Fix executing empty sql statement in preactions and postactions

[meetchandan]

Say for example:
you need to execute preactions/postactions

val preactions = "update table1 set col1=2; update table2 set col2 = 2; "
Looks nothing wrong, correct?

Only when you try to execute it, you will get weird error:

Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: 0

This is because of Line 248 and Line 260 in Parameters.scala
def preActions: Array[String] = parameters("preactions").split(";")

def postActions: Array[String] = parameters("postactions").split(";")

the above functions are called in RedshiftWriter.scala LN: 132 and LN: 195
parameters("preactions").split(";")
-- this returns an array of 3 items, with the 3rd item being empty string (only spaces) - see trailing spaces in
val preactions = "update table1 set col1=2; update table2 set col2 = 2; "

and then it tries to execute sql query which is essentially just "spaces"

The fix is to just trim preactions and postactions so that the trailing spaces are not considered as query to be executed

[meetchandan]

I am working on the fix and will soon raise a PR

[meetchandan]

Link to PR:
#440

[meetchandan]

@JoshRosen @marmbrus @brkyvz Please take a look

[aleksandr-bogdanov]

Having the same issue, your fix would help a lot.

[meetchandan]

can we merge this please @JoshRosen