Description of problem:
 
There is a problem when updating an RPM repository using workers. It seems to be a factor of the number of packages in the repo and the number of workers.

For example:
1) a repo with 4 packages and 6 workers fails; only 3 packages to be found. 
2) the same repo with 4 packages and 7 workers works fine; 4 packages found 
3) a repo with 5 packages and 6 workers works fine; 5 packages found
4) a repo with 5 packages and 9 workers fails; only 4 packages found


Version-Release number of selected component (if applicable):

createrepo-0.9.9-1



How reproducible:

100%  reproducible. 

TEST CASE 1: Even number of packages
Steps to Reproduce:
1. mkdir -p /tmp/test/RPMS
2. Put 4 RPMS into /tmp/test/RPMS
3.  ls -1 /tmp/test/RPMS/; 
     rm -rf /tmp/test/repodata/; 
     createrepo /tmp/test/ --checksum=sha --update --workers 6
     for i in /tmp/test/repodata/*.bz2; do bunzip2 -f $i;done;   
     sqlite3 /tmp/test/repodata/*primary*.sqlite 'select name, version, release from packages;'
 
Actual results:
4 RPMs will be listed (ls -1 /tmp/test/RPMS/), but only 3 RPMs will be returned in the sqlite database

Expected results:
4 RPMS should be found in the sqlite database

TEST CASE 2: Odd number of packages
Steps to Reproduce:
1. mkdir -p /tmp/test/RPMS
2. Put 5 RPMS into /tmp/test/RPMS
3.  ls -1 /tmp/test/RPMS/; 
     rm -rf /tmp/test/repodata/; 
     createrepo /tmp/test/ --checksum=sha --update --workers 9
     for i in /tmp/test/repodata/*.bz2; do bunzip2 -f $i;done;   
     sqlite3 /tmp/test/repodata/*primary*.sqlite 'select name, version, release from packages;'
 
Actual results:
5 RPMs will be listed (ls -1 /tmp/test/RPMS/), but only 4 RPMs will be returned in the sqlite database

Expected results:
5 RPMS should be found in the sqlite database

Additional info:

If you play around with the number of "--workers" it will work. For example, using 10 workers works for 5 RPMs (returns 5), but fails for 4 RPMs (returns 3). Using 9 workers works for 4 RPMs (returns 4) but not for 5 RPMs (returns 4).