Tables with date columns designated as Nullable() prompt error upon appending

[JSchoenbachler]

When using DBI::dbWriteTable() where append=TRUE and inserting into a table that has date columns that are designated as Nullable(), the following error prompts every time:

Error in insert(conn@ptr, qname, value) : 
  count of elements in nested and nulls should be the same

I created 2 tables for examples by doing the following:

create table clicktest.testTable1 (`a` Nullable(String), `b` Nullable(UInt32), `c` Nullable(Date)) ENGINE=MergeTree() ORDER BY tuple()
create table clicktest.testTable2 (`a` Nullable(String), `b` Nullable(UInt32), `c` Date) ENGINE=MergeTree() ORDER BY tuple()

Which just created 2 identical tables, other than the date column being nullable on testTable1 and not testTable2. When using RClickhouse to insert the following row:

dt = data.table(a = 'abc', b = 1, c = as.Date('2000-01-01'))
DBI::dbWriteTable(con, 'testTable1', dt, append = TRUE, overwrite = FALSE)
DBI::dbWriteTable(con, 'testTable2', dt, append = TRUE, overwrite = FALSE)

The first statement will produce the error above, meanwhile the second will insert into the table with no issues.

[JSchoenbachler]

I forgot to mention, I experienced similar behavior when doing the same with Nullable DateTime columns.

[tridelt]

Hi @JSchoenbachler
I am still doing some testing, but I believe to have found the reason. The NullablePtr that is pointing to the enclosing Nullable Container of the Date-Column wasn't passed to the function that turns R columns into C++ columns. Hopefully this fixes it for you.
Best regards
tridelt

[zylsun]

c2952bf did not fix the same error for datetime.

I forgot to mention, I experienced similar behavior when doing the same with Nullable DateTime columns.

[tridelt]

@zylsun Thank you for the heads up. I will try to reproduce it and see if a similar fix is applicable there also.