[IMPALA-1028] Cardinality estimate is wrong for partitioned tables if we filter out all partitions

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 1.3.1
• Fix Version/s: Impala 1.4
• Assignee: Dimitris Tsirogiannis
• Reporter: Nong Li
• Created: 04/Jun/14 19:06
• Updated: 22/Jun/14 22:29
• Resolved: 16/Jun/14 23:57

Description

This only happens if all partitions are filtered out and we use the table estimate.

Query: explain select * from functional.alltypes where year = 100000
+------------------------------------------------------------------------+
| Explain String                                                         |
+------------------------------------------------------------------------+
| Estimated Per-Host Requirements: Memory=-9223372036854775808B VCores=0 |
|                                                                        |
| F01:PLAN FRAGMENT [PARTITION=UNPARTITIONED]                            |
|   01:EXCHANGE [PARTITION=UNPARTITIONED]                                |
|      hosts=3 per-host-mem=unavailable                                  |
|      tuple-ids=0 row-size=97B cardinality=7300                         |
|                                                                        |
| F00:PLAN FRAGMENT [PARTITION=RANDOM]                                   |
|   DATASTREAM SINK [FRAGMENT=F01, EXCHANGE=01, PARTITION=UNPARTITIONED] |
| 00:SCAN HDFSSCAN HDFS [functional.alltypes, PARTITION=RANDOM]          |
|      partitions=0/24 size=0B                                           |
|      table stats: 7300 rows total                                      |
|      column stats: all                                                 |
|      hosts=3 per-host-mem=0B                                           |
|      tuple-ids=0 row-size=97B cardinality=7300                         |
+------------------------------------------------------------------------+