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I20060215-0010 The shutdown of my runtime workbench took a long time with no progress (message "Saving Workspace"), so I suspended all threads and checked what was going on. I found that all the time was spent in org.eclipse.jdt.internal.core.builder.State.write(..) in the last big loop. Some numbers: references.elementSize= 1864 keyTable.length= 3453 internedQualifiedNames.size= 12831 internedSimpleNames.size= 12097 For every element in the keyTable, there are two loops like this: for (int j = 0; j < qLength; j++) out.writeInt(internedQualifiedNames.indexOf(qNames[j])); Unless I miss something fundamental here, I think it is very inefficient to loop over these big ArrayLists again and again comparing all the char[][] and char[][][] just to find a matching element. I guess a hash table would be appropriate to speed this up. I disabled autobuild and killed the build job shortly before - don't know if that has an influence here.
indexof is using == to do the comparison so unless the interned arrays are 100,000 elements then I doubt this the reason it was slow to save your workspace.
java.util.ArrayList#indexOf(..) uses Object#equals(..) to find elements. I've set a breakpoint after the loop and that breakpoint was not hit for a long time, so I'm pretty sure the time was burned in this loop. I also suspended the vm manually, and it was inside indexOf(..) most of the time. I don't know how big qNames and sNames grow, but if I assume they contain just 1 element, then the number of calls to char[]#equals(..) is in average: references.elementSize * 2 * (internedQualifiedNames.size + internedSimpleNames.size) / 2 = 46'465'792 calls
What does equals do for a char[] -> == I have no idea what you think that expression meant.
> What does equals do for a char[] -> == Of course, but there are still (rough guess) more than 46 Million calls to an equals method. And that is a lot, even if they were plain == operations.
Fixed. Will have a big impact on very large projects.
Verified for 3.2 M6 using warm-up build I20060327-0010. Unfortunately, close workspace operation does not long enough on our full source workspace to add a specific performance test case...
