EQ_DBSERVER=invent9k.external.hp.com:8102
This specifies that the specified server instance manages the database. The default is used unless you provide more specific information.
Database security
The database server maintains a list of users. Database access privileges are assigned to groups, which are similar to IMAGE user classes. Then a user is made a member of one or more groups.
For each database, groups define the access rights. This is the equivalent of the
TurboIMAGE user classes, which can be defined in the PASSWORDS section in the schema file. The schema processor creates two default groups "public" and "dba".
The group "dba” provides administrative access to the server and all databases, but does not allow read access to the data (it does have the right to erase a data set).
The group "public" public allows read/write access to the data, but is not authorized to perform administrative tasks (it has the access rights defined for user class 0).
Other groups are created and provide the access rights defined in the schema file. Users can be associated with up to eight groups and get the summary rights associated with the groups. Unless associated with a group, no access to the database is possible. By default, the schema processor associates the user "dba" with the group "dba" and the user "public" with the group "public" and all other groups defined in the schema file. This can be changed with the dbutil utility.
In order to connect to the Eloquence database server a user name and password is required. The new DBLOGON procedure may be used to specify user and password. A file can be specified as the user name or password. A default user is used if no specific user is specified.
The EQ_DBUSER and EQ_DBPASSWORD environment variables may be used to specify the default user or the password. For example:
EQ_DBUSER=file:/home/mike/dblogon
EQ_DBUSER=mike
EQ_DBPASSWORD=file:/home/mike/passwd
Database environment
A database environment consists of a configuration file, one or more data volumes, and a transaction log volume. Multiple database environments can coexist on the same machine, each managed by a separate server process.
Volume files
The Eloquence database does not reside in the file system but uses volume files, which reside in the file system as a container for the data and structural
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information. Volume files are a storage container managed by the database server.
All volumes combined define the disk space accessible to the database server. The maximum size of a single volume file is 128 GB. As of Eloquence B.07.00 a single volume file is limited to 2 GB on the HP-UX and Linux platform (we currently don't use 64 bit file operations on HP-UX and Linux to maintain compatibility with older operating system versions). On the Windows platform we support 64 bit file operations so the 2 GB limit for a single volume does not apply.
A maximum of 255 volume files is supported by a single server instance, which defines an upper limit of about 500 GB for the current version and up to 32 TB once the 2 GB limit has been removed.
Volume files are specific to the system architecture (byte order).
Server catalog
Eloquence does not use a ROOT file. Database structural information is maintained in the database environment, called the server catalog. The catalog is an internal database maintained by the server process. The server catalog is created and initialized with the dbvolcreate utility (which is used to create the primary data volume) and maintained with database utilities, such as the schema processor or the dbutil utility. The dbdumpcat utility allows reading the server catalog.
Database limits – the Eloquence B.07.00 Image limits:
• 2048 data items
• 500 data sets
• 64 / 16 paths
• Entry length 5120 bytes
The Eloquence B.07.00 database either matches or exceeds the TurboIMAGE schema limits. Most TurboIMAGE limits do not apply to Eloquence because the underlying architecture is different, and Eloquence allocates most resources dynamically.
Although the Eloquence database may exceed the TurboIMAGE limits in some cases, you should be careful before making use of that fact. Applications may need to be reviewed, if they support the increased limits. As the IMAGE intrinsics do not specify buffer sizes (this is especially important with DBINFO as it returns a variable sized result) this may result in application crashes due to a buffer overflow. With the
Eloquence TurboIMAGE compatibility API, DBINFO mode 406 returns information about database schema size.
Disk space within the volume files is allocated dynamically. A single data set can span multiple volumes and is therefore not limited to the size of a single volume file.
Transactions can grow dynamically and are only limited by available disk space in the log volume(s).
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