Hi everyone
I have followed up with NI tech support on this issue, and have sent them a VI to test. They have confirmed that the Slow Save issue does indeed exist with LV2009, and that it is a function of the size of the VI. It is caused by a change in the compiler, which produces more efficient code, but slower compiles. It seems that one needs to create more SubVIs with LV2009, with larger VIs (perhaps > 500 kB on disk).
However, by accident, I discovered a work around. While experimenting recently with my VI, by eliminating blocks of code to see how this affects the save time, I discovered that, if the VI has a broken arrow, a save takes only 3-5 sec, not 30 sec! It seems that, as long as I maintain a broken arrow (e.g. by dropping an unused Arithmetic function somewhere on my BD), I can go ahead and code all day, saving every few minutes, and only lose 3-5 sec each save. This seems to be independent of how drastic is the code edit. In between, I can temporarily delete the unused function to see if I get an unbroken arrow (but NOT issue a SAVE!), and then issue an Undo Cmd to restore the unused function. Finally, when done, I can delete the unused function, and do a final save and compile. NI thinks this is a good workaround.
FYI, here is the full response on this issue from NI:
" There are different kinds of unsaved changes (front panel item moved, BD item moved, VI needs to be recompiled). When the recompile flag is set LabVIEW has to recompile the source and save it within the VI. If a block diagram item simply moves, LabVIEW only has to save the BD and not recompile the code which goes much shorter. You can test this out by saving after simply moving a wire. You will see that this save will be dramatically faster. While this doesn't help alleviate the problem it should help understand where the longer time is coming from, the compile process.
I tried to see if this was caused by a bug in a particular part of code or the simple fact that our compile process takes longer. Because of the proportional delay based on how much I disabled I think it is safe to say that this is simply a product of compilation being slower. We have added many compiler settings that are aimed to improve the runtime performance.
Because we are looking for more optimizations it is logical to assume that the compile time will be longer. Because of the way LabVIEW works we need to compile the code when we save. The decision was made that a sacrifice of save speed (compilation) was okay if it meant faster runtime performance. I have presented all of this to R&D and they have reluctantly confirmed everything. I can understand why you are affected by this and I have filed a Corrective Action Request (Bug Report) on your behalf which is #225473."
