Andreas_Sprosec_7439

What is Lobsegment, Lobindex (Oracle)?

Discussion created by Andreas_Sprosec_7439 on Jul 24, 2017

You Asked


I query table 'user_segments': 

select segment_name, segment_type, tablespace_name, bytes, max_extents

 from user_segments

where segment_type NOT IN ('TABLE','LOBSEGMENT'); 

result is 

SEGMENT_NAME SEGMENT_TYPE TABLESPACE_NAME

SYS_IL0000018977C00010$$       LOBINDEX           UC4_DATA         65536    2147483645

SYS_IL0000018977C00011$$       LOBINDEX           UC4_DATA    65536         2147483645 


What is Lobsegment, Lobindex and why need it? 


And we said … 


A LOB is simply a pointer. It points to an index. The index points to the chunks that make up the LOB. 

Hence when you create a LOB, you will always get a lob index created (to find the chunks for the lob fast) and a segment that holds the lob data (chunks).

 

 

You can only "delete" it by dropping the table or column that contains the LOB.

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