Latest Answer : these r the extents which indicates data was not stored in the segment. ...
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
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
Each block contains entries as followsFixed block headerVariable block headerRow Header,row date (multiple rows may exists)PCTEREE (% of free space for row updation in future)
Latest Answer : A block is divided into1. Header2.free space3.data spaceThe free space is in the middle shrinks as header and data space grow.Space usage in the data space :The data space is managed with 2 parametersa.pctused b.pctfreesuppose pctused=40 ...
To manage the database level transactions such as modifications of the data dictionary table that record information about the free space usage.
Latest Answer : 1.System tablespace is required in all databases.2.It is created with the database.3.Contains the data dictionary and stored program units.4.Contains SYSTEM undo segment. ...
It will try to fit the transaction in a cyclic fashion to all existing extents. Once it found an extent is in use then it forced to acquire a new extent (No. of
Rollback segment dynamically extent to handle larger transactions entry loads. A single transaction may wipeout all available free space in the Rollback Segment
List the sequence of events when a large transaction that exceeds beyond its optimal value when an entry wraps and causes the rollback segment to expand into another extend. Transaction Begins. An entry is made in the RES header for new transactions entry Transaction acquires blocks in an extent of RBS The entry attempts to wrap into second extent. None is available, so that the RBS must extent. The
Limit the number of extents in the tableSeparate Table from its indexes.Allocate Sufficient temporary storage.
