You must define whether and how a table is buffered in the technical settings for the table. There are three possibilities here:
1) Buffering not permitted:
Table buffering is not permitted, for example because application programs always need the most recent data from the table or the table is changed too frequently.
2) Buffering permitted but not activated:
Buffering is permitted from the business and technical points of view. Applications which access the table execute correctly with and without table buffering. Whether or not table buffering will result in a gain in performance depends on the table size and access profile of the table (frequency of the different types of table access). Table buffering is deactivated because it is not possible to know what these values will be in the customer system. If table buffering would be advantageous for the table size and access profile of the table, you can activate it in the customer system at any time.
3) Buffering activated:
The table should be buffered. In this case you must specify a buffering type. Buffering types:
a) Single-Record buffering With single-record buffering, only the records that are actually read are loaded into the buffer. Single-record buffering therefore requires less storage space in the buffer than generic and full buffering. The administrative costs in the buffer, however, are greater than for generic or full buffering. Considerably more database accesses are necessary to load the records than for the other buffering types.
When Should you Use Single-Record Buffering?
Single-record buffering should be used particularly for large tables where only a few records are accessed with SELECT SINGLE. The size of the records being accessed should be between 100 and 200 KB. Full buffering is usually more suitable for smaller tables that are accessed frequently. This is because only one database access is necessary to load such a table with full buffering, whereas several database accesses are necessary for single-record buffering.
b) Generic buffering With generic buffering, all the records in the buffer whose generic key fields match this record are loaded when one record of the table is accessed. The generic key is a part of the primary key of the table that is left-justified.
c) Full buffering With full buffering, either the entire table is in the buffer or the table is not in the buffer at all. All the records of the table are loaded into the buffer when one record of the table is read.
When Should you Use Full Buffering?
When deciding whether a table should be fully buffered, you should take into account the size of the table, the number of read accesses, and the number of write accesses. Tables best suited to full buffering are small, read frequently, and rarely written. Full buffering is recommended in the following cases: Tables up to 30 KB in size. If a table is accessed frequently, but all accesses are read accesses, this value can be exceeded. However, you should always pay attention to the buffer utilization. Larger tables where large numbers of records are frequently.
