syslog-ng Open Source Edition 3.25 - Administration Guide

sql: Storing messages in an SQL database

The sql() driver sends messages into an SQL database. Currently the Microsoft SQL (MSSQL), MySQL, Oracle, PostgreSQL, and SQLite databases are supported.

Declaration:

sql(database_type host_parameters database_parameters [options]);

The sql() driver has the following required parameters: type(), database(), table(), columns(), and values().

The table and value parameters can include macros to create tables and columns dynamically (for details, see Macros of syslog-ng OSE).

Inserting the records into the database is performed by a separate thread. The syslog-ng application automatically performs the escaping required to insert the messages into the database.

destination d_sql {
    sql(type(pgsql)
    host("logserver") username("syslog-ng") password("password")
    database("logs")
    table("messages_${HOST}_${R_YEAR}${R_MONTH}${R_DAY}")
    columns("datetime", "host", "program", "pid", "message")
    values("{$R_DATE}", "${HOST}", "${PROGRAM}", "${PID}", "${MSGONLY}")
    indexes("datetime", "host", "program", "pid", "message"));
};

destination d_sql {
    sql(type(pgsql)
    host("logserver") username("syslog-ng") password("password")
    database("logs")
    table("messages_${HOST}_${R_YEAR}${R_MONTH}${R_DAY}")
    columns("datetime varchar(16)", "host varchar(32)", "program  varchar(20)", "pid varchar(8)", "message  varchar(200)")
    values("${R_DATE}", "${HOST}", "${PROGRAM}", "${PID}", "${MSGONLY}")
    indexes("datetime", "host", "program", "pid", "message"));
};

Using the sql() driver with an Oracle database

The Oracle sql destination has some special aspects that are important to note.

• The hostname of the database server is set in the tnsnames.ora file, not in the host parameter of the sql() destination.

  If the tnsnames.ora file is not located in the /etc directory (or in the /var/opt/oracle directory on Solaris), set the following Oracle-related environment variables, so syslog-ng OSE will find the file: ORACLE_BASE, ORACLE_HOME, and ORACLE_SID. For details, see the documentation of the Oracle Instant Client.

• You cannot use the same database() settings in more than one destination, because the database() option of the SQL driver is just a reference to the connection string of the tnsnames.ora file. To overcome this problem, you can duplicate the connections in the tnsnames.ora file under a different name, and use a different table in each Oracle destination in syslog-ng OSE.

• As certain database versions limit the maximum length of table names, macros in the table names should be used with care.

• In the current version of syslog-ng OSE, the types of database columns must be explicitly set for the Oracle destination. The column used to store the text part of the syslog messages should be able to store messages as long as the longest message permitted by syslog-ng, therefore it is usually recommended to use the varchar2 or clob column type. (The maximum length of the messages can be set using the log-msg-size() option.) For details, see the following example.

• The Oracle Instant Client used by syslog-ng OSE supports only the following character sets:

  • Single-byte character sets: US7ASCII, WE8DEC, WE8MSWIN1252, and WE8ISO8859P1

  • Unicode character sets: UTF8, AL16UTF16, and AL32UTF8

destination d_sql {
  sql(type(oracle)
  username("syslog-ng") password("password")
  database("LOGS")
  table("msgs_${R_YEAR}${R_MONTH}${R_DAY}")
  columns("datetime varchar(16)", "host varchar(32)", "program varchar(32)", "pid varchar(8)", "message varchar2")
  values("${R_DATE}", "${HOST}", "${PROGRAM}", "${PID}", "${MSGONLY}")
  indexes("datetime", "host", "program", "pid", "message"));
};

LOGS =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)
(HOST = logserver)
(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = EXAMPLE.SERVICE)
)
)

Using the sql() driver with a Microsoft SQL database

The mssql database driver can access Microsoft SQL (MSSQL) destinations. This driver has some special aspects that are important to note.

• The date format used by the MSSQL database must be explicitly set in the /etc/locales.conf file of the syslog-ng server. For details, see the following example.

• As certain database versions limit the maximum length of table names, macros in the table names should be used with care.

• In the current version of syslog-ng OSE, the types of database columns must be explicitly set for the MSSQL destination.

  Caution: The following column types cannot be used in MSSQL destinations: nchar, nvarchar, ntext, and xml.

• The column used to store the text part of the syslog messages should be able to store messages as long as the longest message permitted by syslog-ng. The varchar column type can store maximum 4096 bytes-long messages. The maximum length of the messages can be set using the log-msg-size() option. For details, see the following example.

• Remote access for SQL users must be explicitly enabled on the Microsoft Windows host running the Microsoft SQL Server. For details, see Configuring Microsoft SQL Server to accept logs from syslog-ng.

destination d_mssql {
sql(type(mssql) host("logserver") port("1433")
  username("syslogng") password("syslogng") database("syslogng")
  table("msgs_${R_YEAR}${R_MONTH}${R_DAY}")columns("datetime varchar(16)", "host varchar(32)",
  "program varchar(32)", "pid varchar(8)", "message varchar(4096)")
  values("${R_DATE}", "${HOST}", "${PROGRAM}", "${PID}", "${MSGONLY}")
  indexes("datetime", "host", "program", "pid"));
};

[default]
date = "%Y-%m-%d %H:%M:%S"

The way syslog-ng interacts with the database

Used SQL operations by syslog-ng

Create table:

• If the given table does not exist, syslog-ng tries to create it with the given column types.

• The syslog-ng OSE application automatically creates the required tables and columns, if the user account used to connect to the database has the required privileges.

• If syslog-ng cannot create or alter a table, it tries to do it again when it reaches the next time-reopen().

Alter table:

• If the table structure is different from given structure in an existing table, syslog-ng tries to add columns in this table but never will delete or modify an existing column.

• If syslog-ng OSE cannot create or alter a table, it tries to do it again when reach the next time-reopen().

• The syslog-ng OSE application requires read and write access to the SQL table, otherwise it cannot verify that the destination table exists.

Insert table:

• Insert new records in a table.

• Inserting the records into the database is performed by a separate thread.

• The syslog-ng OSE application automatically performs the escaping required to insert the messages into the database.

• If insert returns with error, syslog-ng tries to insert the message +two times by default, then drops it. Retrying time is the value of time-reopen().

Encoding

The syslog-ng OSE application uses UTF-8 by default when writes logs into database.

Start/stop and reload

Start:

• The syslog-ng OSE application will connect to database automatically after starting regardless existing incoming messages.

Stop:

• The syslog-ng OSE application will close the connection to database before shutting down.

Possibility of losing logs:

• The syslog-ng OSE application cannot lose logs during shutting down if disk buffer was given and it is not full yet.

• The syslog-ng OSE application cannot lose logs during shutting down if disk buffer was not given.

Reload:

• The syslog-ng OSE application will close the connection to database if it received SIGHUP signal (reload).

• It will reconnect to the database when it tries to send a new message to this database again.

Macros:

The value of ${SEQNUM} macro will be overrided by sql driver regardless of local or relayed incoming message.

It will be grown continously.