Asterisk: The Future of Telephony, 2nd Edition

Storing Call Detail Records

Call Detail Records (CDR) contain information about calls that have passed through your Asterisk system. They are discussed further in Chapter 13. This is a popular use of databases in Asterisk because CDR can be easier to manage if you store the records in a database (for example, you could keep track of many Asterisk systems in a single table).

Setting the systemname for Globally Unique IDs

CDRs consist of a unique identifier and several fields of information about the call (including source and destination channel, length of call, last application executed and so forth). In a clustered set of Asterisk boxes, it is theoretically possible to have duplication among unique identifiers since each Asterisk system considers only itself. To address this, we can automatically append a system identifier to the front of the unique ID by adding an option to /etc/asterisk/asterisk.conf. For each of your boxes, set an identifier by adding something like:

[options]
systemname=toronto

Let’s create a table in our database to store CDR. Log in to the PostgreSQL server with the psql application:

# psql -U asterisk -h localhost asterisk
Password:

And create the asterisk_cdr table:

asterisk=> CREATE TABLE asterisk_cdr ( id bigserial NOT NULL, calldate timestamptz, clid varchar(80), src varchar(80), dst varchar(80), dcontext varchar(80), channel varchar(80), dstchannel varchar(80), lastapp varchar(80), lastdata varchar(80), duration int8, billsec int8, disposition varchar(45), ...