[IMPALA-7876] COMPUTE STATS TABLESAMPLE is not updating number of estimated rows

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 3.0
• Fix Version/s: Impala 4.0.0
• Component/s: Frontend
• Target Version: Impala 4.0.0
• Epic Color: ghx-label-2
• Assignee: Abhishek Rawat
• Reporter: Andre Araujo
• Created: 20/Nov/18 21:31
• Updated: 17/Nov/20 21:34
• Resolved: 17/Nov/20 21:18

Description

Running the command below seems to have no impact on the #rows stats.

[host:21000] default> COMPUTE STATS wide TABLESAMPLE SYSTEM(5);
Query: COMPUTE STATS wide TABLESAMPLE SYSTEM(100)
+-------------------------------------------+
| summary                                   |
+-------------------------------------------+
| Updated 1 partition(s) and 103 column(s). |
+-------------------------------------------+
WARNINGS: Ignoring TABLESAMPLE because the effective sampling rate is 100%.
The minimum sample size is COMPUTE_STATS_MIN_SAMPLE_SIZE=1.00GB and the table size 20.35GB
Fetched 1 row(s) in 43.67s

[host:21000] default> show table stats wide;
Query: show table stats wide
+-------+--------------+--------+---------+--------------+-------------------+---------+-------------------+-------------------------------------+
| #Rows | Extrap #Rows | #Files | Size    | Bytes Cached | Cache Replication | Format  | Incremental stats | Location                            |
+-------+--------------+--------+---------+--------------+-------------------+---------+-------------------+-------------------------------------+
| 0     | -1           | 84     | 20.35GB | NOT CACHED   | NOT CACHED        | PARQUET | false             | hdfs://ns1/user/hive/warehouse/wide |
+-------+--------------+--------+---------+--------------+-------------------+---------+-------------------+-------------------------------------+
Fetched 1 row(s) in 0.01s