SAP Cursor Cache

Definition

The SAP cursor cache helps to improve system performance by reducing the number of parsing of SQL statements; it is database-dependent. The SAP cursor cache is only slightly different for Oracle, Informix and SAP DB. It is totally different for AS/400 and MS SQL Server.

There are two types of cursor caches:

Statement ID cache

Statement cache

Changing the SAP cursor cache parameter value in the default profile will affect other areas as well. You are therefore advised not to tune it without the recommendation of a qualified SAP expert.

Statement IDs and the Statement Analyzer

The source of each SQL statement in the SAP System (ABAP, DYNP, the C modules of the database interface) assigns an ID to its Open SQL / Native SQL etc. statement. The statement ID includes:

Module name (report name)

Statement number (line number)

Timestamp (time of ABAP generation)

The statement ID provides an easy way to recognize statements. There may be different statement IDs for one statement (for example, different ABAP programs doing the same SELECT ). The Statement Analyzer eliminates such duplicities. When it receives an SQL statement (in control block form), this database interface module checks if the statement is simple (for example, SELECT * FROM T100 WHERE... =... AND... =... ), or complex (for example, SELECT * FROM T100 WHERE... <... AND... >... ). If the statement ID is simple, the Statement Analyzer assigns a 'normalized' statement ID.

The analyzer is called by the RSQL or Open SQL interface. If it is able to assign a normalized ID, the original ID (if existing) is replaced.