Answered by: Lachi on 2005-06-08 07:28:04For perticular transaction Alter system set rollback segment 'name'; For database, we can set in pfile. Rollback_segment='name'

Lakshminarayan.

• Jun 13th, 2005

In above answer one correction is there,  For perticular transaction we can use fallowing syntax.  >set transaction use rollback segment 'name'

Lachi

• Jun 8th, 2005

For perticular transaction Alter system set rollback segment 'name'; For database, we can set in pfile. Rollback_segment='name'

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Ravi Prakash Pichika

• Jun 11th, 2005

The Control File is a small binary file necessary for the database to start and operate successfully. Each Control file is associated with only one Oracle database. Before a database is opened, the co...

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Ravi Prakash Pichika

• Jun 6th, 2005

PGA - Program Global Area  or the Process Global Area is a memory region that contains data and control information for a single server process or a single background process.   Th...

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 The  System   Global  Area  in  a  Oracle database is the area in memory to facilitates  the  transfer  of information between users. It holds the most recently requested structural information between users. It holds the most recently requested structural information about the database. The structure is Database buffers, Dictionary cache,...

 The data dictionary cache is stored in an area in SGA called the Shared SQL Pool.  This will allow sharing of parsed SQL statements among concurrent users.

 It is area in memory that is used by a Single Oracle User Process.

 Data segment are the physical areas within a database block in which the data associated with tables and clusters are stored.

 Due to insufficient Shared SQL pool size. Monitor   the ratio of the reloads takes place while executing SQL statements.   If   the   ratio   is   greater than 1 then increase the SHARED_POOL_SIZE. LOGICAL & PHYSICAL ARCHITECTURE OF DATABASE.

 Database buffers are cache in the SGA used to hold the data blocks that are read  from  the  data  segments in the database such as tables, indexes and clusters DB_BLOCK_BUFFERS parameter in INIT.ORA decides the size.

 Dictionary  cache is information about the databse objects stored in a data dictionary table.

 Number  of  times processes repeatedly query the dictionary table is called recursive  hints.  It  is due to the data dictionary cache is too small. By increasing the SHARED_POOL_SIZE parameter we can optimize the size of Data Dictionary Cache.

 Changes made to entries are written to the on-line redo log files. So that they can be used in roll forward operations during database recoveries. Before  writing  them  into  the redo log files, they will first brought to redo  log  buffers  in  SGA  and  LGWR  will  write  into files frequently.LOG_BUFFER parameter will decide...

 SYSTEM - Data dictionary tables.DATA  - Standard operational tables.DATA2- Static tables used for standard operationsINDEXES - Indexes for Standard operational tables.INDEXES1 - Indexes of static tables used for standard operations.TOOLS - Tools table.TOOLS1 - Indexes for tools table.RBS - Standard Operations Rollback Segments,RBS1,RBS2 - Additional/Special Rollback segments.TEMP - Temporary...

 A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents are reallocated and are marked as free.

 Free extents cannot be merged together in Ver 6.0.Free extents are periodically coalesces with the neighboring free extent inVer 7.0

 PCTFREE parameter Row size also reduces no of rows per block.

 We  can  plan  the  storage  for  a  table  as how much initial extents are required,  how  much can be extended next, how much % should leave free for managing row updations etc.,

 This is used to reserve certain amount of space in a block for expansion of rows.