sql - 断开 dplyr 中的 src_tbls 连接

Question

有没有办法强制断开dplyr中的src_tbls对象，类似于RPostgreSQL::dbDisconnect？

参见示例:

> src_temp <- src_postgres(dbname = "temp", host = "127.0.0.1", port = 5432, user = "x", password = "y")
Error in postgresqlNewConnection(drv, ...) : 
  RS-DBI driver: (cannot allocate a new connection -- maximum of 16 connections already opened)

顺便说一句，它会在几秒钟后很快自动断开连接:

Auto-disconnecting postgres connection (3734, 26)

之后您可以再次运行src_postgres命令。

Answer 1

你可以这样做:

RPostgreSQL::dbDisconnect(src_temp$con)

强制断开连接。

这就是 dplyr 中此函数调用垃圾收集的内容(通过 dbi-s3.r 源文件):

# Creates an environment that disconnects the database when it's
# garbage collected
db_disconnector <- function(con, name, quiet = FALSE) {
  reg.finalizer(environment(), function(...) {
    if (!quiet) {
      message("Auto-disconnecting ", name, " connection ",
        "(", paste(con@Id, collapse = ", "), ")")
    }
    dbDisconnect(con)
  })
  environment()
}