Oracle Essentials Oracle Database 11g by Rick Greenwald

including:
    • The name of the database
    • When the database was created
    • Names and locations of datafiles and redo log files
    • Tablespace information
    • Datafile offline ranges
    • The log history and current log sequence information
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    • Archived log information
    • Backup set, pieces, datafile, and redo log information
    • Datafile copy information
    • Checkpoint information
    In addition to providing fundamental information at startup, control files are also useful when removing a database. Since Oracle Database 10 g , the DROP DATABASE command can be used to delete the database files listed in the database control file as well as the control file itself.
    Database Initialization
    At Oracle database instance startup, initialization parameters are read to determine how the database will leverage physical infrastructure and for other key instance configuration information. Initialization parameters are stored in an instance initialization parameter file, often refered to as INIT.ORA , or, since Oracle9 i , in a repository called the server parameter file (or SPFILE ). The number of initialization parameters that must be specified has been greatly reduced with each Oracle database release. Oracle provides a sample initialization file that can be used at database startup, and the Database Configuraton Assistant (DCA) prompts you for values that must be provided on a custom basis (such as database name).
    The set of initialization parameters that must be specified in Oracle Database 11 g include:
    CONTROL_FILES
    The control file locations
    DB_NAME
    The local database name
    DB_DOMAIN
    The database domain name (such as us.companyname.com)
    LOG_ARCHIVE_DEST
    The log archive destination
    LOG_ARCHIVE_DEST_STATE
    The parameter that enables log archiving
    DB_RECOVERY_FILE_DEST
    The location of the database flash recovery area (directory, filesystem, or ASM
    disk group)
    DB_RECOVERY_FILE_DEST_SIZE
    The database flash recovery area maximum size in total bytes DB_BLOCK_SIZE
    The database block size in bytes (e.g., 4 KB = 4,096)
    Databases and Instances
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    PROCESSES
    The maximum number of concurrent database operating system processes SESSIONS
    The maximum number of database sessions
    OPEN_CURSORS
    The maximum number of database open cursors
    SHARED_SERVERS
    The minimum number of database shared servers
    REMOTE_LISTENER
    The remote listener name
    COMPATIBLE
    The database version youwant for compatibility where features affect file format (e.g., 11.1.0, 10.0.0)
    MEMORY_TARGET
    The target memory size that is automatically allocated to SGA and instance PGA components
    DDL_LOCK_TIMEOUT
    For data definition language (DDL) statements, the time a DDL statement waits for an exclusive lock (in seconds) before failing
    NLS_LANGUAGE
    The National Language Support (NLS) language specified for the database NLS_TERRITORY
    The National Language Support territory specified for the database As an example in the shift toward automation, in Oracle Database 11 g , the UNDO_
    MANAGEMENT parameter default is now set to automatic undo management.
    Undo is used in the rollback of transactions, and for database recovery, read consistency, and flashback features. (Redo records, though, reside in the physical redo logs; they store changes to data segments and undo segment data blocks, and they hold a transaction table of the undo segments.) The undo retention period is now self-tuned by Oracle based on how the undo tablespace is configured.
    For your database release, check the documentation regarding optional initialization parameters as these change from release to release. Some of them are described in the following sections.
    Deploying Physical Components
    This section is not a substitute for Oracle’s installation procedures, but it should provide you with some practical guidance as you plan deployment of an Oracle database.
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    Control Files
    A database should