[SPARK-12904][SQL] Strength reduction for integral/decimal comparisons

[viirya]

JIRA: https://issues.apache.org/jira/browse/SPARK-12904

We can do the following strength reduction for comparisons between an integral column and a decimal literal:

1. int_col > decimal_literal => int_col > floor(decimal_literal)
2. int_col >= decimal_literal => int_col >= ceil(decimal_literal)
3. int_col < decimal_literal => int_col < ceil(decimal_literal)
4. int_col <= decimal_literal => int_col <= floor(decimal_literal)
5. decimal_literal > int_col => ceil(decimal_literal) > int_col
6. decimal_literal >= int_col => floor(decimal_literal) >= int_col
7. decimal_literal < int_col => floor(decimal_literal) < int_col
8. decimal_literal <= int_col => ceil(decimal_literal) <= int_col

[viirya]

We add this rule in analyser instead of optimizer because DecimalPrecision and ImplicitTypeCasts rules in analyser will add additional Cast operator to the integer expression.

[SparkQA]

Test build #49772 has finished for PR 10845 at commit 5a96018.

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

[SparkQA]

Test build #49863 has finished for PR 10845 at commit 7202c54.

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

[rxin]

this should apply for any integral type, not just integer. Also can you make this function shorter by breaking it into two functions? It is pretty long now.

[SparkQA]

Test build #49902 has finished for PR 10845 at commit a1271fe.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #49906 has finished for PR 10845 at commit 1de0616.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[viirya]

retest this please.

[rxin]

i don't think you can just do a toInt here .... decimal scope is larger than int.

[rxin]

@viirya rather than me pointing out all the problem in each iteration, can you try figuring out all the corner cases yourself and then submit this for review? Thanks.

[SparkQA]

Test build #49915 has finished for PR 10845 at commit 1de0616.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[viirya]

@rxin Sure.

[SparkQA]

Test build #49918 has finished for PR 10845 at commit dc05a08.

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