From 4873c84975d3a01a6325c57c62f951e6c0a0464a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Sun, 12 Sep 2021 17:37:41 +0200
Subject: [PATCH] copy = NULL default for dbWriteTable() and dbAppendTable()

---
 R/tables.R             | 10 ++++++++--
 man/postgres-tables.Rd |  8 +++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/R/tables.R b/R/tables.R
index 5e0d3ac3..7352c35f 100644
--- a/R/tables.R
+++ b/R/tables.R
@@ -24,6 +24,8 @@
 #'   and uses `COPY name FROM stdin`. This is fast, but not supported by
 #'   all postgres servers (e.g. Amazon's Redshift). If `FALSE`, generates
 #'   a single SQL string. This is slower, but always supported.
+#'   The default maps to `TRUE` on connections established via [Postgres()]
+#'   and to `FALSE` on connections established via [Redshift()].
 #'
 #' @examplesIf postgresHasDefault()
 #' library(DBI)
@@ -47,7 +49,7 @@ NULL
 #' @rdname postgres-tables
 setMethod("dbWriteTable", c("PqConnection", "character", "data.frame"),
   function(conn, name, value, ..., row.names = FALSE, overwrite = FALSE, append = FALSE,
-           field.types = NULL, temporary = FALSE, copy = TRUE) {
+           field.types = NULL, temporary = FALSE, copy = NULL) {
 
     if (is.null(row.names)) row.names <- FALSE
     if ((!is.logical(row.names) && !is.character(row.names)) || length(row.names) != 1L)  {
@@ -181,7 +183,7 @@ format_keep_na <- function(x, ...) {
 #' @rdname postgres-tables
 #' @export
 setMethod("dbAppendTable", c("PqConnection"),
-  function(conn, name, value, copy = TRUE, ..., row.names = NULL) {
+  function(conn, name, value, copy = NULL, ..., row.names = NULL) {
     stopifnot(is.null(row.names))
     stopifnot(is.data.frame(value))
     db_append_table(conn, name, value, copy = copy, warn = TRUE)
@@ -191,6 +193,10 @@ setMethod("dbAppendTable", c("PqConnection"),
 db_append_table <- function(conn, name, value, copy, warn) {
   value <- factor_to_string(value, warn = warn)
 
+  if (is.null(copy)) {
+    copy <- !is(conn, "RedshiftConnection")
+  }
+
   if (copy) {
     value <- sql_data_copy(value, row.names = FALSE)
 
diff --git a/man/postgres-tables.Rd b/man/postgres-tables.Rd
index 1fd96999..6a374199 100644
--- a/man/postgres-tables.Rd
+++ b/man/postgres-tables.Rd
@@ -25,12 +25,12 @@
   append = FALSE,
   field.types = NULL,
   temporary = FALSE,
-  copy = TRUE
+  copy = NULL
 )
 
 \S4method{sqlData}{PqConnection}(con, value, row.names = FALSE, ...)
 
-\S4method{dbAppendTable}{PqConnection}(conn, name, value, copy = TRUE, ..., row.names = NULL)
+\S4method{dbAppendTable}{PqConnection}(conn, name, value, copy = NULL, ..., row.names = NULL)
 
 \S4method{dbReadTable}{PqConnection,character}(conn, name, ..., check.names = TRUE, row.names = FALSE)
 
@@ -86,7 +86,9 @@ with \code{\link[DBI:dbDataType]{DBI::dbDataType()}}).}
 \item{copy}{If \code{TRUE}, serializes the data frame to a single string
 and uses \verb{COPY name FROM stdin}. This is fast, but not supported by
 all postgres servers (e.g. Amazon's Redshift). If \code{FALSE}, generates
-a single SQL string. This is slower, but always supported.}
+a single SQL string. This is slower, but always supported.
+The default maps to \code{TRUE} on connections established via \code{\link[=Postgres]{Postgres()}}
+and to \code{FALSE} on connections established via \code{\link[=Redshift]{Redshift()}}.}
 
 \item{con}{A database connection.}