Internal Rules for Determining Next Extent Size

This algorithm is used by BRCONNECT to determine the next extent size when a table needs adapting. For more information, see Adapt Next Extents.

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       1.      BRCONNECT works out the value of 10% of the space currently allocated to the table or index.

       2.      Using this value, BRCONNECT selects the next smaller category from the table TGORA (for tables) or IGORA (for indexes). The tables are shown below at the end of this section.

       3.      BRCONNECT looks up the table in the DD09L table and selects the category given. The DD09L is a data dictionary table in which most SAP tables are entered. For partition and LOB segments, BRCONNECT takes 10% of the category value and, using this new value, again selects the next smaller category. If the table is not there, size category 0 is assumed.

       4.      BRCONNECT chooses the larger of the values from steps 2 and 3, if necessary reducing it to the value of the init<DBSID>.sap parameter next_max_size.

       5.      If the required space is greater than the remaining free space in the tablespace and no file in the affected tablespace permits an autoextend, BRCONNECT reduces the value from step 4 to the size of the largest free space segment in the tablespace.

       6.      BRCONNECT compares the value from step 5 with the current value of NEXTEXTENT  and chooses the larger value.

       7.      If the next_specialparameter is defined for the table, BRCONNECT always uses this instead of the value determined so far.

       8.      BRCONNECT reduces the value from step 7 to the next smaller multiple of 5 times the database block size, to reduce free space wastage. The smallest possible value is 5 times the database block size.

       9.      BRCONNECT compares the value from step 8 with the current next extent size. If there is a difference, it changes the NEXTEXTENT storage parameter of the table or index to the newly determined next extent size.

NEXT Values in TGORA/IGORA

Size
category

NEXT value for table (KB)

NEXT value for indexes (KB)

0

40

40

1

160

80

2

640

160

3

2560

640

4

10240

2560

5

20480

5120

6

40960

10240

7

81920

20480

8

163840

40960

9

327680

81920

10

655360

163840

11

1310720

327680

12

2621440

655360

13

5242880

1310720

14

10485760

2621440