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duckplyr data frames

Source: R/ducktbl.R
duckdb_tibble.Rd

Data frames backed by duckplyr have a special class, "duckplyr_df", in addition to the default classes. This ensures that dplyr methods are dispatched correctly. For such objects, dplyr verbs such as dplyr::mutate(), dplyr::select() or dplyr::filter() will use DuckDB.

duckdb_tibble() works like tibble::tibble().

as_duckdb_tibble() converts a data frame or a dplyr lazy table to a duckplyr data frame. This is a generic function that can be overridden for custom classes.

is_duckdb_tibble() returns TRUE if x is a duckplyr data frame.

Usage

duckdb_tibble(..., .prudence = c("lavish", "thrifty", "stingy"))

as_duckdb_tibble(x, ..., prudence = c("lavish", "thrifty", "stingy"))

is_duckdb_tibble(x)

Arguments

...

For duckdb_tibble(), passed on to tibble::tibble(). For as_duckdb_tibble(), passed on to methods.

x

The object to convert or to test.

prudence, .prudence

Memory protection, controls if DuckDB may convert intermediate results in DuckDB-managed memory to data frames in R memory.

  • "lavish": regardless of size,

  • "stingy": never,

  • "thrifty": up to a maximum size of 1 million cells.

The default is "lavish" for duckdb_tibble() and as_duckdb_tibble(), and may be different for other functions. See vignette("prudence") for more information.

Value

For duckdb_tibble() and as_duckdb_tibble(), an object with the following classes:

  • "prudent_duckplyr_df" if prudence is not "lavish"

  • "duckplyr_df"

  • Classes of a tibble::tibble

For is_duckdb_tibble(), a scalar logical.

Fine-tuning prudence

[Experimental]

The prudence argument can also be a named numeric vector with at least one of cells or rows to limit the cells (values) and rows in the resulting data frame after automatic materialization. If both limits are specified, both are enforced. The equivalent of "thrifty" is c(cells = 1e6).

Examples

x <- duckdb_tibble(a = 1)
x
#> # A duckplyr data frame: 1 variable
#>       a
#>   <dbl>
#> 1     1

library(dplyr)
x %>%
  mutate(b = 2)
#> # A duckplyr data frame: 2 variables
#>       a     b
#>   <dbl> <dbl>
#> 1     1     2

x$a
#> [1] 1

y <- duckdb_tibble(a = 1, .prudence = "stingy")
y
#> # A duckplyr data frame: 1 variable
#>       a
#>   <dbl>
#> 1     1
try(length(y$a))
#> Error : Materialization is disabled, use collect() or as_tibble() to materialize.
length(collect(y)$a)
#> [1] 1