Thanks for the input gents. I’m going to have to look into the memory stuff as
it’s something I know little about and it’s near bedtime in Scotland.
Warren, the actual programme does use the vector (it’s used to store the
RowIDs). The console app mark 1 also did this (results were the same) bu
On May 26, 2018, at 9:43 AM, x wrote:
>
> I was sizing the vector beforehand and then timing how long it took to store
> the RowIDs returned by an sqlite query.
You’re not actually modifying the vector, only allocating it and then not using
it. A sufficiently smart optimizer might optimize tha
Collect some memory statistics before and after memory allocation and
before and after query execution.
#include
#include
#include
void memoryStats()
{
PROCESS_MEMORY_COUNTERS_EX pmc;
PERFORMANCE_INFORMATION pi;
MEMORYSTATUSEX ms;
Ze
x wrote:
> const int Size[]={11200,10}; // 112 million, 1 billion
>
> v.resize(Size[i]);
>
> // NB the exact same code is executed whether i is 0 or 1.
> The only thing that
> // changes is the size() of v and v isn't even used in the
>
I also added v.shrink_to_fit() after the resize and tried again with Size[0]
and Size[1] swapped. The time difference reappeared with the second pass 4+
secs faster than the first.
From: sqlite-users on behalf of
Abroży Nieprzełoży
Sent: Saturday, May 26, 20
Hi Abrozy.
I inserted the line
int64_t Mem=sqlite3_memory_highwater(0);
immediately after the while loop and added Mem to the cout. The values returned
were
2234704 (I==0)
2234768 (I==1).
Tom
From: sqlite-users on behalf of
Abroży Nieprzełoży
> I swapped Size[0] with Size[1] so that the resize was going from large to
> small. The timings on each pass were then similar but were still around the
> 24.xxx mark associated with the i==1 pass.
Note the difference between size and capacity of the vector.
Reducing the size does not necessarily
I'm using c++ builder 10.2 tokyo on windows 10 and sqlite 3.23.1. I was working
on code that stored RowIDs in a vector. I was sizing the vector beforehand and
then timing how long it took to store the RowIDs returned by an sqlite query.
By accident I sized the vector too big (by a factor of 10)
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