Note
This view is available starting with V4.0.0.
Purpose
This view displays histogram data of partitions in 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 standardized endpoint value of the bucket. |
| ENDPOINT_ACTUAL_VALUE | text | NO | The actual string value of the bucket endpoint (non-standardized). |
| ENDPOINT_ACTUAL_VALUE_RAW | text | NO | The endpoint value in the original format. |
| ENDPOINT_REPEAT_COUNT | decimal(10,0) | NO | The endpoint frequency. For mixed histograms, this value indicates the frequency of the endpoint. For other histogram types, this value is 0. |
Sample query
Query the histogram information of partitions in the test_part_hist 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 table-level histogram statistics: DBA_TAB_HISTOGRAMS
Query subpartition-level histogram statistics: DBA_SUBPART_HISTOGRAMS
Query table-level column statistics: DBA_TAB_STATISTICS
Query global-level column statistics: DBA_TAB_COL_STATISTICS
Query partition-level column statistics: DBA_PART_COL_STATISTICS
Query subpartition-level column statistics: DBA_SUBPART_HISTOGRAMS
Query index statistics: DBA_IND_STATISTICS
For information about how to collect statistics, see the following topics: