WIP: demo for relational API

[krlmlr]

Needs https://github.com/duckdb/duckdb and https://github.com/duckdblabs/relational.

CC @hannes.

library(tidyverse)

options(duckdb.materialize_message = TRUE)

df <- palmerpenguins::penguins

# No materialization should happen here!
out <-
  df %>%
  slice_head(n = 10)

# Materializing should happen only here!
out
#> [1] TRUE
#> materializing:
#> ---------------------
#> --- Relation Tree ---
#> ---------------------
#> Limit 10
#>   r_dataframe_scan(0x108df73c8)
#> 
#> ---------------------
#> -- Result Columns  --
#> ---------------------
#> - species (species)
#> - island (island)
#> - bill_length_mm (DOUBLE)
#> - bill_depth_mm (DOUBLE)
#> - flipper_length_mm (INTEGER)
#> - body_mass_g (INTEGER)
#> - sex (sex)
#> - year (INTEGER)
#> 
#> # A tibble: 10 × 8
#>    species island    bill_length_mm bill_depth_mm flipper_…¹ body_…² sex    year
#>    <fct>   <fct>              <dbl>         <dbl>      <int>   <int> <fct> <int>
#>  1 Adelie  Torgersen           39.1          18.7        181    3750 male   2007
#>  2 Adelie  Torgersen           39.5          17.4        186    3800 fema…  2007
#>  3 Adelie  Torgersen           40.3          18          195    3250 fema…  2007
#>  4 Adelie  Torgersen           NA            NA           NA      NA <NA>   2007
#>  5 Adelie  Torgersen           36.7          19.3        193    3450 fema…  2007
#>  6 Adelie  Torgersen           39.3          20.6        190    3650 male   2007
#>  7 Adelie  Torgersen           38.9          17.8        181    3625 fema…  2007
#>  8 Adelie  Torgersen           39.2          19.6        195    4675 male   2007
#>  9 Adelie  Torgersen           34.1          18.1        193    3475 <NA>   2007
#> 10 Adelie  Torgersen           42            20.2        190    4250 <NA>   2007
#> # … with abbreviated variable names ¹​flipper_length_mm, ²​body_mass_g

^{Created on 2022-11-12 with reprex v2.0.2}

[krlmlr]

Now, with most recent code and main branch from duckdb:

# pkgload::load_all()
# pkgload::load_all("../relational")
# pkgload::load_all("../duckdb/tools/rpkg")
library(tidyverse)

df <- palmerpenguins::penguins

# No materialization should happen here!
out <-
  df %>%
  transmute(bill_area = bill_length_mm * bill_depth_mm, bill_length_mm, species, sex) %>%
  filter(bill_length_mm < 40) %>%
  select(-bill_length_mm) %>%
  slice_head(n = 5)

out %>%
  explain()
#> ┌───────────────────────────┐
#> │      STREAMING_LIMIT      │
#> └─────────────┬─────────────┘                             
#> ┌─────────────┴─────────────┐
#> │         PROJECTION        │
#> │   ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─   │
#> │         bill_area         │
#> │          species          │
#> │            sex            │
#> └─────────────┬─────────────┘                             
#> ┌─────────────┴─────────────┐
#> │           FILTER          │
#> │   ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─   │
#> │  (bill_length_mm < 40.0)  │
#> └─────────────┬─────────────┘                             
#> ┌─────────────┴─────────────┐
#> │      R_DATAFRAME_SCAN     │
#> │   ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─   │
#> │         data.frame        │
#> │   ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─   │
#> │           EC=344          │
#> └───────────────────────────┘

# Materializing should happen only here!
out
#> materializing:
#> ---------------------
#> --- Relation Tree ---
#> ---------------------
#> Limit 5
#>   Projection [bill_area as bill_area, species as species, sex as sex]
#>     Filter [<(bill_length_mm, 40.0)]
#>       Projection [*(bill_length_mm, bill_depth_mm) as bill_area, bill_length_mm as bill_length_mm, species as species, sex as sex]
#>         r_dataframe_scan(0x124e754b8)
#> 
#> ---------------------
#> -- Result Columns  --
#> ---------------------
#> - bill_area (DOUBLE)
#> - species (species)
#> - sex (sex)
#> 
#> # A tibble: 5 × 3
#>   bill_area species sex   
#>       <dbl> <fct>   <fct> 
#> 1      731. Adelie  male  
#> 2      687. Adelie  female
#> 3      708. Adelie  female
#> 4      810. Adelie  male  
#> 5      692. Adelie  female

^{Created on 2022-11-24 with reprex v2.0.2}