Knowledgebase

Calculating Memory Usage

The FairCom Server startup memory requirements can be reasonably approximated with the following equation:

Base line Memory =

Server EXE size + 1 MB +

Communications Library size (if applicable) +

Data cache (DAT_MEMORY) +

Index buffer (IDX_MEMORY) +

(900 bytes * Number of files (FILES)) +

(325 bytes * Maximum number of connections (CONNECTIONS)) +

(16000 bytes * Number of actual connections) +

(256 bytes per connection per file actually opened))

Note the following points:

• DAT_MEMORY and IDX_MEMORY default to 225,000 bytes each.
• FILES defaults to 100.
• CONNECTIONS default to 128.
• IDX_MEMORY is the MAX of:
  • IDX_MEMORY or
  • 3 * CONNECTIONS * (PAGE_SIZE + 400), where PAGE_SIZE defaults to 8192.

The following locking/transaction processing related items should be considered when approximating the FairCom Server dynamic memory requirements:

• Each record locked consumes 24 bytes.

For transaction processing files only:

• Each data record written consumes (record length + 42) bytes.
• Each index operation consumes (key length + 42) bytes.

See also:

• Server Memory Calculations