read_only flag in dbConnect doesn't appear to be working

[JordanMPDS]

While trying to setup a shiny app I started playing around with the read_only option in dbConnect() as listed in R Client. It doesn't appear that this option is working.

I load my packages and connect to the db

> # Loading required packages
> library(DBI)
> library(duckdb)
> library(dplyr)
> library(glue)
>
> # Creating connection
> con <- dbConnect(duckdb(),
+                  dbdir = "C:\\Users\\Jordan\\Documents\\r-stuff\\home.duckdb$
+                  read_only = TRUE)

Next I do a quick SQL statement to check my access mode

> dbGetQuery(con, "SELECT current_setting('access_mode')")
  current_setting('access_mode')
1                      automatic

I have read_only flagged as true in my connection, but when i query my access mode it doesn't say read only. Any reason this would be happening?

Here is my session info.

> sessionInfo()
R version 4.4.1 (2024-06-14 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 10 x64 (build 19045)

Matrix products: default


locale:
[1] LC_COLLATE=English_United States.utf8 
[2] LC_CTYPE=English_United States.utf8   
[3] LC_MONETARY=English_United States.utf8
[4] LC_NUMERIC=C        
[5] LC_TIME=English_United States.utf8    

time zone: America/Chicago
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] glue_1.8.0   dplyr_1.1.4  duckdb_1.2.0 DBI_1.2.3

loaded via a namespace (and not attached):
 [1] R6_2.5.1         tidyselect_1.2.1 magrittr_2.0.3   tibble_3.2.1
 [5] pkgconfig_2.0.3  generics_0.1.3   lifecycle_1.0.4  cli_3.6.3
 [9] vctrs_0.6.5      compiler_4.4.1   tools_4.4.1      pillar_1.10.1
[13] rlang_1.1.4      jsonlite_1.8.9

[krlmlr]

Thanks. This is not what I see. Do you need to create the database file first?

options(conflicts.policy = list(warn = FALSE))
library(duckdb)
#> Loading required package: DBI

con <- dbConnect(duckdb(), "test.duckdb")
dbDisconnect(con)

con <- dbConnect(duckdb(), "test.duckdb", read_only = TRUE)
dbGetQuery(con, "SELECT current_setting('access_mode')")
#>   current_setting('access_mode')
#> 1                      read_only
dbDisconnect(con)

con <- dbConnect(duckdb(dbdir = "test.duckdb", read_only = TRUE))
dbGetQuery(con, "SELECT current_setting('access_mode')")
#>   current_setting('access_mode')
#> 1                      read_only
dbDisconnect(con)

^{Created on 2025-04-28 with reprex v2.1.1}

[JordanMPDS]

Thanks. This is not what I see. Do you need to create the database file first?

options(conflicts.policy = list(warn = FALSE))
library(duckdb)
#> Loading required package: DBI

con <- dbConnect(duckdb(), "test.duckdb")
dbDisconnect(con)

con <- dbConnect(duckdb(), "test.duckdb", read_only = TRUE)
dbGetQuery(con, "SELECT current_setting('access_mode')")
#> current_setting('access_mode')
#> 1 read_only
dbDisconnect(con)

con <- dbConnect(duckdb(dbdir = "test.duckdb", read_only = TRUE))
dbGetQuery(con, "SELECT current_setting('access_mode')")
#> current_setting('access_mode')
#> 1 read_only
dbDisconnect(con)

Created on 2025-04-28 with reprex v2.1.1

The database was already created at this point. I also see your dbConnect string is different than what I used.