Document behavior

R/Driver.R

@@ -31,25 +31,27 @@ duckdb <- function(dbdir = DBDIR_MEMORY, read_only = FALSE, bigint = "numeric",
   check_flag(read_only)
   check_bigint(bigint)
 
-  # R packages are not allowed to write extensions into home directory, so use R_user_dir instead
-  if (!("extension_directory" %in% names(config))) {
-    config["extension_directory"] <- file.path(tools::R_user_dir("duckdb", "data"), "extensions")
-  }
-  if (!("secret_directory" %in% names(config))) {
-    config["secret_directory"] <- file.path(tools::R_user_dir("duckdb", "data"), "stored_secrets")
-  }
-
   dbdir <- path_normalize(dbdir)
   if (dbdir != DBDIR_MEMORY) {
     drv <- driver_registry[[dbdir]]
     # We reuse an existing driver object if the database is still alive.
     # If not, we fall back to creating a new driver object with a new database.
     if (!is.null(drv) && rapi_lock(drv@database_ref)) {
-      # FIXME: Check that readonly and config are identical
+      # We don't care about different read_only or config settings here.
+      # The bigint setting can be actually picked up by dbConnect(), we update it here.
+      drv@bigint <- bigint
       return(drv)
     }
   }
 
+  # R packages are not allowed to write extensions into home directory, so use R_user_dir instead
+  if (!("extension_directory" %in% names(config))) {
+    config["extension_directory"] <- file.path(tools::R_user_dir("duckdb", "data"), "extensions")
+  }
+  if (!("secret_directory" %in% names(config))) {
+    config["secret_directory"] <- file.path(tools::R_user_dir("duckdb", "data"), "stored_secrets")
+  }
+
   # Always create new database for in-memory,
   # allows isolation and mixing different configs
   drv <- new(

R/dbConnect__duckdb_driver.R

@@ -8,7 +8,10 @@
 #'   data is kept in RAM.
 #' @param ... Ignored
 #' @param debug Print additional debug information such as queries
-#' @param read_only Set to `TRUE` for read-only operation
+#' @param read_only Set to `TRUE` for read-only operation.
+#'   For file-based databases, this is only applied when the database file is opened for the first time.
+#'   Subsequent connections (via the same `drv` object or a `drv` object pointing to the same path)
+#'   will silently ignore this flag.
 #' @param timezone_out The time zone returned to R, defaults to `"UTC"`, which
 #'   is currently the only timezone supported by duckdb.
 #'   If you want to display datetime values in the local timezone,
@@ -18,7 +21,10 @@
 #'   is chosen, the timestamp will be returned as it would appear in the specified time zone.
 #'   If `"force"` is chosen, the timestamp will have the same clock
 #'   time as the timestamp in the database, but with the new time zone.
-#' @param config Named list with DuckDB configuration flags
+#' @param config Named list with DuckDB configuration flags, see
+#'   <https://duckdb.org/docs/configuration/overview#configuration-reference> for the possible options.
+#'   These flags are only applied when the database object is instantiated.
+#'   Subsequent connections will silently ignore these flags.
 #' @param bigint How 64-bit integers should be returned. There are two options: `"numeric"` and `"integer64"`.
 #'   If `"numeric"` is selected, bigint integers will be treated as double/numeric.
 #'   If `"integer64"` is selected, bigint integers will be set to bit64 encoding.