TPCDS queries #34, #73 doesn't work with block channels

[abyss7]

TPCDS queries #34, #73 doesn't work with block channels
Sample problem report: https://proxy.sandbox.yandex-team.ru/6854476973/index.html#suites/efe4970bacd9e1454955dc0317c12f5e/21b6d1b5165606bc/

Initially problem log looks like:

yql_provider_gateway.cpp:21: <main>: Fatal: ydb/library/yql/minikql/mkql_program_builder.cpp:5836: ScalarApply(): requirement !args.empty() failed. Required at least one argument, code: 1

I assume this expression causes problem, because the callable Nothing (which is NULL) has no arguments:

        (case when household_demographics.hd_vehicle_count > 0
	then household_demographics.hd_dep_count/ household_demographics.hd_vehicle_count
	else null
	end)

Intermediate AST looks like:

  (let $7 (Bool 'false))
  (let $8 (Member $5 '"hd_vehicle_count"))
  (let $9 (Coalesce (> $8 (Int32 '0)) $7))
  (let $10 (If $9 (/ (Member $5 '"hd_dep_count") $8) (Nothing (OptionalType (DataType 'Int64)))))

Full AST (at some point): https://paste.yandex-team.ru/285f7141-a0ea-4412-9aaf-197d50760a2d

[zverevgeny]

full ast https://gist.github.com/zverevgeny/06a7a86130537f1ac64b5e219d0f6552

[zverevgeny]

Null(Nothing) is not supported now in SsaProgram.
In this case it can be optimized out.
In general case, such push-downs must be blocked until Nothing is supported in SSA

[zverevgeny]

Rename title to the original one
The're several problems:

1. SsaProgram doesn't support passing Null in this case: Support NULLs in SSAProgram #7966
2. Optimizer pushes down unsupported predicates to CS: Do not pushdown NULLs to CS until they are supported #7967
3. In this case Nothing can be converted to False Swap if with comparator to get rid of nothing #8564