1. Summarise the issue (what were doing, what went wrong?)

darcs convert --debug-verbose on a "hashed" repo with 18,000 patches in 
it. 

Every few seconds, the work pauses while darcs reports "About to create 
patch index".

2. What behaviour were you expecting instead?

I expect darcs to create the patch index once at the end, which is 
presumably notably faster on large repo.

3. What darcs version are you using? (Try: darcs --exact-version)

Darcs 2.9.6

4. What operating system are you running?
  
Ubuntu Linux 12.04 on EC2.

Mark, can you try again with patch1027 (which is now in screened)?

I pulled the patch, and re-compiled. "darcs --version" now reports 2.9.7 
+ 48 patches.

I re-tried with darcs convert --debug-verbose, and I still see this 
regularly in the output:

 About to create patch index...
 Patch index created

Are you getting a different result for the same command? I imagine you 
could just well substitute the darcs repo instead of the one I have.

Can anybody reproduce this? Looks potentially tricky to do so, need to 
create some repository that will trigger more than one patch index build 
but not too many

Mark: don't we have options to disable the patch index? (as a 
workaround)

I'm afraid this one will likely drift to the bottom of priority pile as 
things go :-(

Let's just "give up" for now. "darcs convert" eventually produces the 
correct result, and the only cases that these benefits are the 
increasingly small number of darcs 1.x users, and it's only a one-time 
slowness. Given the project resource constraints, I agree this shouldn't 
be a priority.

The following patch sent by Guillaume Hoffmann <guillaumh@gmail.com> updated issue issue2274 with
status=resolved;resolvedin=2.10.0 HEAD

* Resolve issue2274: create patch index only with commands that take a lock 
Ignore-this: dd65303a8ec0e308118f0e3dca9df14b