[GitHub] [arrow-adbc] paleolimbot commented on pull request #985: feat(r): Add async infrastructure for specific methods

["paleolimbot (via GitHub)" <gi...@apache.org>]

paleolimbot commented on PR #985:
URL: https://github.com/apache/arrow-adbc/pull/985#issuecomment-1706960502

   Far from usable, but it works! Probably needs some version of "read everything from `stream` with a callback for each batch...I'm not sure that fits nicely into `promises` since there are an indeterminate number of batches.
   
   ``` r
   library(adbcdrivermanager)
   
   db <- adbc_database_init(adbcsqlite::adbcsqlite())
   con <- adbc_connection_init(db)
   
   flights <- nycflights13::flights
   flights$time_hour <- NULL
   flights |>
     write_adbc(con, "flights")
   
   
   # Sync
   stmt <- adbc_statement_init(con)
   adbc_statement_set_sql_query(stmt, "SELECT * from flights")
   stream <- nanoarrow::nanoarrow_allocate_array_stream()
   adbc_statement_execute_query(stmt, stream)
   #> [1] -1
   stream
   #> <nanoarrow_array_stream struct<year: int64, month: int64, day: int64, dep_time: int64, sched_dep_time: int64, dep_delay: double, arr_time: int64, sched_arr_time: int64, arr_delay: double, carrier: string, flight: int64, tailnum: string, origin: string, dest: string, air_time: double, distance: double, hour: double, minute: double>>
   #>  $ get_schema:function ()  
   #>  $ get_next  :function (schema = x$get_schema(), validate = TRUE)  
   #>  $ release   :function ()
   
   value <- NULL
   
   
   # Async
   (promise <- con |> 
     adbc_statement_init() |> 
     adbc_statement_set_sql_query("SELECT * from flights") |> 
     adbcdrivermanager:::adbc_statement_execute_query_promise() |> 
     promises::then(function(stream) {
       adbcdrivermanager:::adbc_array_stream_get_next_promise(stream)
     }) |> 
     promises::then(function(array) {
       tibble::as_tibble(array)
     }) |> 
     promises::then(function(tbl) {
       value <<- tbl
     }))
   #> <Promise [pending]>
   
   value
   #> NULL
   
   while(!later::loop_empty()) {
     later::run_now()
   }
   
   promise
   #> <Promise [fulfilled: tbl_df]>
   value
   #> # A tibble: 1,024 × 18
   #>     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
   #>    <dbl> <dbl> <dbl>    <dbl>          <dbl>     <dbl>    <dbl>          <dbl>
   #>  1  2013     1     1      517            515         2      830            819
   #>  2  2013     1     1      533            529         4      850            830
   #>  3  2013     1     1      542            540         2      923            850
   #>  4  2013     1     1      544            545        -1     1004           1022
   #>  5  2013     1     1      554            600        -6      812            837
   #>  6  2013     1     1      554            558        -4      740            728
   #>  7  2013     1     1      555            600        -5      913            854
   #>  8  2013     1     1      557            600        -3      709            723
   #>  9  2013     1     1      557            600        -3      838            846
   #> 10  2013     1     1      558            600        -2      753            745
   #> # ℹ 1,014 more rows
   #> # ℹ 10 more variables: arr_delay <dbl>, carrier <chr>, flight <dbl>,
   #> #   tailnum <chr>, origin <chr>, dest <chr>, air_time <dbl>, distance <dbl>,
   #> #   hour <dbl>, minute <dbl>
   ```
   
   <sup>Created on 2023-09-05 with [reprex v2.0.2](https://reprex.tidyverse.org)</sup>


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