kamailio/modules/db_flatstore

1. Db_flatstore Module

Jan Janak

FhG FOKUS


Copyright � 2004, 2005 FhG FOKUS
Revision History
Revision $Revision$ $Date$
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1.1. Overview

Db_flatstore is one of so-called SIP Router database modules. It does
not export any functions executable from the configuration scripts, but
it exports a subset of functions from the database API and thus other
modules can use it as a database driver, instead of, for example, the
Mysql module.

The module does not implement all functions of the database API, it
supports only one function, insert. This means that the module is
limited but very fast. It is especially suitable for storing accounting
information on sites with extremely high traffic. If MySQL is too slow
or if you get a huge amount of accounting data then you can consider
using this module. Please note that the acc module is the only module
that was tested with the flastore module.

The format of the files produced by this module is plain text. Each
line consists of several fields, fields are separated by the "|"
character (vertical bar). New information is always appended at the end
of the file. Searching, deleting and updating of existing data is not
supported by the module.

The acc module can be configured to use db_flatstore module as database
backend using the db_url_parameter:
modparam("acc", "db_url", "flatstore:/var/log/acc")

This configuration option tells the acc module that it should use the
db_flatstore module and the db_flatstore module should create all files
in the /var/log/acc directory. The directory must exist and SIP Router
processes must have permissions to create files in that directory.

Name of files in that directory will follow the following pattern:
_.log

For example, entries writen by the SIP Router process 8 into the acc
table would be written in file acc_8.log. For each table there will be
several files, one file for every SIP Router process that wrote some
data into that table. The main reason why there are several files for
each table is that it is much faster to have one file per process,
because it does not require any locking and thus SIP Router processes
will not block each other. To get the complete data for a table you can
simply concatenate the contents of files with the same table name but
different process id.

1.1.1. Rotating Log Files

The module implements a SIP Router management interface command called
flatstore.rotate. When SIP Router receives the command it will close
and reopen all files used by the db_flatstore module. The rotation
itself has to be done by another application (such as logrotate).
Follow these steps to rotate files generated by the db_flatstore
module:
* Rename the files that you want to rotate:
cd /var/log/acc
mv acc_1.log acc_1.log.20050605
mv acc_2.log acc_2.log.20050605
mv acc_4.log acc_3.log.20050605
...
Note that at this point SIP Router will still be writing all data
into the renamed files.
* Send SIP Router the management command to close and reopen the
renamed files:
sercmd flatstore.rotate
This will force SIP Router to close the renamed files and open new
ones with original names, such as acc_1.log. New files will be open
at the point when SIP Router has some data to write. It is normal
that the files will be not created immediately if there is no
traffic on the SIP server.
* Move the renamed files somewhere else and process them.

1.2. Parameters

Revision History
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1.2.1. flush (integer)

Enable or disable flushing after each write.

Default value is 1.