Field Buffer Calculation

This appendix explains how to calculate a field buffer when migrating a Tuxedo environment that uses FML to Tmax.

1. Tmax Field Calculation Method

The following table shows how to calculate the buffer size based on the field type.

Filed Type Size

String

Header 4 bytes + Date length + Null 1 byte + Padding

Carray

Header 4 bytes + Specified Length + 4 (Specified Length) bytes + Padding

Char

Header 4 bytes, Data 4 bytes

Short

Header 4 bytes, Data 4 bytes

Long

Header 4 bytes, Data 4 bytes

Float

Header 4 bytes, Data 4 bytes

Double

Header 4 bytes, Data 8 bytes + Padding (4 bytes)

The following shows how to calculate the size of a buffer.

Buffer size = FDL buffer header + (Field header(4) + Data length + Padding) * Input counts

Data must be aligned on an 8-byte boundary for padding.
Example

The following shows how to calculate Tmax FD values.

F1 integer
F2 long
F3 float
F4 double
F5 STRING length 10
F6 STRING length 19
F7 CARRAY length 22

The buffer size is calculated based on the field type as shown below.

F1 integer
F2 long
F3 float
F4 double
F5 STRING length 10
F6 STRING length 19
F7 CARRAY length 22

F1 integer : 8 (Header field(4) + 4)
F2 long : 8 (Header field(4) + 4)
F3 float : 8 (Header field(4) + 4)
F4 double : 16 (Header field(4) + 8) + 4(padding)
F5 STRING length 10 : 16  (Header field(4) + 10 + 1(null)) + 1
F6 STRING length 19 : 24  (Header field(4) + 19 + 1(null))
F7 CARRAY length 22 :  32  (Header field(4) + 22 + 4(int for specifying the length)) + 2
Total : 112

Based on the buffer usage calculation method, a 179,200-byte buffer is required to send 200 records.

fdl buffer header(8) + (length of a record * count)
8 + (112 * 200)  = 179200 byte

2. Tuxedo FML16 Calculation Method (Tuxedo 6.4)

The following shows how to calculate the buffer size based on the field type.

Filed Type Size

String

Header 4 bytes, Null 1 byte

Carray

Header 4 bytes

Char

Header 2 bytes, Data 2 bytes

Short

Header 2 bytes, Data 2 bytes

Long

Header 2 bytes, Data 4 bytes

Float

Header 2 bytes, Data 4 bytes

Double

Header 2 bytes, Data 8 bytes

FML16 uses 2 bytes for both the header field and the data field, while FML32 and Tmax use 4 bytes for these fields. In FML32, the calculation method results in a small difference between the field descriptor (FD) size and the actual data size. In contrast, FML16 shows a more significant difference. When migrating from Tuxedo to Tmax, the field buffer size must be calculated accurately.