[SPARK-30262][SQL] Avoid NumberFormatException when totalSize is empty

[southernriver]

What changes were proposed in this pull request?

We could get the Partitions Statistics Info.But in some specail case, The Info like totalSize，rawDataSize，rowCount maybe empty. When we do some ddls like
desc formatted partition ,the NumberFormatException is showed as below:

spark-sql> desc formatted table1 partition(year='2019', month='10', day='17', hour='23');
19/10/19 00:02:40 ERROR SparkSQLDriver: Failed in [desc formatted table1 partition(year='2019', month='10', day='17', hour='23')]
java.lang.NumberFormatException: Zero length BigInteger
at java.math.BigInteger.(BigInteger.java:411)
at java.math.BigInteger.(BigInteger.java:597)
at scala.math.BigInt$.apply(BigInt.scala:77)
at org.apache.spark.sql.hive.client.HiveClientImpl$$anonfun$31.apply(HiveClientImpl.scala:1056)

Although we can use 'Analyze table partition ' to update the totalSize,rawDataSize or rowCount, it's unresonable for normal SQL to throw NumberFormatException for Empty totalSize.We should fix the empty case when readHiveStats.

Why are the changes needed?

This is a related to the robustness of the code and may lead to unexpected exception in some unpredictable situation.Here is the case:

Does this PR introduce any user-facing change?

No

How was this patch tested?

manual

[dongjoon-hyun]

Thank you for your first contribution, @southernriver .

[dongjoon-hyun]

ok to test

[SparkQA]

Test build #115338 has finished for PR 26892 at commit aff4a33.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[dongjoon-hyun]

This is a logical patch, but there is no evidence when this happens.
Could you give me a reproducible procedure which you met?

[dongjoon-hyun]

I'm wondering if you are hitting the other system's bug. Then, you had better fix the root cause.

This is a related to the robustness of the code and may lead to unexpected exception in some unpredictable situation.Here is the case:

[maropu]

Also, can you add tests for that?

[dongjoon-hyun]

Okay. Since this is a trivial safeguard, I'll merge this to master. Thank you, @southernriver , @srowen , @maropu .

[dongjoon-hyun]

@southernriver . You are added to the Apache Spark contributor group and SPARK-30262 is assigned to you. Thank you again.