Tech. Note 3: Compare/Merge LARGE files

Guiffy's default Show Options are setup to implement "Folded Compare/Merge Views" for Larger files (Over 400KB). "Folded Compare/Merge Views" display only the differences within a few (default of 8) lines of context. This dramatically reduces the memory and time required to display large file compares or merges.

But, if you need to see all of the file in the compare view -or- there are very LARGE differences in the files --- you will need to give Guiffy more memory to work with. Edit the guiffy.lax file to increase the maximum heap size.

Edit guiffy.lax, change the heap.size.max line (usually about line #68). It will look like this:
lax.nl.java.option.java.heap.size.max=134217728
Change the maximum value to between 2/3 - 3/4 of your system's RAM (if you set it to more than the available RAM, thrashing may occur).

Note: With the default 128MB max. heap size, Guiffy will usually display up to about 200K lines (7MB). Allow about 35% more heap space for 3-way merges.

If the compare/merge of your large file takes a long time and you know there are big differences between the files, you may consider tuning the Maximum Block Size to improve performance. After the LAX.COMMAND.LINE.ARGS line:
lax.command.line.args=$CMD_LINE_ARGUMENTS$
add the line:
lax.nl.java.option.additional=-Dguiffy.block.max=BBBB
Where BBBB= The Maximum Change Block Size in number of lines. A smaller Maximum Block Size will improve the speed of the compare through large differences which can even exceed the maximum size. But, smaller Block Sizes may result in a verbose expression of the differences. The default is 2000.