Maximum Parcel - Call-Level Interface Version 2

Maximum Parcel

Usage Notes

Maximum Parcel specifies whether the maximum parcel length is 32 KB, 64 KB, or 1 MB. The exact size depends upon numerous factors related to the nature and structure of a specific request.

Language	Variable Name
COBOL:	MAXIMUM-PARCEL
C: DBCAREA.H:	maximum_parcel

Routine	Action Taken
DBCHINI:	writes
DBCHCL:	reads (CON; RESUP; IRQ)

Used by	Action Taken
application program	writes

Maximum Parcel is initialized to the default value provided for Maximum Parcel in the site’s CLISPB. If the value is not appropriate for the application, the application, before calling DBCHCL for Connect, Run Startup and Initiate Request, may set Change Options to Y and Maximum Parcel to one of the following values:

O, if the original limit of 32 KB is the maximum size of one parcel.

H, if the limit of 64 KB or 1 MB (APH-requests/extended response support exists at the server) is the maximum size of one parcel.

When the actual row size to be returned is:

Less than 32 KB and the response buffer is not large enough to hold a parcel, the Teradata server returns a 3116 error. In response, CLI will retry with a larger buffer size.

Greater than 32 KB and the response buffer is not large enough to hold a parcel, the Teradata server returns a 3115 error. CLI will retry with a larger buffer size only if Maximum Parcel is set to H. If Maximum Parcel is set to O, CLI will not retry the 3115 error with a larger buffer size, but will return the 3115 error to the user. This prevents retry looping.

Greater than 64 KB and the response buffer is not large enough to hold a parcel, the Teradata server returns a 3177 error followed by an ErrorInfo parcel with an InfoType of 1 (PCLBUFFERSIZE). CLI will retry with a larger buffer size only if Maximum Parcel is set to H. If Maximum Parcel is set to O, CLI will not retry the 3177 error with a larger buffer size, but will return the 3177 error to the user. This prevents retry looping.

Determining Maximum Parcel Request Size

Maximum parcel size is determined by which of the two parcel header formats is used. The maximum lengths are as shown below:

When maximum_parcel is 'O':

- buffer size limit: ~32KB

When maximum_parcel is 'H:'

- buffer size limit: ~64KB (APH-requests is 0)

When maximum_parcel is 'H:'

- buffer size limit: ~1MB (APH-requests is non-zero)