ER Diagram

The utility uses a set of tables to store the messages and the configuration. This is the entity/relation diagram of the database.

First line: Table's name
# Primary key (mandatory.)
* Mandatory field.
o Optional field.

      ++==============================---------------+
      ||                                             '
      ||                                             A
+------------+             +-------------+  +-----------------------+
| LEVEL      |             | CONF_LOGGER |  | CONF_LOGGER_EFFECTIVE |
| # LEVEL_ID |======- - - <| # LOGGER_ID |  | # LOGGER_ID           |
| * NAME     |             | * NAME      |  | * LEVEL_ID            |
+------------+        + - <| o PARENT_ID |  | * HIERARCHY           |
     ||               '    | o LEVEL_ID  |  +-----------------------+ 
     ||               '    +-------------+              -'-
     ||               '     ||    ||  ||                 '
     ||               '     ||    ||  ||                 '
     ||               +=====++    '   ++======-----------+
     ||                           '
     ||                          -A-
     '                     +-------------------+
     '                     | REFERENCE         |
     '                     | # LOGGER_ID       |
     '                     | # APPENDER_REF_ID |
     '                     +-------------------+
     '                              -V-
     '                               '
     +-----------------------+       '
                             '       ||
                             A       ||
                          +-----------------+
+---------------+         | CONF_APPENDER   |
| APPENDER      |         | # REF_ID        |
| # APPENDER_ID |====- - <| * NAME          |
| * NAME        |         | * APPENDER_ID   |
*---------------+         | o CONFIGURATION |
                          | * PATTERN       |
                          +-----------------+

+---------------+
| CONFIGURATION |
| # KEY         |
| o VALUE       |
+---------------+

+-------------+
| LOG         |
| * DATE      |
| o LEVEL_ID  |
| o LOGGER_ID |
| * MESSAGE   |
+-------------+

+----------------------+ +------------------+ +-------------+
| CONF_APPENDER_HIST   | | CONF_LOGGER_HIST | | LOG_HIST    |
| # REF_ID             | | # LOGGER_ID      | | * DATE      |
| * NAME               | | * NAME           | | o LEVEL_ID  |
| * APPENDER_ID        | | o PARENT_ID      | | o LOGGER_ID |
| o CONFIGURATION      | | o LEVEL_ID       | | * MESSAGE   |
| * PATTERN            | | * BUS_START      | | * SYS_START |
| * BUS_START          | | * BUS_END        | | * SYS_END   |
| * BUS_END            | | * SYS_START      | +-------------+
| * SYS_START          | | * END_START      |
| * END_START          | | * TS_ID          |
| * TS_ID              | +------------------+
+----------------------+

Remember that the real names of the tables are in plural, but in an E/R diagram are in singular.

All these tables except LOGS are in the LOGGER_SPACE tablespace. LOGS is in the LOG_DATA_SPACE tablespace that has different characteristics to improve the performance while writing. The tablespace with 8 KB page size was selected because it could contain minimum 29 rows (when the message uses the full capacity), and a maximum of 255 when the messages are very short (Without compression, in row-store, in regular tablespace-not large).

The LOG_HIST table is created like LOG, but at that time, two more columns are added in order to enable the temporal capabilities.

In a similar way, CONF_LOGGER_HIST and CONF_APPENDER_HIST are created like CONF_LOGGERS, but the extra columns are added when the temporal capabilities are enabled.