Changes between Version 12 and Version 13 of UserDocs/GdalWarp

Timestamp:

Jun 8, 2011, 1:27:33 PM (13 years ago)

Author:

maphew

Comment:

added section for memory allocation error

UserDocs/GdalWarp

@@ -41 +41 @@
 
 Caution : increasing the value of the -wm param may lead to loss of performance in certain circumstances, particularly when gdalwarping *many* small rasters into a big mosaic. See http://trac.osgeo.org/gdal/ticket/3120 for more details
+
+=== Error allocating memory ===
+
+In some cases using  `--config GDAL_CACHEMAX xxx -wm xxx` can be detrimental. A symptom of this is:
+{{{
+ERROR 2: Out of memory allocating 365425784 byte destination buffer.
+}}}
+
+Our understanding is that Win32 processes are frequently subject to memory fragmentation problems and so even in a process with - in theory - 2GB of heap RAM space available it is still often difficult to allocate large blocks of memory. In this case with -wm 500 set the main warp buffers can be quite large (364MB for the example) and it seems it has failed to allocate the buffer. Use more modest buffers (or not use the options at all) or else get a 64bit executable for gdalwarp. 
+
+Source:
+   * [http://www.mail-archive.com/gdal-dev@lists.osgeo.org/msg11235.html gdalwarp: ERROR 2: Out of memory allocating {number} byte destination buffer]
+
 
 === Warp and Cache Memory: Technical Details ===