This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
– ISINSTANCE_MODIFIABLE (144 TRUE, 112 FALSE): for clustered databases such as RAC, this shows if the parameter can be modified on global (TRUE) or local (FALSE)
– DISPLAY_VALUE: displays data slightly better in some cases. For example, db_cache_size’s VALUE=25165824 and DISPLAY_VALUE=24M db_recovery_file_dest_size’s VALUE=2147483648 and DISPLAY_VALUE=2G
In 10g, the init parameters are broken into:– “BASIC”, with 29 parameters that should
be modified for tuning– “ADVANCED” for the fine-tuning of
databases and to keep us all employed. This is a nice reduction in the number of parameters. For example, shared server environments are handled by Oracle (SHARED_SERVERS init parameter, no longer the DISPATCHER init parameter)
Server Manageability• 10g provides for easier installation, configuration, management (and dropping!) of
databases.• Much improved Oracle Enterprise Manager• Automatically configure RAC clustered environments• Automatic Storage Management (this was part of Oracle 9i, but there are
additional improvements in 10g): new volume manager for Oracle-based files. Oracle attempts to optimally create and distribute datafiles, log files, and controlfiles. Mirroring and available disks are taken into consideration, and Oracle can redistribute the files for balancing if there are I/O bottlenecks.
• Transparent gateway: use SELECT to refer to remote functions in non-Oracle databases.
• 10g Initialization Parameters:
– instance_typeDescription from V$PARAMETER
type of instance to be executed
Default Value rdbms
Notes Two values: RDBMS for a database instance, ASM for an Automatic Storage instance
Server Manageability• 10g Initialization Parameters:
– asm_diskgroups
– asm_diskstring
Description from V$PARAMETER
disk groups to mount automatically
Default Value {null}
Notes List of disk groups for the ASM to mount at STARTUP or “ALTER_DISKGROUP ALL MOUNT”. Oracle dynamically modifies this parameter when disk groups are mounted/dismounted
Example Group1, Group2Description from V$PARAMETER
disk set locations for discovery
Default Value {null}
Notes Oracle uses this parameter to perform automatic discoveries for which disks are available. The instance needs read/write access to the directory to be considered.
Server Manageability• 10g Initialization Parameters:
– asm_power_limit
– fileio_network_adapters
Description from V$PARAMETER
number of processes for disk rebalancing
Default Value 1
Notes ASM power for automatic disk rebalancing. This is on a scale of 1 to 11. 1 takes longer but consumes fewer CPU and i/o resources. 11 is faster but consumes more CPU and i/o.
Example 5
Description from V$PARAMETER
Network Adapters for File I/O
Default Value {null}
Notes Lists the addresses of network adapters to access disks. Useful for NAS (network attached storage).
Database Self-Management• Automatic Workload Repository: a set of tables that is a
repository of workload statistics, enabling Oracle 10G to self-manage. Querying against this repository is a wealth of information, analogous to the BSTAT/ESTAT and tracing options for tuning in Oracle 9. Stored in a separate repository database with OEM.
• 10g Views: New columns:– V$AW_CALC (SESSION_ID, CURR_DML_COMMAND,
Database Self-Management• Automatic UNDO RETENTION tuning: Oracle 10G can
dynamically adjust the init parameter UNDO_RETENTION, which looks at the space in the UNDO tablespaces and automatically adjusts as new SQL queries are executed. This helps to avoid the “snapshot too old” errors.
• 10g Views:
– V$UNDOSTAT: new columns• MAXQUERYID• ACTIVEBLKS• UNEXPIREDBLKS• EXPIREDBLKS• TUNED_UNDORETENTION
Database Self-Management• Users can now have more than one TEMP tablespace defined with a “tablespace group”, so creating large objects such as
indexes or running large GROUP BY or DISTINCT queries can spill into additional TEMP tablespaces without failing as in Oracle 9 and earlier versions.
• SGA:• 10g Initialization Parameter:
– sga_target
• Cache:
• 10g View: V$DB_CACHE_ADVICE new columns:• ESTD_PHYSICAL_READ_TIME• ESTD_PCT_OF_DB_TIME_FOR_READS
Description from V$PARAMETER
Target size of SGA
Default Value 0
Notes Total size of DB_CACHE_SIZE, SHARED_POOL_SIZE, LARGE_POOL_SIZE, and JAVA_POOL_SIZE. Oracle’s ASM (Automatic Shared Memory) automatically and dynamically adjusts the SGA components during runtime. Additional pools are not affected: log buffer, KEEP/RECYCLE buffer cache, and Oracle Streams pool.
• Tablespace:• Rename Tablespace: before Oracle 10G, the DBA would need to create a
new tablespace, copy (or export/import data) into the new tablespace, and drop the original tablespace. Now you can simply RENAME the tablespace extremely quickly.
• 10g Views:– DBA_TABLESPACES: new columns:
• RETENTION• BIGFILE
– V$TABLESPACE: new columns:• BIGFILE• FLASHBACK_ON
Notes Tells Oracle if SQL queries automatically create outlines. TRUE creates outlines, FALSE disables the features, and setting to {category_name} stores the outlines linked to the specified category.
Example FALSE Description from V$PARAMETER
Disable NOWAIT DML lock acquisitions
Default Value FALSE
Notes TRUE – DDL statements wait to complete if there are blocking locks on the object. FALSE – DDL statements time-out if there are blocking locks
Notes Tells Oracle how PL/SQL is compiled within the database. Two values:INTERPRETED: compiles PL/SQL into bytecodeNATIVE: compiles PL/SQL into native (machine) code
Example NATIVE Description from V$PARAMETER
PL/SQL debug
Default Value FALSE
Notes Tells Oracle if PL/SQL can be compiled for debugging purposes. Two values:TRUE: PL/SQL will be compiled in debugging mode. Note that this overrides the plsql_code_type parameter to always be INTERPRETEDFALSE: PL/SQL is compiled without debugging
Notes PL/SQL optimization levels during compilation. This can result in improved compiled code. Three values:0: compile similar to Oracle9i’s compilation1: applies several optimization algorithms for PL/SQL compilation2: applies the most advanced optimization
Example 2 Description from V$PARAMETER
PL/SQL compiler warnings settings
Default Value DISABLE:ALL
Notes Tells Oracle how much detail, if any, to display with warning messages during PL/SQL compilation.Qualifier values:
Database Automatic Statistics• Automatic Optimizer Statistics Collection: collects statistics for objects that are either stale or don’t have them at all.• 10g Initialization Parameter:
– Statistics_level: default is TYPICAL, and the other option is BASIC. The SMON process wakes up every 2-3 hours, reviews the number of rows affected by INSERT / UPDATE / DELETE commands since the last statistics gathering. This process replaces the old DBMS_STATS built-in package.
• 10g Views:– *_TAB_MODIFICATIONS: determines which tables have stale statistics and which should be updated via the SMON
background process.
• Database Advisors: – Oracle tracks usage more than Tivo. The DBA can collect data on what Oracle functions are being used (Parallel Queries, IOTs,
etc) for information and tracking.– Segment Advisor: Stores data on object growth trends and helps make DBAs with capacity planning. The Segment Advisor
also looks within tables to see if any should be defragmented. This new online defragmentation includes reducing the highwater mark from empty blocks, or if data is out of whack with PCTUSED / PCTFREE, tables can be rebuilt online to compact data.
– Redo Log Sizing Advisor: self-explanatory– SQL Tuning Advisor, SQL Access Advisor: makes suggestions for improving the syntax of SQL statements, the way some
3rd-party vendors did prior to Oracle 10G. Also recommends adding indexes, materialized views, etc.– Transaction Rollback and Recovery Monitoring: predict how long a rollback will take, monitor long-running transactions
Object Management• Tablespaces: New SYSAUX tablespace is for system auxiliary objects. Now you do not need to put
everything into the SYSTEM tablespace.• Object Types:New “Sorted Hash Cluster” object type. Useful to retrieve data in the exact order it was
INSERTed• Tables:
– DBA_TABLES:• MAXTRANS deprecated.• New columns COMPRESSION (DISABLED, ENABLED, null) and DROPPED (YES, NO)
– DBA_TAB_COLS: new columns (HISTOGRAM, QUALIFIED_COL_NAME)– DBA_TAB_COLUMNS: new column (HISTOGRAM)– DBA_TAB_COL_STATISTICS: new column (HISTOGRAM)– DBA_TAB_MODIFICATIONS: new column (DROP_SEGMENTS)
• Indexes:– DBA_INDEXES new columns (IOT_REDUNDANT_PKEY_ELIM, DROPPED)
• 10g Initialization Parameter:
– skip_unusable_indexes
Description from V$PARAMETER
skip unusable indexes if set to TRUE
Default Value TRUE
Notes Two values:TRUE: skips error reporting on indexes and index partitions and allows for DML on base tables with UNUSABLE indexes.FALSE: tells Oracle to return an error when DML on base tables with UNUSABLE indexes occurs.
– DBA_LOG_GROUPS: new columns (TABLESPACE_NAME, FORMAT, PARTITIONED)
– V$TEMPORARY_LOBS: new column (ABSTRACT_LOBS)
• Log Groups:– DBA_LOG_GROUPS: new columns (LOG_GROUP_TYPE, GENERATED)
• Materialized Views:– DBA_MVIEWS: new columns (UNKNOWN_TRUSTED_FD, STALE_SINCE)
• Online Segment Shrink: This new online defragmentation includes reducing the highwater mark from empty blocks, or if data is out of whack with PCTUSED / PCTFREE, tables can be rebuilt online to compact data. This is possible with tables, indexes, and materialized views.
Backup and Recovery• 10g has new automated disk-based backup & recovery features.• New / improved commands:
– DROP DATABASE command: physically deletes all datafiles, spfiles, controlfiles, redo logs– ALTER DATABASE OPEN RESETLOGS: no longer need to backup the database instance following this
command– ALTER DATABASE BEGIN BACKUP: No longer need to cycle through each tablespace to put into hot backup
mode. Can now do the entire database– Automatic TSPITR (tablespace point-in-time recovery)
Backup and Recovery• 10g Initialization Parameters:
– db_flashback_retention_target
– db_recovery_file_dest
Description from V$PARAMETER
Maximum Flashback Database log retention time in minutes.
Default Value 1440
Notes The upper limit for time (in minutes) that the database should retain data for flashing back information.
Example 2000
Description from V$PARAMETER
default database recovery file location
Default Value /usr/db/flash_recovery_area
Notes This is the “flash recovery” directory or disk group. The “flash recovery” directory contains copies of controlfiles, redo logs, archived redo logs, flashback logs, and RMAN backup files.
Backup and Recovery• RMAN:• 10g can automatically create and recover datafiles that have never been backed up. Also when
RMAN detects a corrupt backup it can automatically go one backup into the past to recover.• The DURATION clause of the BACKUP command sets the seconds that a backup is allowed to
run, at which point RMAN can pause and/or resume.• Can alert the DBA when the backup is about to run out of space.• 10g Views:
– V$DATAFILE_COPY: new columns (IS_RECOVERY_DEST_FILE, RMAN_STATUS_RECID, RMAN_STATUS_STAMP)
– V$BACKUP_PIECE: new columns (BYTES, IS_RECOVERY_DEST_FILE, RMAN_STATUS_RECID, RMAN_STATUS_STAMP, COMPRESSED)
– V$BACKUP_SINC_ID: new columns (RMAN_STATUS_RECID, RMAN_STATUS_STAMP)– V$DATAFILE_COPY: new columns (IS_RECOVERY_DEST_FILE, RMAN_STATUS_RECID,
RMAN_STATUS_STAMP)– V$PROXY_ARCHIVELOG: new columns (TAG, RMAN_STATUS_RECID, RMAN_STATUS_STAMP)– V$PROXY_DATAFILE: new columns (RMAN_STATUS_RECID, RMAN_STATUS_STAMP)
Backup and Recovery• Flashback Query Improvements:• Can recover an entire database to an earlier point-in-time, reducing or removing the need to use the
traditional tape backup and recovery methods.
• FLASHBACK DATABASE: entire database restored to a point-in-time• FLASHBACK TABLE command: entire table restored to a point-in-time. Oracle now puts dropped tables
into the “recycle bin” for quick and easy recovery. In SQL*Plus you can type “SHOW RECYCLEBIN bin_name”
• Flashback drop: restore a table that was dropped entirely• Flashback version query: view data at the row-level and the history of changes• Flashback transaction query: view data and changes on a transaction-level for more finely-grained
High Availability• Data Guard: 10g Initialization Parameters:
– db_unique_name
– log_archive_config
Description from V$PARAMETER
Database Unique Name
Default Value {ORACLE_SID}
Notes Helpful for Data Guard, DB_UNIQUE_NAME is the global unique database name. This differentiates different databases with the same DB_NAME and the same DB_DOMAIN
Example ORAPROD Description from V$PARAMETER
log archive config parameter
Default Value ‘SEND, RECEIVE, NODG_CONFIG’
Notes Tells Oracle information on how to send redo logs to remote destinations in Data Guard environments.SEND/NOSEND (send the redo logs to remote destinations or not)RECEIVE/NORECEIVE (receive redo logs from remote destinations or not)DG-CONFIG/NODG_CONFIG (list of unique database names in the Data Guard configuration. 0-9 unique names are allowed)
Notes For Data Guard configurations:TRUE: uses the ARC background processes to send redo logs to remote destinations once an online log is archived. Good for slow WAN networks.FALSE: uses the ARC background processes to send logs to remote destinations simultaneously to the local archive copying. Good for fast LAN environments.
High Availability• RAC (Real Application Clusters):• As part of the new Enterprise Manager, Oracle now provides clusterware management
software similar to the 3rd-party software available prior to Oracle 10G. It provides a nice dashboard of overall node statuses with drilldown capabilities.
• Automatic Workload Management: DBAs create workloads and then manage CPU resources for each process.
• Zero Downtime Patching: by using RAC, you can apply patches (database or server) to one node at a time to avoid downtime.
• Upgrade Oracle versions “online” with the Rolling Upgrade. Uses logical standby databases and SQL apply technology
• New RAC 10g Views:– DB_UNIQUE_NAME: can dynamically add a standby database without shutting down the primary
• EUS: Enterprise User Security. Single sign-on capabilities. A central OID/LDAP repository. Can manage Oracle Label Security policies and user label authorities.
• 10g Views: New columns in:– DBA_POLICIES: (IDX, POLICY_TYPE, LONG_PREDICATE)
– ldap_directory_access Description from V$PARAMETER
RDBMS's LDAP access option
Default Value NONE
Notes Three values that determines if / how Oracle authenticates to the Internet Directory: This is for enterprise security.NONE: Oracle doesn’t authenticate at allPASSWORD: connect with the password stored in the database “wallet”SSL: connect with SSL
WHERE issys_modifiable IN (’DEFERRED’,‘IMMEDIATE); NAME VALUE ISSAYS MODTimed_statistics False IMMEDIATELog_checkpoint_interval 5000000 IMMEDIATELog_checkpoint_timeout 21600 IMMEDIATEObject_cache_optimal_size 102400 DEFERREDBackground_dump_dest /u02/oracle/PHIS/bdump IMMEDIATESort_area_size 5096000 DEFERRED