Re: [Boost-users] Interprocess : vectors of vectors

Subject: Re: [Boost-users] Interprocess : vectors of vectors
From: Oodini (svdbg____at_[hidden])
Date: 2013-05-16 07:25:09

> If you have plenty of memory (especially virtual memory), then just
> make it huge, and don't worry about using it all.

Actualy, my data will take about 26 Gb...
Tha's why I want to control the memory.

> there might be a bit of extra bookkeeping in the
> vector "header" itself.

That's one of the problem.

> a. vectors tend to allocate extra space (think "reserve()" and
>    "capacity()" vs. "resize()" and "size()").

reserve(1) or reserve(5) take the same amount of memory.

> b. chunks of memory are often larger than actually requested (to
>    improve performance, or to stash housekeeping information with
>    each chunk).

Yes. I'd like to control this behaviour.

> So whatever value you get for "total_memory", remember that you need
> to increase it by some amount.

As we are supposed to provide an exact value for the shared memory, there should be a way to know exactly how much memory consume the data structures.

> If you have the memory to spare, go
> for double, and you should be fine; if you're tight, try maybe 20%
> more, and pay extra attention to your exception paths.

I can't...
Thanks a lot for your contribution.

I switck back on an implementation based on pointers instead of vectors.