GitHub user gatorsmile opened a pull request:
https://github.com/apache/spark/pull/15136
[SPARK-17581] [SQL] Invalidate Statistics After Some ALTER TABLE Commands
### What changes were proposed in this pull request?
In the recent statistics-related work, our focus is on how to generate and
store the statistics. After `Analyze Table` commands, the statistics will not
be changed unless users run the command again. However, Hive behaves
differently. For example, `ALTER TABLE SET LOCATION` will invalidate the
statistics, including `numRows` and `rawDataSize`.
```
hive> describe formatted t2;
...
Location: hdfs://6b68a24121f4:9000/user/hive/warehouse/t2
Table Type: MANAGED_TABLE
Table Parameters:
COLUMN_STATS_ACCURATE true
numFiles 4
numRows 2
rawDataSize 2
totalSize 4
transient_lastDdlTime 1464590855
...
```
```
hive> alter table t2 set location
'hdfs://6b68a24121f4:9000/user/hive/warehouse/t1';
OK
Time taken: 0.113 seconds
```
```
hive> describe formatted t2;
...
Location: hdfs://6b68a24121f4:9000/user/hive/warehouse/t1
Table Type: MANAGED_TABLE
Table Parameters:
COLUMN_STATS_ACCURATE false
last_modified_by root
last_modified_time 1474178025
numFiles 4
numRows -1
rawDataSize -1
totalSize 4
...
```
This PR tries to fix the related issues.
### How was this patch tested?
Added test cases.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/gatorsmile/spark
invalidateStatsAfterAlterTable
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/15136.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #15136
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