decimal(10,0) | NO | The number of buckets in the histogram of the column. |
| LAST_ANALYZED | datetime(6) | NO | The date when the column was last analyzed. |
| SAMPLE_SIZE | decimal(10,0) | NO | The sample size used to analyze the column. |
| GLOBAL_STATS | varchar(3) | NO | Indicates whether statistics have been collected:
|
| NOTES | varchar(80) | NO | Describes some additional properties of the statistics:
This column can be used to determine whether the sketch in the adaptive sampling format has been completely purged and properly cleared. |
| AVG_COL_LEN | decimal(10,0) | NO | The average length of the column in bytes. |
| HISTOGRAM | varchar(15) | NO | Indicates the type of histogram:
|
Sample query
Query the column statistics and histogram information of the partitions of the t_subpart partitioned table in the current tenant.
obclient [oceanbase]> SELECT * FROM oceanbase.DBA_PART_COL_STATISTICS WHERE TABLE_NAME='t_subpart';
The query result is as follows:
+-------+------------+----------------+-------------+--------------+-----------+------------+--------------+-----------+-------------+----------------------------+-------------+--------------+------------+-------+-------------+-----------+
| OWNER | TABLE_NAME | PARTITION_NAME | COLUMN_NAME | NUM_DISTINCT | LOW_VALUE | HIGH_VALUE | DENSITY | NUM_NULLS | NUM_BUCKETS | LAST_ANALYZED | SAMPLE_SIZE | GLOBAL_STATS | USER_STATS | NOTES | AVG_COL_LEN | HISTOGRAM |
+-------+------------+----------------+-------------+--------------+-----------+------------+--------------+-----------+-------------+----------------------------+-------------+--------------+------------+-------+-------------+-----------+
| test | t_subpart | p0 | c1 | 3540 | 0 | 9999 | 0.0002824859 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3334 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p0 | c2 | 1012 | 0 | 999 | 0.0009881423 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3334 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p0 | c3 | 2030 | 0 | 1999 | 0.0004926108 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3334 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p1 | c1 | 3308 | 1 | 9997 | 0.0003022975 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p1 | c2 | 1012 | 0 | 999 | 0.0009881423 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p1 | c3 | 2030 | 0 | 1999 | 0.0004926108 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p2 | c1 | 3230 | 2 | 9998 | 0.0003095975 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p2 | c2 | 1012 | 0 | 999 | 0.0009881423 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
| test | t_subpart | p2 | c3 | 2030 | 0 | 1999 | 0.0004926108 | 0 | 5 | 2025-03-17 15:30:30.152256 | 3333 | NO | NO | NULL | 20 | HYBRID |
+-------+------------+----------------+-------------+--------------+-----------+------------+--------------+-----------+-------------+----------------------------+-------------+--------------+------------+-------+-------------+-----------+
9 rows in set
References
Query column statistics at the table level: DBA_TAB_STATISTICS
Query column statistics at the global level: DBA_TAB_COL_STATISTICS
Query column statistics at the subpartition level: DBA_SUBPART_COL_STATISTICS
Query histogram statistics at the table level: DBA_TAB_HISTOGRAMS
Query histogram statistics at the partition level: DBA_PART_HISTOGRAMS
Query histogram statistics at the subpartition level: DBA_SUBPART_HISTOGRAMS
Query index statistics: DBA_IND_STATISTICS
For information about how to collect statistics, see the following topics: