Affinity tables and indexes

How to calculate the space required for the DB2® tablespace and DB2 indexes for Affinity data.

To calculate the space, in KB, to allocate for the DB2 tablespace and the DB2 indexes required for the Affinity collection, estimate the total number of rows. In this example, there are three tables:

CIU_AFF_INDEX. This table holds the group count for all the different affinity types. The number of rows is fixed at 20.
NUM_ROWS = 20
CIU_AFF_CMD_DATA. The number of rows for this table is an estimate of the total number of commands that cause affinities for each program in each region. Calculate this number from the following values; see Table 1.
  • NUM_AFF_PROG
  • AVG_AFF
  • NUM_REGION_D

The number of rows for the CICS® table can be calculated as follows:

NUM_ROWS = (NUM_AFF_PROG * AVG_AFF * NUM_REGION_D)
CIU_AFF_GROUP_DATA. The number of this table is an estimate of how many affinity groups are required. Affinity commands stored in the CIU_AFF_CMD_DATA table are grouped by affinity type, for example TSQueue type. Assume there are four affinity commands per group.
NUM_ROWS = (NUM_AFF_PROG * AVG_AFF * NUM_REGION_D) / 4
Use the value calculated for NUM_ROWS and the values for ROW_SIZE and PERCENT_FREE in Table 1 to calculate the PRIQTY and SECQTY as described in Figure 1 for the Affinity tablespace.
Table 1. Worksheet for Affinity tablespace
Tablespace Row_Size Percent_Free PRIQTY SECQTY
CIUAFFD      
CIU_AFF_INDEX 6 15    
CIU_AFF_CMD_DATA 61 15    
CIU_AFF_GRP_DATA 367 15    
Indexes        
X4AFFG11 10 20    
X4AFFG12 81 20    
X4AFFC11 57 20    
X4AFFC12 53 20    
X4AFFI11 6 20    
X3GRPDAT 255 20    
X1GRPDAT 10 20    
X2AFFDAT 22 20    
X1AFFDAT 42 20    

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Timestamp icon Last updated: Friday, 7 February 2014


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