What is the initial (discovery) query when defining a datasource with the
My assumption is that the
tbl() is running a
SELECT * FROM <source_table> LIMIT <n> query in the background. Can you confirm?
I am asking because I run frequently in the
std::bad_alloc error, but the same query composed with
glue_sql() can be fetched without any error using the
dbGetQuery(). Some of unused columns triggers this error, but the custom made query is working ok because I am specifying the columns manually in the SQL query.
How many times is a query done for this piece of code (without the final
flights <- tbl(con, "flights") |> select(year:day, dep_delay, arr_delay) |> filter(dep_delay > 240)
(my guess is 2)
Do you have any idea how the columns can be specified with
tbl() in order to avoid this
std::bad_alloc type error (and still be able to use the flexibility of the
dplyr based queries)?