断开dplyr中的src_tbls连接

Question

有没有办法强制断开一个类似的src_tbls对象？dplyrRPostgreSQL::dbDisconnect

参见例如:

> 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)

作为旁注,几秒后它会很快自动断开:

Auto-disconnecting postgres connection (3734, 26)

之后您可以src_postgres再次运行该命令.

Answer 1

你可以做:

RPostgreSQL::dbDisconnect(src_temp$con)

迫使断开连接.

这就是dplyr(通过dbi-s3.r源文件)从此函数调用垃圾回收的原因:

# 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()
}