Thumb rules for table buffering in SAP


Important points for buffering of Table:

  • A buffered table does not use indexes and instead always under full table scan.
  • Select statement with order by primary key only use buffer, any other order by condition bypass buffer.
  • Big tables should not be buffered, use index instead.
  • Table which has frequent operations (insert/update/delete) should not be buffered. If percentage of inserts /updates /deletes more than 20% of total access do not buffer the table. It causes additional I/O with database. This increases many times if there is more than one SAP dialogue instances (Application Servers).
  • This is further depended on the parameters rdisp/bufrefmode and rdisp/bufreftime
  • If a poorly performing partially buffered table is frequently accessed by index range scan, better option is to find a generic key and use of generic key buffering.
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