[gdal-dev] Memory usage for GetProjectionRef

[Livneh Yehiyam]

Hi
After further investigation I think the situation is more complex, as the results I'm getting depends on the file opened.
I ran the test with several tiff files and I'm getting completly different results, as described below.
Also, to rest my mind that this is not a problem with the C# binding, I'v created an identical test using the c interface.

case 1: 580MB tiff, tiled RGB with pyramid:
GDALOpen increased the memory by 17KB.
GetProjectionRef increased the memory by an additional 35KB.
After calling GDALClose, the memory was still 2KB more than before the call to GDALOpen.

case 1: 434MB tiff, tiled RGB without pyramid:
GDALOpen increased the memory by 40KB.
GetProjectionRef increased the memory by an additional 0.6KB.
After calling GDALClose, the memory was still 2KB more than before the call to GDALOpen.

case 3: 420MB tiff, one row per strip RGB without pyramid:
GDALOpen increased the memory by 186KB.
GetProjectionRef increased the memory by an additional 0.5KB.
After calling GDALClose, the memory was still 4KB more than before the call to GDALOpen.

case 4: 2GB tiff, one row per strip palette packbits compression without pyramid:
GDALOpen increased the memory by 867KB.
GetProjectionRef increased the memory by an additional 0.1KB.
After calling GDALClose, the memory was still 9KB more than before the call to GDALOpen.

Beside being very inconsistent (or at least I fail to see the pattern), a few things worry me, and might send me searching for another solution:
1. opening large stripped files increases the memory by almost 1MB. Multiplied by hundreds of files this amount to hundreds of MBs.
2. for a big tiled pyramid file, even the 35KB increase for just reading the projection might be too much.

-----Original Message-----
From: Chaitanya kumar CH [mailto:chaitanya.ch at gmail.com]
Sent: Tuesday, October 05, 2010 9:36 AM
To: Livneh Yehiyam
Cc: gdal-dev
Subject: Re: [gdal-dev] Memory usage for GetProjectionRef

Livneh,

I am assuming the 80KB refers to the memory change for getting the projection and not the whole dataset.
Can you check if the 80KB memory is freed and not leaked if the dataset is closed?

On Mon, Oct 4, 2010 at 10:41 PM, Livneh Yehiyam <yehil at rafael.co.il<mailto:yehil at rafael.co.il>> wrote:

Hi
We are using Gdal 1.7.0b from FWTools 2.7.1.
Our application is written in C#.
In our application we need to open a large number of tiff files (more than 2000).
We noticed that opening a dataset and then getting the projection string will increase the amount of memory (private bytes) by more that 80KB. This seems not a large amount, but multiplied by 2000 is more than 160MB.
Is anyone aware of such a problem?

Sent from my mobile

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