Microsoft Dynamics NAV automatically buffers inserts in order to send them to SQL Server at one time.
By using bulk inserts the number of server calls is reduced, thereby improving performance.
Bulk inserts also improve scalability by delaying the actual insert until the last possible moment in the transaction. This reduces the amount of time that tables are locked; especially tables that contain SIFT indexes.
Application developers who want to write high performance code that utilizes this feature should understand the following bulk insert constraints.
Bulk Insert Constraints
If you want to write code that uses the bulk insert functionality, you must be aware of the following constraints.
Records are sent to SQL Server when the following occurs:
-
You call
COMMIT
to commit the transaction. -
You call
MODIFY
orDELETE
on the table. -
You call any
FIND
orCALC
methods on the table.
Records are not buffered if any of the following conditions are met:
-
The application is using the return value from an
INSERT
call; for example, "IF (GLEntry.INSERT) THEN
". -
The table that you are going to insert the records into contains any of the following:
-
BLOB fields
-
Variant fields
-
RecordID fields
-
Fields with the AutoIncrement property set to Yes
-
The following code example cannot use buffered inserts because
it contains a FIND
call on the GL/Entry table
within the loop.
Copy Code | |
---|---|
IF (JnlLine.FIND('-')) THEN BEGIN GLEntry.LOCKTABLE; REPEAT IF (GLEntry.FINDLAST) THEN GLEntry.NEXT := GLEntry."Entry No." + 1 ELSE GLEntry.NEXT := 1; // The FIND call will flush the buffered records. GLEntry."Entry No." := GLEntry.NEXT ; GLEntry.INSERT; UNTIL (JnlLine.FIND('>') = 0) END; COMMIT; |
If you rewrite the code, as shown in the following example, you can use buffered inserts.
Copy Code | |
---|---|
IF (JnlLine.FIND('-')) THEN BEGIN GLEntry.LOCKTABLE; IF (GLEntry.FINDLAST) THEN GLEntry.Next := GLEntry."Entry No." + 1 ELSE GLEntry.Next := 1; REPEAT GLEntry."Entry No.":= GLEntry.Next; GLEntry.Next := GLEntry."Entry No." + 1; GLEntry.INSERT; UNTIL (JnlLine.FIND('>') = 0) END; COMMIT; // The inserts are performed here. |