Steven Stillman <[email protected]> wrote:
>>This is more of a windows questions than a stata question. I frequently
>>work on large datasets (150-200m) on a Pent IIII PC w/ Win2000 and 512m ram.
>>I find that it takes a long time (3-5 minutes) for these large datasets to
>>initial open (stata is very fast once the datasets are loaded). Does anyone
>>have any suggestions on how to get Win2000 to allocate memory quicker to
>>stata (this seems to be what holds things up)? I was thinking that ala Unix
>>there might be a way to assign a fixed block of ram to stata instead of it
>>being dynamically reallocated every time a dataset is opened.
And Friedrich Huebler <[email protected]> had this suggestion:
>Do you use Stata 8 with a dataset from an earlier version of Stata?
>Try to convert the dataset to Stata 8 format and see if it takes less
>time to open.
This suggestion is a very good one. Using the latest format of dataset for your
version of Stata is always faster.
Another suggestion:
Due to the fact that it takes so long and that the size of the dataset is
already a large percentage of the physical RAM (200/512), the odds are that
Windows is being forced to use virtual memory. You can verify this by using the
Windows Task Manager (typically you can right-click on the task bar to bring up
the Task Manager; Ctrl-Alt-Del is another way to get to it). On the Task
Manager, there is a tab for Performance and on this tab is a couple of tables
showing memory usage. If your Total Commit Charge memory is higher than your
Total Physical memory, you are in a state where Windows is forced to use
virtual memory.
You can *probably* witness the problem by viewing the Available Physical Memory
_during_ the load of the Stata dataset -- it should hover around 6-3Mb as
Windows continually swaps memory from Physical to Virtual space.
Solutions:
1. Buy more RAM.
2. Close all unnecessary applications while you are working with these
large datasets.
3. There are a few more odd tricks that can be done to speed up
virtual memory, but may not fix the entire problem:
http://www.pureperformance.com/js/showtip.asp?id=22
Hope this helps,
--Kevin
[email protected]
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