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Hi guys,
What is the diff. between NUM_ROWS in DBA_INDEXES and DBA_TABLES.
Also, does any one have sizing formula for B*tree indexes?
Thanks in Adv.
Sam
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To handle yourself, use your head. To handle others, use your heart
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dba_tables tells you number of rows you have in the table
dba_indexes tells you how many rows is stored in index
because index do not store nulls you see different results
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Originally posted by samdba
What is the diff. between NUM_ROWS in DBA_INDEXES and DBA_TABLES.
NUM_ROWS in DBA_TABLES shows the count of all rows in the table. The same column in DBA_INDEXES on the other hand shows the number or rows in the table that have an entry in that index. As you know, B*Tree index does not store index entries for rows taht have NULLs in all columns that comprise the index, so the number in DBA_INDEXES could be smaller than the one in DBA_TABLES if indexed collumns contain NULLs.
Jurij Modic
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
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DBA_INDEXES:
NUM_ROWS NUMBER Number of rows in the index
DBA_TABLES:
NUM_ROWS NUMBER Number of rows in the table
The concepts guide talks about how the B*tree indexes are
stored and under what conditions key compression can
be used to reduce storage requirements.
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Paul
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Thanks to all of you,
Does any one have sizing formula for B*tree indexes?
Thanks.
Sam
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To handle yourself, use your head. To handle others, use your heart
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I dont because I dont size segments anymore with LMT....
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Should someone mention that in both cases NUM_ROWS is only as accurate as you last analyze?
MH
I remember when this place was cool.
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