storagestructures1

storagestructures1 - Segment- space occupying object in the...

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Segment- space occupying object in the database and is made up of one or more extents. types of segments= table, cluster, LOB segment, index, rollback segment Factors that influence storage allocation: Changes to storage parameters affect only extents allocated subsequently Some parameters can be spefcified at the segment level only Minimum extent size specified for tablespace applies to all the extents allocated for segments in the tablespace DBA_FREE_SPACE_COALESCED- view to determine whether you need to coalesce free extents within a tablespace ALTER TABLESPACE tablespace COALESCE' ALTER TABLESPACE data COALESCE Data BLock contains- Block header, free space, data space Value of the PCTFREE parameter is specified as 30- drops SELECT tablespace_name, COUNT(*), SUM(blocks) from dba_free_space GROUP BY tablespace_name
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A database that has multiple tablespaces requires at least one non-SYSTEM rollback segment. Process used to ensure read consistency
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storagestructures1 - Segment- space occupying object in the...

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