It is Microsoft SMS (systems management server), we used a 8 procs, 4GB RAM server as central publisher...dedicated distributor...SQL 2K EE with SP4 on windows 2K3 servers. This system worked fine for almost 2 years, recently log reader agent stops working... 3 weeks ago, the log reader agent stopped working with error message "The process could not execute 'sp_replcmds' ", we gave a large query time-out value, it works fine after that... But now it gave a different error "The process is running and is waiting for a response from one of the backend CONNECTION" We found when the publisher was doing db-reindexing and DBCC check DB, the log reader agent will stop with the above error...is there some blocking issue? Also we know the server load is heavy, when the load on publisher decreases, log reader agent starts working properly...But we need some proof to convince the customer about this, which counter should we collect regarding this? thanks a lot.