add key on pairs table as an attempt to speed up ProcessPairs stage
add key on pairs table as an attempt to speed up ProcessPairs stage

Ensembl/ensembl,at7/ensembl,Ensembl/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,mjg17/ensembl,danstaines/ensembl,at7/ensembl,muffato/ensembl,mjg17/ensembl,muffato/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,Ensembl/ensembl,danstaines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,muffato/ensembl,at7/ensembl,at7/ensembl,muffato/ensembl