Note
This view is available starting with V4.0.0.
Purpose
This view displays the histogram data of the partitions of all partitioned tables in the current tenant (the endpoints of each histogram).
Columns
Column |
Type |
Nullable |
Description |
|---|---|---|---|
| OWNER | varchar(128) | NO | The owner of the table. |
| TABLE_NAME | varchar(128) | NO | The name of the table. |
| PARTITION_NAME | varchar(128) | NO | The name of the partitioned table. |
| COLUMN_NAME | varchar(128) | NO | The name of the column. |
| ENDPOINT_NUMBER | decimal(10,0) | NO | The bucket number of the histogram. |
| ENDPOINT_VALUE | decimal(10,0) | NO | The normalized endpoint value of the bucket. |
| ENDPOINT_ACTUAL_VALUE | text | NO | The actual string value of the endpoint of the bucket (non-normalized). |
| ENDPOINT_ACTUAL_VALUE_RAW | text | NO | The endpoint value in the original format. |
| ENDPOINT_REPEAT_COUNT | decimal(10,0) | NO | The endpoint frequency (only applicable to mixed histograms; set to 0 for other histogram types). |
Sample query
Query the histogram information of the partitions of the test_part_hist partitioned table in the sys tenant.
obclient [oceanbase]> SELECT * FROM oceanbase.DBA_PART_HISTOGRAMS WHERE TABLE_NAME ='test_part_hist';
The query result is as follows:
+----------+----------------+----------------+-------------+-----------------+----------------+-----------------------+---------------------------+-----------------------+
| OWNER | TABLE_NAME | PARTITION_NAME | COLUMN_NAME | ENDPOINT_NUMBER | ENDPOINT_VALUE | ENDPOINT_ACTUAL_VALUE | ENDPOINT_ACTUAL_VALUE_RAW | ENDPOINT_REPEAT_COUNT |
+----------+----------------+----------------+-------------+-----------------+----------------+-----------------------+---------------------------+-----------------------+
| test | test_part_hist | p0 | value | 250 | NULL | 100 | 04053F0064 | 50 |
| test | test_part_hist | p0 | value | 200 | NULL | 8 | 04053F0008 | 50 |
| test | test_part_hist | p0 | value | 150 | NULL | 6 | 04053F0006 | 50 |
| test | test_part_hist | p0 | value | 100 | NULL | 4 | 04053F0004 | 50 |
| test | test_part_hist | p0 | value | 50 | NULL | 2 | 04053F0002 | 50 |
| test | test_part_hist | p0 | category | 250 | NULL | 'B' | 16022DFF014200 | 200 |
| test | test_part_hist | p0 | category | 50 | NULL | 'A' | 16022DFF014100 | 50 |
| test | test_part_hist | p1 | value | 250 | NULL | 9 | 04053F0009 | 50 |
| test | test_part_hist | p1 | value | 200 | NULL | 7 | 04053F0007 | 50 |
| test | test_part_hist | p1 | value | 150 | NULL | 5 | 04053F0005 | 50 |
| test | test_part_hist | p1 | value | 100 | NULL | 3 | 04053F0003 | 50 |
| test | test_part_hist | p1 | value | 50 | NULL | 1 | 04053F0001 | 50 |
| test | test_part_hist | p1 | category | 250 | NULL | 'B' | 16022DFF014200 | 250 |
| test | test_part_hist | p2 | value | 250 | NULL | 100 | 04053F0064 | 50 |
| test | test_part_hist | p2 | value | 200 | NULL | 8 | 04053F0008 | 50 |
| test | test_part_hist | p2 | value | 150 | NULL | 6 | 04053F0006 | 50 |
| test | test_part_hist | p2 | value | 100 | NULL | 4 | 04053F0004 | 50 |
| test | test_part_hist | p2 | value | 50 | NULL | 2 | 04053F0002 | 50 |
| test | test_part_hist | p2 | category | 250 | NULL | 'B' | 16022DFF014200 | 200 |
| test | test_part_hist | p2 | category | 50 | NULL | 'A' | 16022DFF014100 | 50 |
| test | test_part_hist | p3 | value | 250 | NULL | 9 | 04053F0009 | 50 |
| test | test_part_hist | p3 | value | 200 | NULL | 7 | 04053F0007 | 50 |
| test | test_part_hist | p3 | value | 150 | NULL | 5 | 04053F0005 | 50 |
| test | test_part_hist | p3 | value | 100 | NULL | 3 | 04053F0003 | 50 |
| test | test_part_hist | p3 | value | 50 | NULL | 1 | 04053F0001 | 50 |
| test | test_part_hist | p3 | category | 250 | NULL | 'B' | 16022DFF014200 | 250 |
+----------+----------------+----------------+-------------+-----------------+----------------+-----------------------+---------------------------+-----------------------+
26 rows in set
References
Query the histogram statistics at the table level: DBA_TAB_HISTOGRAMS
Query the histogram statistics at the subpartition level: DBA_SUBPART_HISTOGRAMS
Query the column statistics at the table level: DBA_TAB_STATISTICS
Query the column statistics at the global level: DBA_TAB_COL_STATISTICS
Query the column statistics at the partition level: DBA_PART_COL_STATISTICS
Query the column statistics at the subpartition level: DBA_SUBPART_COL_STATISTICS
Query the index statistics: DBA_IND_STATISTICS
For information about how to collect statistics, see the following topics: