[Rd] parse_Rd and/or lazyload problem

[Mark.Bravington at csiro.au]

Great-- thanks for the info.

For now, hopefully I can get the behaviour I want by sticking a .Call( 'R_lazyLoadDBflush'...) [as per 'detach'] before calling 'lazyLoad'. Seems to work on my examples, but please let me know if you don't think it'll work generally-- if not, I could presumably create the files under different names and then change them.

Is there merit in making 'makeLazyLoadDB' public, just as 'lazyLoad' already is? It's useful.

Mark

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Mark Bravington
CSIRO Mathematical & Information Sciences
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luke at stat.uiowa.edu wrote:
> Here is a more stripped down variant generates and error on OS X for
> me: 
> 
>      mkEg <- function(tm) list(scrunge = as.POSIXct(tm))
> 
>      extract <- function(db) {
>  	e<- new.env()
>  	lazyLoad(db, e)
>  	as.list( e)
>      }
> 
>      eg <- mkEg("2009-11-04 12:49:53")
>      eg1 <- mkEg("2009-11-04 12:49:28")
> 
>      tools:::makeLazyLoadDB( eg, '/tmp/ll')
>      extract('/tmp/ll') # force; OK
> 
>      tools:::makeLazyLoadDB( eg1, '/tmp/ll')
>      extract('/tmp/ll')
> 
> Changing the second set of /tmp/ll makes the symptom go away.
> 
> I believe this comes down to unintended use of the lazyload mechanism
> -- in particular it is not intended that a database be rewritten
> after it has been loaded.  There is a chaching mechanism for improved
> performance on slow file systems, and I believe what is happening is
> that the new indices are being used to look in the old chached data.
> There might be some merit in having lazyLoad call R_lazyLoadDBflush. 
> 
> luke
> 
> On Tue, 3 Nov 2009, Seth Falcon wrote:
> 
>> Hi,
>> 
>> On 11/3/09 6:51 PM, Mark.Bravington at csiro.au wrote:
>>> 
>>> file.copy( 'd:/temp/Rdiff.Rd', 'd:/temp/scrunge.Rd') # Rdiff.Rd
>>> from 'tools' package source 
>>> 
>>> eglist<- list( scrunge=parse_Rd(  'd:/temp/scrunge.Rd'))
>>> tools:::makeLazyLoadDB( eglist, 'd:/temp/ll')
>>> e<- new.env()
>>> lazyLoad( 'd:/temp/ll', e)
>>> as.list( e) # force; OK
>>> 
>>> eglist1<- list( scrunge=parse_Rd(  'd:/temp/Rdiff.Rd'))
>>> tools:::makeLazyLoadDB( eglist1, 'd:/temp/ll')
>>> e<- new.env()
>>> lazyLoad( 'd:/temp/ll', e)
>>> as.list( e) # Splat
>>> 
>>> It doesn't make any difference which file I process first; the error
>>> comes the second time round.
>> 
>> If I adjust this example in terms of paths and run on OS X, I get the
>> following error on the second run:
>> 
>>> as.list(e) # Splat
>> Error in as.list.environment(e) : internal error -3 in R_decompress1
>> 
>> I haven't looked further yet.
>> 
>> + seth
>> 
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