Re: [boost] Random Access to Files (RAF) - any interest ?

From: Slava, Alex (raf.devel_at_[hidden])
Date: 2006-05-20 03:57:33

On 5/19/06, Xi Wang <xi.wang_at_[hidden]> wrote:
>  Nice:-) I'd like to see more methods such as push_back, though resize
> could make it but not so convenient. And are there any plans for supporting
> insert/erase a record or a range of records?
>
resize routine is very expensive, thus it should be invoked as rare as posible.
push_back() makes resize each time called, so it is not effective.

insert/erase question: what to do with the tail of the file in this cases?

> Here are some more timings, FYI. All tests were performed on WinXP SP2
> with P4 3GHz HT, 1G memory, using test.cpp compiled by VC8 (cl /O2 /EHsc).
> Sequential tests read/write on a file sized 40M, while random tests were
> also
> limited to 1,000,000 iterations.
>
> Test type         stub cstdio fstream randfile
> ----------------------------------------------
> Sequential read   0.03   6.87   23.76     0.05
> Sequential write  1.70  10.09   11.61     1.97
> Random read       0.03   4.31    9.58     0.05
> Random write      0.09   7.42   13.56     0.09
> Random read/write 0.14   6.95   13.34     0.14
>
> ps: cstdio and fstream implementations are those shipped with VC8.

Thank you very much for performance testing.

-- 
Svyatoslav Trukhanov,
Oleksii Ursulenko