Impcat of vc5.5 db corruption

Have few queries for sql 2008 database configured for my vc 5.5...both running on diff win 2008 machines..

>msg  given below -relate to any db corruption ?as got while trying to login into vc,later logged in  and got same error when trying to search anything in inventory..
"The request failed because the remote server “Vcenter name / ip” took too long to respond. (The command has timed out as the remote server is taking too long to respond) OR "{Connection Time-out while waiting in the queue}"

>how to identify if db for vc is corrupted any symptoms,logs we have to search, where to diagnose if db is corrupted?

> Found Memory was almost consumed  by java.exe and vpxd.exe..is this related to db corruption or any other symptom ?
> cpu was almost 100 % on Vc
> on db all looks fine but free space in db drive was only 1-2 gb ..so that could be reason to corrupt the db ?
> what is db shrink and when n why it is required if its my vc's databse ? can we automate db shrink if its needed.
>what is db reinitialize and when & why it is required for my vc'sdb ?
have been informed that db was corrupted hence restored from backup,i just need to check what actually occurred and how it has been resolved. any way i can check in logs ?