abright (12/4/2015)
To pinpoint the cause and change the code would prompt a lengthy QC process and the customer wants this fixed yesterday.
The earlier you start, the sooner it'll be done
I tried purging the database and rebuilding the operative indices, and DBCC CheckDB returned 0 errors. Should I try to compress the database? Should I reorganize the indices?
No, and no.
Deadlocks are almost always down to either code or inefficient indexes. Yes, you could have had the system working for years, but your data volumes have grown over that time and what were once fast queries on tiny amounts of data are now on larger amounts of data, hence are slower. Slower queries are more likely to deadlock.
Go through my article, identify the cause, put the necessary changes into QA and tell the customer that you're working on it as fast as possible
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability