11. The Asterisk Database
The problem with using variables in the dialplan is that it is vulnerable to a system crash or a restart of Asterisk. If either of these things happens, the variable is either erased or reset to its default value. This limitation precludes certain implementations entirely. In call forwarding or a calling card application, some values (the remaining balance, for example) need to be stored in a persistent manner so that they can be recalled after a restart. The Asterisk database (AstDB) serves this purpose.
11.1 The Asterisk Database
Those needing a database for Asterisk applications often ask how well the AstDB performs. The answer, to the extent there’s a simple one, is that it depends on what you are doing. If you ...