How to Find the Size of a DB2 Database

DB2′s get_dbsize_info Function

db2 => connect to dd

 

   Database Connection Information

   Database server        = DB2/LINUX 8.2.8
   SQL authorization ID   = DB2UDB
   Local database alias   = dd

db2 => call get_dbsize_info(?,?,?,-1)

 

  Value of output parameters
  --------------------------
  Parameter Name  : SNAPSHOTTIMESTAMP
  Parameter Value : 2014-08-10-15.53.40.550222

 

  Parameter Name  : DATABASESIZE
  Parameter Value : 216819380224

 

  Parameter Name  : DATABASECAPACITY
  Parameter Value : 439644852736

 

  Return Status = 0

 

db2 =>

 

With a bit of math,  we can see that the size of the database is 201.92 GB. These numbers include only used pages  in the tablespace. This means that it essentially covers table data and index data and not much else. It also means that if you have DMS tablespaces with a large amount of free space, you may have more space actually taken up on disk than the value of DATABASESIZE as reported here.

 

The DATABASECAPACITY is calculated by adding up pages that have been allocated but not used in DMS tablespaces and filesystem free space for filesystems that hold SMS tablespaces. There are problems inherent in that, of course – you may have a lot of filesystem space where DMS containers reside that would not be reflected in DATABASECAPACITY until you extend the tablespace(s) to use them, and you may also have SMS tablespaces in a filesystem where you really shouldn’t use the filesystem up to 100%.