Hi Madhukar,
have you analyzed the Short dump in ST22? You can get clue from the ST22 short dump, can you share the st22 details.
Have you checked if there are any requests which might be undergoing compression n its active?
Whats the support package n version you are using ?
Check below note for support pack related issue
1576671 - MSSQL; maximum number of partitions reached; UPDATERULES
Regards
KP