GitHub user wzhfy opened a pull request:
https://github.com/apache/spark/pull/18248
Separation between spark's stats and hive's stats
## What changes were proposed in this pull request?
Currently, hive's stats are read into `CatalogStatistics`, while spark's
stats are also persisted through `CatalogStatistics`. Therefore, in
`CatalogStatistics`, we cannot tell whether its stats is from hive or spark. As
a result, hive's stats can be unexpectedly propagated into spark' stats.
For example, by using "ALTER TABLE" command, we will store the stats info
(read from hive, e.g. "totalSize") in `CatalogStatistics` into metastore as
spark's stats (because we don't know whether it's from spark or not). But
spark's stats should be only generated by "ANALYZE" command. This is unexpected
from this command.
Besides, now that we store wrong spark's stats, after inserting new data,
although hive updated "totalSize" in metastore, we still cannot get the right
`sizeInBytes` in `CatalogStatistics`, because we respect the wrong spark stats
over hive's stats.
To fix this, we need to clearly separate spark's stats from hive's stats in
`CatalogStatistics`.
## How was this patch tested?
Modified existing tests and added a new test.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/wzhfy/spark separateHiveStats
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/18248.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 #18248
----
commit 0d56f165e4570f1b7a9908f4bceae55407e5cb03
Author: Zhenhua Wang <[email protected]>
Date: 2017-06-09T01:47:26Z
separation between spark's stats and hive's stats
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