From: Niklas Holsti <niklas.holsti@nospam.please>
Subject: Re: Memory Useage
Date: Sat, 09 Jun 2007 08:25:54 +0300
Date: 2007-06-09T08:25:54+03:00 [thread overview]
Message-ID: <466a398f$0$8390$39db0f71@news.song.fi> (raw)
In-Reply-To: <1181335115.659050.135860@q69g2000hsb.googlegroups.com>
mhamel_98@yahoo.com wrote:
> Hello c.l.a. Another question, I have a program that stores data on
> the disk using sequential_io. When I later read that data into an
> array, the memory growth after ingesting a file is much much larger
> than the disk footprint. A file that takes 26.8MB on disk (over 134k
> records) causes the program to swell by over 600MB! Holy bloatware.
> A short overview of what I'm trying to do - each sequential_io data
> file has an associated header file with stuff like number of records,
> etc. The header is read, and an array is then created based on how
> many records are said to be in the data file. The data file is then
> read, sticking a node into the array. Some abbreviated code below,
> the spec:
>
> generic
> type Node_Type is private;
> package Node_Manager is
>
> package Seq is new Sequential_Io (Node_Type);
>
> type Node_Array is array (positive range <>) of Node_Type;
> type Node_Ptr is access Node_Array;
Is the actual type for Node_Type a record type with variants? If so, is
the size of the largest variant much larger than the size of the most
common variants? I don't know about ObjectAda, but in GNAT the
Node_Array would have a size that lets you store the largest variant in
every array element, while the Node_Type objects stored in the
sequential_io file probably use only as much file-space as the actual
variant of each object requires.
The solution in GNAT would be to allocate storage for each Node_Type
object separately and have an array of accesses:
type Node_Ptr is access Node_Type;
type Node_Array is array (positive range <>) of Node_Ptr;
type Node_Array_Ptr is access Node_Array;
This increases memory overhead by allocating more blocks from the heap,
but it may reduce the overall memory requirement if the largest variant
of Node_Type is much larger than the average variant.
--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
. @ .
next prev parent reply other threads:[~2007-06-09 5:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-08 20:38 Memory Useage mhamel_98
2007-06-09 0:43 ` Adam Beneschan
2007-06-09 3:09 ` mhamel_98
2007-06-09 5:25 ` Niklas Holsti [this message]
2007-06-11 15:28 ` mhamel_98
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