2009/8/9 Jorge Arévalo jorge.arev...@gmail.com:
Then, my point could be, when creating the dataset (Open static
method), perform a query to get all the blocks that cover the extent
of the raster (the extent is in RASTER_COLUMNS table) and store them
in any place (A new class attribute?, flush
Frank Warmerdam wrote:
2009/8/9 Jorge Arévalo jorge.arev...@gmail.com:
Then, my point could be, when creating the dataset (Open static
method), perform a query to get all the blocks that cover the
extent of the raster (the extent is in RASTER_COLUMNS table) and
store them in any place (A new
Hello,
2009/8/12 Mateusz Loskot mate...@loskot.net:
Frank Warmerdam wrote:
2009/8/9 Jorge Arévalo jorge.arev...@gmail.com:
Then, my point could be, when creating the dataset (Open static
method), perform a query to get all the blocks that cover the
extent of the raster (the extent is in
Jorge Arévalo wrote:
Hello,
2009/8/12 Mateusz Loskot mate...@loskot.net:
Frank Warmerdam wrote:
2009/8/9 Jorge Arévalo jorge.arev...@gmail.com:
Then, my point could be, when creating the dataset (Open static
method), perform a query to get all the blocks that cover the
extent of the
2009/8/12 Jorge Arévalo jorge.arev...@gmail.com
I'm afraid I have not quite followed the discussion of the IRasterIO
implementation, but I find the above statement quite alarming. It is
imperative that we *not* end up reading back all blocks if only a few
are requested. Imagine a 100GB
Hello,
2009/8/12 Tamas Szekeres szeker...@gmail.com:
2009/8/12 Jorge Arévalo jorge.arev...@gmail.com
I'm afraid I have not quite followed the discussion of the IRasterIO
implementation, but I find the above statement quite alarming. It is
imperative that we *not* end up reading back all
2009/8/7 Even Rouault even.roua...@mines-paris.org:
- Original Message - From: Jorge Arévalo jorge.arev...@gmail.com
To: Tamas Szekeres szeker...@gmail.com
Cc: gdal-dev gdal-dev@lists.osgeo.org
Sent: Friday, August 07, 2009 7:43 PM
Subject: Re: [gdal-dev] Overriding IRasterIO
Hello Tamas,
2009/8/8 Tamas Szekeres szeker...@gmail.com:
Hi Jorge,
What I have in my mind is something like the DirectRasterIO implementation
in WCSDataset / WCSRasterBand (see wcsdataset.cpp). It appears that this
driver is suffering from the same issue, and intend to minimize the
Hello,
2009/8/7 Tamas Szekeres szeker...@gmail.com:
Just thinking out loadly;
Wouldn't it be easier to implement that cache at the driver level, just by
composing the raster in a temp image buffer and feed that image in the
subsequent IReadBlock calls? I think we should also think about the
Hi Jorge,
What I have in my mind is something like the DirectRasterIO implementation
in WCSDataset / WCSRasterBand (see wcsdataset.cpp). It appears that this
driver is suffering from the same issue, and intend to minimize the
roundtrips to the server as much as possible. It looks like this
Hello,
Context: GDAL WKT Raster driver
In my class derived from GDALRasterBand, I've overrided the methods:
- IReadBlock: Fetch a block from database
- IRasterIO: Should fetch several blocks, that cover an area, and add
them to papoBlocks (cache). The idea is to avoid rounds in the server
Jorge,
Did you call DropLock() right after copying the data on the newly allocated
block? This assertion shows the raster block have remained in locked state.
It's quite annoying if you find long executing times somewhere. Did you know
how much time required to fetch the data and place that into
2009/8/7 Tamas Szekeres szeker...@gmail.com:
Jorge,
Did you call DropLock() right after copying the data on the newly allocated
block? This assertion shows the raster block have remained in locked state.
OK, I commented this part during tests, -1 for me. The assertion
disappeared. Many
2009/8/7 Jorge Arévalo jorge.arev...@gmail.com
One issue with this concept would be related to the limited memory size
of
the particular machine, it may be more reasonable to copy the retrieved
blocks directly onto the output buffer if possible. In this case you
cannot
much rely on the
Just thinking out loadly;
Wouldn't it be easier to implement that cache at the driver level, just by
composing the raster in a temp image buffer and feed that image in the
subsequent IReadBlock calls? I think we should also think about the non
regular and overlapping blocks which should also be
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