RPostgreSQL driver timestamp data type mapping

On Wed, 13 Jan 2010 07:09:57 +0000 (GMT),

[...]

Not really: POSIXct times are absolute times: it is when they are
displayed that you see the locale.  So just add a tzone attribute to
the result, as in

x <- Sys.time()
x

[1] "2010-01-13 07:07:26 GMT"

attr(x, "tzone") <- "PST8DST"
x

[1] "2010-01-12 23:07:26 PST"

attr(x, "tzone") <- NULL
x

[1] "2010-01-13 07:07:26 GMT"

Does setting tzone=NULL have the same effect as setting it to "GMT", in
that daylight savings are no longer relevant?  This is the only reason I
wanted to set it "GMT", and avoid daylight savings issues that I don't
need to deal with.  Usually I do this starting from a character vector,
as in:

as.POSIXct(strptime("2010-01-13 01:00:00", "%Y-%m-%d %H:%M:%S), tz="GMT")

Thanks,

Seb