[IMPALA-5308] SHOW TABLE STATS for Kudu tables is confusing

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.8.0
• Fix Version/s: Impala 4.0.0
• Component/s: Frontend
• Labels: kudu
• Target Version: Product Backlog
• Epic Color: ghx-label-9
• Assignee: Tamas Mate
• Reporter: Matthew Jacobs
• Created: 11/May/17 20:31
• Updated: 22/Apr/20 07:13
• Resolved: 22/Apr/20 07:13

Description

SHOW TABLE STATS for Kudu tables shows all Kudu tablets and explicitly shows the #rows are -1, because we don't support per-partition or per-tablet stats (see IMPALA-2830).

However, we do have table statistics (# rows) and that doesn't show up in the SHOW TABLE STATS output, which is confusing. The table stats does show up in the DESCRIBE EXTENDED output.

[localhost:21000] > show table stats tdata;
Query: show table stats tdata
+--------+-----------+----------+----------------------------------+------------+
| # Rows | Start Key | Stop Key | Leader Replica                   | # Replicas |
+--------+-----------+----------+----------------------------------+------------+
| -1     |           | 00000001 | mj-desktop.ca.cloudera.com:31201 | 3          |
| -1     | 00000001  | 00000002 | mj-desktop.ca.cloudera.com:31202 | 3          |
| -1     | 00000002  |          | mj-desktop.ca.cloudera.com:31201 | 3          |
+--------+-----------+----------+----------------------------------+------------+
Fetched 3 row(s) in 0.02s
[localhost:21000] > describe extended tdata;
Query: describe extended tdata
+------------------------------+-------------------------------------------------+-------------------------------------------+
| name                         | type                                            | comment                                   |
+------------------------------+-------------------------------------------------+-------------------------------------------+
| # col_name                   | data_type                                       | comment                                   |
|                              | NULL                                            | NULL                                      |
| id                           | int                                             | NULL                                      |
...
                          |
|                              | NULL                                            | NULL                                      |
| # Detailed Table Information | NULL                                            | NULL                                      |
| Database:                    | default                                         | NULL                                      |
| Owner:                       | mj                                              | NULL                                      |
| CreateTime:                  | Mon May 08 11:16:29 PDT 2017                    | NULL                                      |
| LastAccessTime:              | UNKNOWN                                         | NULL                                      |
| Protect Mode:                | None                                            | NULL                                      |
| Retention:                   | 0                                               | NULL                                      |
| Location:                    | hdfs://localhost:20500/test-warehouse/tdata     | NULL                                      |
| Table Type:                  | MANAGED_TABLE                                   | NULL                                      |
| Table Parameters:            | NULL                                            | NULL                                      |
|                              | DO_NOT_UPDATE_STATS                             | true                                      |
|                              | STATS_GENERATED_VIA_STATS_TASK                  | true                                      |
|                              | kudu.master_addresses                           | 127.0.0.1                                 |
|                              | kudu.table_name                                 | impala::default.tdata                     |
|    ==========>   | numRows                                         | 1500                                      |

Issue Links

• relates to: IMPALA-2830 Partition/tablet statistics for Kudu tables