Note
This view is available starting with V4.0.0.
Overview
Displays the histogram data (endpoints of each histogram) for the partitions of all partitioned tables in the current tenant.
Columns
Field Name |
Type |
Whether can be NULL |
Description |
|---|---|---|---|
| OWNER | varchar(128) | NO | Owner of the table |
| TABLE_NAME | varchar(128) | NO | Table name |
| PARTITION_NAME | varchar(128) | NO | Partitioned table name |
| COLUMN_NAME | varchar(128) | NO | Column name |
| ENDPOINT_NUMBER | decimal(10,0) | NO | Bin number of histogram |
| ENDPOINT_VALUE | decimal(10,0) | NO | 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 | Actual value of the endpoint in the original format |
| ENDPOINT_REPEAT_COUNT | decimal(10,0) | NO | Endpoint Frequency (Only for hybrid histograms; set to 0 for other histogram types.) |
Sample query
The system tenant queries the histogram information of partitions in the partitioned table test_part_hist.
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
View table-level histogram statistics: DBA_TAB_HISTOGRAMS
View histogram statistics at the subpartition level: DBA_SUBPART_HISTOGRAMS
View table-level column statistics: DBA_TAB_STATISTICS
View global column statistics: DBA_TAB_COL_STATISTICS
View column statistics at the partition level: DBA_PART_COL_STATISTICS
View column statistics at the subpartition level: DBA_SUBPART_COL_STATISTICS
View index statistics: DBA_IND_STATISTICS
For information about how to collect statistics, see the following topics: